microwave food experiment

The Science Oven

How a microwave cooks your food, claire maldarelli • july 10, 2014.

Warm Nutella mug cake, fresh out of the…microwave [Image credit: Flickr user Suanie]

Video: traveling faster than the speed of light, kathryn free • february 3, 2014, an idea for ideas, hannah newman • february 12, 2014, the little engine that could, elizabeth newbern • march 17, 2014, thinking machines, sarah lewin • june 13, 2014.

For five months straight, I lived in a hotel without a kitchen. Everything I ate was cooked in a microwave. At first, I craved the meals that required a convection oven. But by the end, I found I could make almost anything in a microwave.  My favorite concoction was Nutella mug cake — a sinful, gooey, moist chocolate cake cooked in my favorite coffee mug in just under two minutes.

But how does a microwave actually work? And what makes it so different from a convection oven? The microwave was invented, accidentally , by American engineer Dr. Percy LeBaron Spencer. When testing a magnetron, a vacuum tube that generates microwaves, he realized the candy bar in his pocket had melted. After seeing what happens when other foods (popcorn and eggs) were placed in front of the magnetron, he quickly realized that microwaves could cook foods rapidly.

A microwave oven has three main parts: a magnetron (located on the side of the microwave) that makes microwaves, a waveguide (located within the wall of the microwave) that directs the microwaves from the magnetron to the food, and a compartment (where you place your food or beverage) to enclose both the food and the microwave radiation. Microwaves — just like radio waves, X-rays and visible light waves — are a kind of electromagnetic wave. But they have a unique property that makes them particularly useful for cooking food.

All electromagnetic waves operate at different wavelengths. Microwaves are wedged right in between radio waves and infrared light. At this frequency, something interesting happens. Water molecules, which are made up of one oxygen atom and two hydrogen atoms, are, by nature, polar — the oxygen atom steals more of the negative electrons than the hydrogen atoms do, making the oxygen slightly more negative and the two hydrogen atoms slightly more positive. Food is full of these slightly polar water molecules. When left alone, they stay still.

As a microwave travels, its electrical and magnetic fields change rapidly. When the wave travels near a water molecule, the molecule will try to align with the electrical field. Since the field is constantly changing, the water molecule rocks back and forth, generating energy in the form of heat. When the waveguide directs the microwaves, generated from the magnetron, into the compartment, all the water molecules are excited at once. This produces a lot of heat and cooks the food.

Frequency is the key to this effect. If you pass radio waves or infrared light through food, the water molecules will remain still as if nothing happened. But microwaves are at just the right frequency to excite the water molecules and generate heat — something other forms of electromagnetic waves can’t do.

In a traditional oven or stove, heat moves slowly from the outside in. But because microwaves travel straight through the food, exciting all the water molecules at once, a microwave oven cooks food evenly throughout. When heating food in a plastic or glass container, the microwaves pass straight through those containers with no interaction, making them microwave safe. But when heating food in a metal container, the metal will reflect the microwaves, causing sparks and sometimes a fire. So, experiment with your microwave. Go crazy. Make Nutella mug cake or your own version. But listen to Irving in American Hustle and never put metal in your science oven.

About the Author

Claire Maldarelli

Claire received her B.S. in neurobiology, physiology, and behavior from the University of California, Davis. Originally an animal science major with ambitions of becoming a veterinarian, she quickly learned she and large animals would never be friends. Instead, she spent her time in college studying science, writing for her school newspaper, The California Aggie, and working with military children in Japan, Germany, and Hawaii for Camp Adventure Youth Services.

Don’t microwaves irradiate your food? Making microwaved food unhealthty?

Not all plastics are safe in the microwave !!!

Metal is unsafe in microwave not because it reflects microwaves. Microwaves induce an electric current in metals, and if the metal object has sharp corner, as in a fork or crumpled foil, the current can jump through air, causing sparks. Smooth metal does not cause problems in a microwave, but it’s better to be safe and not experiment.

And to answer commenter Tracy, yes strictly speaking, microwaves irradiate your food, but only in the sense that all electromagnetic waves (including visible light) irradiate something. Microwaves are non-ionizing, that is they can’t break chemical bonds the way x-rays and gamma rays can. All they do is jiggle the molecules, heating them up, as described in the article.

SuzanneLexington, KentuckyMy daughter just moved into a new aemntaprt and I wanted to get her a housewarming gift. The one thing she kept really hinting for was a microwave. So I found this GE Spacemaker and thought it would be just right for her aemntaprt kitchen. You know how aemntaprts are on space and this wouldn’t take up a lot of room at all. She was pretty excited when I presented it to her and tried it out immediately while I was still there.It works great for reheating things as well as cooking entire meals, as I found out when she made dinner for her father and me the other night. The food cooks completely and quickly. It allows her to do preparations on other things while one dish cooks so it’s also a real timesaver. Some of her friends have already asked her where she got her microwave so they can get one, too. I guess that’s a pretty good testimony as to what a good microwave this is.

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Microwave’s Hidden Impact: The Surprising Truth About How It Changes Food’s Molecular Structure

What To Know

• For decades, microwaves have been a staple in kitchens worldwide, offering a quick and convenient way to heat food.
• The notion that microwaves can alter the molecular structure of food is often attributed to the perception that microwaved food sometimes tastes or appears different compared to conventionally heated food.
• Prolonged exposure to high temperatures, regardless of the heating method, can lead to the degradation of heat-sensitive nutrients, such as vitamin C and some B vitamins.

Does Microwave Change Molecular Structure of Food?

Understanding microwaves: a brief overview, impact of microwaves on molecular structure: separating fact from fiction, nutritional value and microwaving: a delicate balance, addressing common misconceptions about microwaving food.

For decades, microwaves have been a staple in kitchens worldwide, offering a quick and convenient way to heat food . However, concerns have been raised regarding the potential impact of microwaves on the molecular structure of food. In this comprehensive exploration, we delve into the science behind microwaves, examining whether they indeed alter the molecular makeup of food and addressing common misconceptions surrounding this topic.

Microwaves are a form of electromagnetic radiation, occupying a frequency range between radio waves and infrared radiation . They work by exciting water molecules within food, causing them to vibrate rapidly, generating heat. This process, known as dielectric heating, allows for rapid and uniform heating of food.

The notion that microwaves can alter the molecular structure of food is often attributed to the perception that microwaved food sometimes tastes or appears different compared to conventionally heated food. However, scientific evidence suggests otherwise.

Microwaves, operating at a frequency of approximately 2.45 gigahertz, lack the energy required to break or rearrange chemical bonds within food molecules . Therefore, microwaves do not induce any significant changes to the molecular structure of food.

While microwaves do not alter the molecular structure of food, they can potentially affect its nutritional content. Prolonged exposure to high temperatures, regardless of the heating method, can lead to the degradation of heat-sensitive nutrients, such as vitamin C and some B vitamins. However, proper cooking practices, including appropriate power levels and cooking times, can minimize nutrient loss.

1. Myth: Microwaves Create Harmful Radiation in Food

Fact: Microwaves are a form of non-ionizing radiation, meaning they do not possess enough energy to damage DNA or cause cancer. The radiation emitted by microwaves is similar to that of radio waves and is considered safe for human consumption.

2. Myth: Microwaving Food Destroys Nutrients

Fact: As mentioned earlier, microwaving can potentially affect certain heat-sensitive nutrients. However, this is not unique to microwaves; all cooking methods can cause nutrient loss to varying degrees. With proper cooking techniques, microwaving can preserve nutrients just as effectively as other cooking methods.

3. Myth: Microwaving Food Alters the Chemical Composition of Food

Fact: Microwaves do not possess the energy required to break or rearrange chemical bonds within food molecules . Therefore, they do not induce any significant changes to the chemical composition of food.

Safe Microwaving Practices: Ensuring Optimal Results

To ensure safe and effective use of microwaves, follow these guidelines:

• Use microwave-safe containers and utensils.
• Avoid cooking food for extended periods at high power levels.
• Stir or rotate food during cooking to promote even heating.
• Allow food to rest for a few minutes after microwaving to ensure uniform heat distribution.

Wrap-Up: Embracing Microwaves as a Safe and Convenient Cooking Tool

In essence, microwaves do not alter the molecular structure of food. They are a safe and convenient way to heat food, provided proper cooking practices are followed. By dispelling common misconceptions and understanding the science behind microwaves, we can embrace this technology as a valuable tool in our culinary repertoire.

1. Can microwaving food cause cancer?

Answer: No, microwaving food does not cause cancer. Microwaves are a form of non- ionizing radiation and do not possess enough energy to damage DNA or cause cancer.

2. Does microwaving food destroy nutrients?

Answer: Microwaving can potentially affect certain heat-sensitive nutrients, but this is not unique to microwaves. All cooking methods can cause nutrient loss to varying degrees . With proper cooking techniques, microwaving can preserve nutrients just as effectively as other cooking methods.

3. Can microwaving food create harmful chemicals?

Answer: No, microwaving food does not create harmful chemicals. Microwaves do not possess the energy required to break or rearrange chemical bonds within food molecules . Therefore, they do not induce any significant changes to the chemical composition of food.

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Heat Things Up with these Microwave Experiments for Kids

Microwaves are not just for heating up leftovers! With a few simple materials and a bit of creativity, you can do some exciting and educational experiments in the microwave. From watching plasma sparks to blowing up marshmallows, these activities can help children learn about a variety of scientific principles while having fun.

Jump to your favorite activity:

Microwave Marshmallow Expanding Soap Plasma Grapes Dancing Raisins DIY Popcorn Lava Lamp Melting Chocolate

Microwave Marshmallow

In this experiment, kids will learn about the science of heat and how it affects marshmallows. They’ll be amazed as they watch the marshmallows expand before their eyes in the microwave.

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As the molecules inside the marshmallow vibrate faster, this movement creates heat, and the water inside the marshmallow turns into steam.

Related Post:  Find out how water changes states of matter and do some more fun experiments!

Expanding Soap

Microwaves are a type of electromagnetic radiation, which is a form of energy. When the microwaves from the oven hit the soap, they are absorbed by the water molecules and fatty acids inside the soap. This causes the soap to heat up and melt slightly.

It’s important to note that not all bar soap will expand when cooked in the microwave – it has to be Ivory brand soap specifically. This is because Ivory soap is made with a special whipped texture that incorporates lots of air bubbles. When heated in the microwave, these air bubbles cause the soap to expand dramatically.  Bars of soap from other brands won’t react the same way.

Plasma Grapes

Grapes are not a food we’d usually heat up to enjoy, but they make a cool simple science experiment with a great visual. While this experiment can be dangerous if not done properly, it’s a fascinating example of the science behind microwave radiation and plasma. Here’s how you can try it for yourself (with adult supervision, of course).

After a few seconds, you should see a small spark of plasma form where the two halves of the grape meet. If the grape doesn’t spark after 10 seconds, stop the microwave and check to make sure the grape is still intact. If it is, try again with a few more seconds of microwaving.

When you put a grape in the microwave, you’re witnessing a phenomenon known as plasma . The microwave radiation interacts with the grape’s skin, causing a small electrical current to be generated. This current flows through the grape’s flesh, creating a tiny spark of plasma at the point where the two halves of the grape meet.

Dancing Raisins

In this experiment, kids will learn about the science of carbon dioxide bubbles and how they can cause objects to move. They’ll have fun watching the raisins dance up and down in a glass of clear soda.

Materials needed:

Making Raisins Dance in the Microwave

Now we’ll bring the heat!  When you put raisins in the soda and then heat it in the microwave, the carbon dioxide bubbles become more active due to the increased heat energy. As the carbon dioxide bubbles rise to the surface of the liquid, they attach themselves to the rough surface of the raisins. When the bubbles reach the surface, they pop, causing the raisins to sink back down to the bottom of the glass.

This creates a cycle of rising and sinking that makes the raisins “dance” in the liquid. The effect is similar to the way bubbles in a boiling pot of water make pasta or vegetables move up and down.

It’s worth noting that the raisins won’t dance forever – eventually, the carbon dioxide bubbles will become less active as they dissipate into the air. And you’ll have some warm, flat soda.  But for a short time, it’s a fun and visually interesting experiment that demonstrates the principles of carbonation and gas behavior.  Our raisins slowed down after about 3 minutes after removing them from the microwave and had pretty much settled down after 4 or 5 minutes.

DIY Popcorn

By covering the popcorn kernels with a microwave-safe lid or plate, you create a sealed environment that allows the pressure to build up even more, resulting in more kernels popping at once. The steam that escapes from the popcorn kernels during popping not only adds pressure, but carries with it the delicious aroma that makes popcorn smell so good.

Once the popcorn is finished popping, you can season it with butter, salt, cheese, or other toppings to create a tasty snack. It’s important to note that not all types of popcorn are suitable for microwaving – If you’re using left over kernels from a bag of microwave-safe popcorn you shouldn’t have any issues..

When you add oil to water, it forms a separate layer on top because oil is less dense than water. In other words, a given volume of oil weighs less than an equal volume of water. When you heat up the mixture in the microwave, the water molecules start to move more quickly and spread out, making the water less dense. Meanwhile, the oil molecules stay the same size and shape, so the oil becomes more dense relative to the water.

The blobs of food coloring move up and down in the cup in a way that is reminiscent of a lava lamp, creating a fun and visually interesting display. The effect is due to the interaction between the different densities of the oil, water, and food coloring and the way that heat affects the density of substances.

Melting Chocolate

Though it’s best to heat the chocolate chips in short intervals, we used a medium heat setting and let it run uninterrupted for the sake of the video.

When the melted chocolate cools down, it solidifies again due to the re-solidification of the cocoa butter. This process is called crystallization. The chocolate will have a different texture and consistency than it did before it was melted, which can make it ideal for dipping or molding into different shapes.

Wrap Up – Microwave Experiments for Kids

This collection of microwave experiments for kids is a great way to get them interested in science and have fun in the kitchen. Not only do microwaves provide an easy way to heat food up quickly, but they can also be used to conduct exciting and educational experiments! So get out those ingredients and get ready for some hands-on learning with your little ones.

Howie Miller is as dedicated to fatherhood as he is to life long learning. Musician, Photographer, Educator, Consultant, Entrepreneur, Blogger, and founder of STEMtropolis, where you can share his adventures in STEM and STEAM with his family.

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Edible science experiments are a sweet blend of learning and indulgence, perfect for curious young minds with a hearty appetite for knowledge. Science is all about exploring, questioning, and...

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10 Food Science Experiments for Kids

Unlock the mysteries lurking in your pantry with science! Make a gummy bear double in size, toast marshmallows using solar power, use microwaves to make a chocolate cake in under a minute! This list of wacky ffood science experiments will reveal the hidden world of weird physics and strange chemical reactions involved in everything we eat. Next time you're at the grocery store, tell you're mom to get the giant bag of skittles. After all, it's for science!

(Ages 5-16 )

You may remember hearing about curds and whey from the old nursery rhyme about Little Miss Muffet. Well, this kitchen science experiment will teach you what curds and whey are, and you’ll even make some yourself! Curds and whey are a product of cheesemaking! Milk is made up of proteins, sugars, fat, minerals, vitamins, and enzymes. When you add an acid like lemon juice to warm milk, it causes molecules of one of the proteins in milk to bond to one another. That forms a solid lump of protein which is also known as a cheese curd (the leftover liquid is called whey.) You can eat cheese curds on their own (they taste like ricotta cheese) or top with honey or fruit for an awesome treat.

Want to explore more kitchen science experiments? Explore the tastier side of learning with Science of Cooking: Ice Cream from the KiwiCo Store !

Normally, a cake would take an hour or more to make in an oven, but with a microwave oven, you can make one in minutes! Microwave ovens use waves of energy called – you guessed it – microwaves to cook food quickly. The microwaves go into the food and make water molecules inside move around really fast. The movement creates heat which cooks the food. But the microwave is just one part of this scientific process. First, you need to mix up ingredients. Two of the ingredients are key to making a tasty mug cake! Baking powder will make your cake spongy because it produces gas bubbles that get trapped in the batter as it cooks. The egg will help your cake rise because it has proteins that create a strong structure. Without these ingredients, your cake will look like soup! Experiment with the other ingredients to customize your mug cake. What will you add to give it a whole new flavor?!

Want to explore more kitchen science experiments? Explore the tastier side of learning with Science of Cooking: Bread & Butter from the KiwiCo Store !

(Ages 3-8 )

If you have more candy than you know what to do with, try this experiment with your little ones. Sometimes playing with food is inevitable, but with sweet science comes knowledge!

Want to learn more about chemistry without the hassle of gathering materials? Explore 11 fun chemistry experiments with a Chemistry Play Lab from the KiwiCo Store !

Has your child ever wondered how plants get water from their roots all the way to their leaves? This simple celery experiment shows how colored water travels up a celery stalk!

Looking for more kitchen learning projects to do with your young scientist? Roll and stamp your way to early math exploration with a Fun Dough Pasta Maker from the KiwiCo Store !

(Ages 5-11 )

It is time for these little bears to grow up...and out with this gummy bear science project! Watch as gummy bears grow and shrink in different liquids in this kid-friendly experiment. This project is open for exploration and discovery, so kick things off by asking your child what they will happen to a gummy bear in water. Will it dissolve? Will it shrink or grow? Will it fall apart? How long will it take? Don’t forget to grab a notebook to write down their ideas so you can compare what they predicted with what actually happens! You’ll start to see results in just a few hours, and you’ll definitely see big changes in size in just a day.

(Ages 5-8 )

Pull a couple of cereal boxes from the shelf and test their iron content with this simple experiment. It's fun to see your breakfast whiz across the surface of milk using a magnet!

(Ages 3-11 )

See how a drop of soap can create an explosion of color with this easy experiment!

Have you ever tried to harness the power of the sun to create some s'mores? Camping is the perfect time to do it. During the day, I set up my DIY solar oven and stacked up my ingredients inside. Then, I just let it sit while I went for a quick hike around the campsite. When I returned, I had a delicious, melted snack that was ready to eat thanks to my solar oven!

Can you make an egg bounce? Try this simple chemistry experiment and see the shell of an egg dissolve! You'll be left with a surprise and a fun, bouncy egg. 

Discover everything that eggs have to offer with Eggsperiments from the KiwiCo Store ! Use the scientific method with a series of egg-based experiments that explore chemistry, physics, and biology.

Fall is coming, which means apple season is right around the corner. We love eating apple slices as a healthy snack. Try out this apple experiment with some basic kitchen goods to see how you can keep your slices from browning!

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Microwave Technology – Demystifying that Magical Box, Beloved by all Hungry College Students

BY: PRAVEENA THIRUNATHAN

How many of us have woken up in the middle of the night, hungry for something substantial, yet quick and easy to make? Anything using the oven or stove is out, as is cutting up and assembling a vast variety of delicious ingredients that most of us wouldn’t buy on our student budget. You stumble around in the dark, half awake but acutely aware of the grumbling within your tummy.

Then the wisps of a barely coherent thought gather in your head. You reach for the freezer, opening it to reveal Tupperware of food your roommates have brought from home (and still haven’t shared with you despite your longing for the delicious tastes of their grandma’s perogies). Shuffling the containers around, you reach into the back to pull out a packet of the glorious, almighty: PIZZA POP (or Hot Pockets for all of my friends down south in the U.S.). Right now it’s just a hard shell of pre-cooked dough which encases a blob of tomato sauce, assorted meats and bits of cheese, but in about 2 minutes and 38 seconds, it will become a feast worthy for a queen a queen that has bedhead hair and rumpled PJs.

https://giphy.com/gifs/asian-microwave-pizza-pop-3ohs4vkalS3hHNk68E

You feel your way to the metal box that will make your pizza-filled dreams come true. Jabbing the lower right corner pops open the door to a brightly lit interior stained with mystery sauces from other late night stumblings. As the light blinds your precious eyes, you plop the pizza pops in (after removing them from their plastic wrapper of course) and slam the door shut, press the defrost button, and wait. The whirring starts, the pizza pops rotate, and you bask in the invisible waves emanating from the box. “Ding!”–goes the timer! Out comes the pizza pop, and straight into your mouth it goes: where it simultaneously burns the roof of your mouth and places a still-frozen chunk of cheese on your tongue. The queen is satisfied, albeit with a burnt mouth. And to think that this magical, instantaneous meal was all possible due to a man named Peter Spencer.

History of the Microwave

Let’s travel back in time to the era of WWII. At the end of the war, there was an excess of cavity magnetrons, machines that generated the short-wave radar for the US military. The company Raytheon wanted to find another use for them (so that they wouldn’t go to waste), and thus researchers like Peter Spencer were employed to see if the magnetrons could be repurposed into something new. During the testing of several new magnetrons, Peter noticed that the candy bar in his pocket started to melt. Although other companies such as GE and Westinghouse had been working on microwave technology to cook food (Westinghouse even used a 10-kilowatt radio transmitter to cook steak and potatoes placed between two metal plates!), there hadn’t been much progress. Peter tested the magnetron’s cooking power by using it to popcorn and explode eggs and finally encased it in a metal box to trap the waves. Thus, the first microwave oven was born [1].

Behold, a magnetron! (https://en.wikipedia.org/wiki/File:Magnetron_cutaway_drawing.png)

 When you think about it, it’s amazing how we can take such a complex piece of machinery for granted. What had been a heavy, bulky contraption in the 1940s has now become a sleek box that can cook up whatever we desire! But then we come to that burning question which will be the focus of this post: how does it work? The answer lies in the full name: the microwave oven. An oven that uses microwaves to cook food.

We live in amazing times y’all https://giphy.com/gifs/ad-1970s-microwave-xUOwG6KvcukJRt5Cxy

How Microwaves Work

We cook our food by applying heat, and this heat transfer can occur in many ways: 1) through contact with a hot pan (conduction), 2) by the movement of hot air in an oven (convection), or 3) by microwaving your food (radiation). The microwaves create an alternating electromagnetic field inside the oven, causing the electric dipoles of polar molecules to align with the field. The field rapidly alternates, forcing the molecules to reorient themselves in the changing field. This causes the molecules to vibrate faster, meaning that it generates heat, and the temperature of the material rises [2].

You know what’s a polar molecule? Water!

You also know what’s a common molecule found in foods? Water!

I think you can see where I’m going with this…

The heat generated by the vibrating water molecules in your food is how your pizza pop transforms from an icy block into a soft, delicious treat. While cooking your food in an oven or on the stove exposes only the outside to the heat (and thus the food heats up from the outside towards the center), cooking your food in a microwave heats it throughout the entire mass simultaneously due to the distribution of water throughout the mass.

STOP. HOLD UP. IF MY PIZZA POP IS SUPPOSED TO HEAT UP EVENLY THROUGHOUT THE ENTIRE POP, THEN WHY DO I STILL GET CHUNKS OF FROZEN CHEESE AND BLOBS OF TOMATO LAVA IN THE SAME POP?

Well, this is where we come to the downsides of microwaves.

Here is a gif of an alternating microwave in a microwave oven.

https://giphy.com/gifs/waves-microwave-3ohs4oLRFFQmiv0YAE

Notice how some areas get to experience the peaks and valleys of the wave (the anti-nodes, creating hot spots), while the purple dots are the nodes of the wave and thus are the cold spots. This is why many microwaves have rotating floors, to ensure more even cooking [3]. Alas, there will be times where you’ll still end up with cold chunks inside your pizza pop, especially if there are large pieces of ice in your product. Ice cannot absorb microwaves as well as liquid water and combined with the higher amount of energy needed to melt ice into water, this can contribute to those lingering cold spots in your food [4].

Another downside of microwave oven cooking is that you’re not going to get that lovely, dark brown crust that occurs from Maillard browning. Since microwaves are mainly heating the water in your food, the temperature of your pizza pop won’t really rise past 100C/212F. Maillard browning is more rapid at higher temperatures, like when we’re sauteing onions in a frying pan or roasting a turkey in an oven. You may notice that there are frozen foods being sold with sleeves that have a metallic lining on the inside. The metallic lining heats up to temperatures significantly higher than the water as a way to brown the top of your bistro pocket. Not as ideal as your oven but at least you get hot food with slight browning in under 3 minutes [5].

WAIT I THOUGHT YOU CAN’T PUT METAL IN THE MICROWAVE OTHERWISE IT’LL BLOWUP. WHAT’S THIS METALLIC LINING BUSINESS?

Well, you’re right, if you leave your fork in your bowl of pasta when you microwave it, you’ll probably ruin your microwave. Since metal conducts electricity well, electrons will pile up on the edges of any pointy parts of your metal (like for example, the tines of a fork). The buildup results in arcs of electricity between the tines (and subsequently the death of your microwave). Food manufacturers know this and that’s why they produce those crisper packets with only a small amount of aluminum for maximum browning and minimal fires [6]. Those crisper packets contain a smooth and flat sheet of aluminum foil encased in a cardboard sleeve so that there are no exposed edges or crinkles in the foil for electrons to gather and create sparks. As long as you heat up your food for the recommended amount of time, you’ll keep your oven and your food safe and free from incineration [6].

https://giphy.com/gifs/funny-fire-microwave-OqDXby6tnVv5Tg4ZfL

(For those of you who get excited by setting things on fire, you can make a plasma ball in your own microwave just from a grape cut in half! We at Science meets Food and IFT do not endorse any behavior that may cause the loss of your life, home, and microwave. Link to video )

https://giphy.com/gifs/life-real-over-as2mwROqCINz2

Microwaves have also been used in research as a method to prepare samples for chromatographic analysis. Typically, researchers would have to use various methods of extraction (like pouring boiling petroleum ether over the sample or shaking the sample in methanol) in order to separate out the desired compounds into the solvent. These methods can use up a lot of resources and are time-consuming. Researchers like Ganzler et al found that microwave irradiation of food and feed samples in a small amount of methanol, for seven cycles of 30 seconds, led to a higher yield of polar compounds from the sample than traditional Soxhlet extraction [7]. Not only can food chemists speed up their analyses, having a greater yield of their desired compound also leads to more accurate results. Microwave extraction has also been successfully used to extract bioactive compounds such as phenolics and flavonoid compounds, from the pulp and peels of processed fruits and vegetables [8]. Like with Ganzler et al., the extraction procedure involves putting the pulp/peels/seeds into a small amount of solvent and microwaving it for several short bursts of time. This opens up the potential to take food waste and reuse it into a source of nutritional potential, by extracting out the bioactive compounds to fortify our food (and in my opinion, the more we can reduce food waste, the better it is for our economy and our environment).

The microwave is an extraordinary, small box that can transform your frozen dinners into tasty meals in minutes, and now you know a little more about how a microwave works.  While the process of microwaving food may still seem incredible, or even dangerous, the microwave oven has been proven to be safe for decades [9].  Don’t worry if skeptics say that microwaves create radiation in food or give you cancer; microwaves do little more than cause vibrations in your food to heat things up and there’s no evidence that microwaved food can harm you.  So with that in mind, maybe the microwave isn’t that magical anymore.

Actually never mind I found out that you can make MUG CAKES IN A MICROWAVE!!!

I TAKE MY WORDS BACK THE MICROWAVE IS MAGICAL. Here’s a recipe for a delicious mug cake so you can also taste the magic!

https://giphy.com/gifs/dessert-J7GI5QzYq9y3C

Ackerman, Evan. 2016. “A Brief History of the Microwave Oven – Where the ‘Radar’ in Raytheon’s Radarange Came from.” Spectrum IEEE (blog). September 30, 2016. https://spectrum.ieee.org/tech-history/space-age/a-brief-history-of-the-microwave-oven .

“q & a: how do microwaves work” 2011. physics questions ask the van (blog). november 3, 2011. https://van.physics.illinois.edu/qa/listing.phpid=821 ., foley, alexandra. n.d. “why does a microwave heat food unevenly” comsol multiphysics© (blog). accessed february 12, 2018. https://www.comsol.com/blogs/why-does-a-microwave-heat-food-unevenly/ ., chaplin, martin. 2017. “water and microwaves.” water structure and science. november 6, 2017. http://www1.lsbu.ac.uk/water/microwave_water.html ., jaeger, h., a. janositz, and d. knorr. 2010. “the maillard reaction and its control during food processing. the potential of emerging technologies.” pathologie-biologie 58 (3): 207–13. https://doi.org/10.1016/j.patbio.2009.09.016 ., “mit school of engineering | » why can’t we put metal objects in a microwave” n.d. mit engineering (blog). accessed february 12, 2018. https://engineering.mit.edu/engage/ask-an-engineer/why-cant-we-put-metal-objects-in-a-microwave/ ., ganzler, katalin, andrás salgó, and klára valkó. 1986. “microwave extraction.” journal of chromatography a 371: 299–306. https://doi.org/10.1016/s0021-9673(01)94714-4 ., routray, winny, and valérie orsat. 2012. “microwave-assisted extraction of flavonoids: a review.” food and bioprocess technology 5 (2): 409–24. https://doi.org/10.1007/s11947-011-0573-z ., “microwave ovens do not cause cancer.” 2014. cancer council nsw. january 15, 2014. https://www.cancercouncil.com.au/86089/cancer-information/general-information-cancer-information/cancer-questions-myths/environmental-and-occupational-carcinogens/microwave-ovens-do-not-cause-cancer/ ..

Science Meets Food

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Hello, Thanks for sharing such wonderful information with us very interesting and informative very helpful keep up the good work.

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How does a microwave heat your food? Water interacting with high-frequency electromagnetic waves.

There’s no open flame, no red-hot burner, no glowing oven coil. So how does a microwave invisibly cook your food? The answer: water.

Water is found in the tissues of all plants and animals. High-frequency electromagnetic waves produced by the microwave stimulate the water inside and heat the food.

The atoms in water molecules carry tiny electrical charges. The oxygen atom exhibits a partial negative charge and hydrogen atoms exhibit a partial positive charge. As the microwave bombards the food, it stimulates electrons. Water molecules continually attempt to reorient themselves so that their positive side faces the negatively charged electrons. This constant reorientation produces the rotation of the water. Rotation and agitation of the water molecules generates friction, which produces heat and warms your food.

To better understand, play with the single water molecule and electron here.

Instructions

• Click and drag the yellow electron to move it around the water molecule, made of two hydrogen atoms (red) and an oxygen atom (blue) .
• See how movement of the electron with its negative charge forces the water molecule to rotate as its positively charged hydrogen atoms are attracted to the electron.

Science in School

Microwave experiments at school teach article.

Author(s): Halina Stanley

Halina Stanley introduces a number of spectacular classroom experiments using microwaves.

As reported in this issue of Science in School ( Stanley, 2009 ), Israeli scientists have been using microwaves to drill holes into glass and ceramics, and to produce plasma balls. Microwave ovens are a useful resource for teachers as well as scientists. Here is a collection of fun microwave experiments that are suitable for the classroom.

Plasma balls

Using a microwave oven, you can create balls of plasma w1 at school from nanoparticles of soot. Dr Chris Schrempp, who teaches at a Californian high school, has been doing this in class for some time. He says, “This is a great demonstration that is always a sure hit with students of any level. Although the owner of the participating microwave, if present, will be absolutely sure that the appliance will be a total loss after the demonstration, it should remain surprisingly undamaged.”

• A small heatproof glass bowl
• A short wooden splint or toothpick (3-5 cm long)
• 50 ml laboratory beakers (or other similarly sized microwavable objects)
• Remove the turntable from the microwave and cover or remove the light.
• Stick the wooden splint or toothpick into the cork.
• Support a small heatproof glass bowl upside-down in the centre of the microwave using a circle of beakers. The bowl should be raised high enough that the toothpick stuck in the cork can be placed beneath it.
• Pre-program the microwave for 30 seconds at full power and turn off the lights in the room.
• Light the splint and put it into the microwave under the glass bowl.
• Close the door and turn the microwave on.

The plasma usually forms in about 10 seconds. Schrempp says, “It will make a horrific noise, sounding as though the microwave is frying from he inside out.” If a plasma ball does not form in this time, stop the microwave, relight the splint and start again.

Safety note:

 The microwave should only be allowed to run for about 20-30 seconds, otherwise the glassware might overheat and break. Be sure not to let the toothpick burn right down and set fire to the cork.

The inverted glass bowl serves to contain the plasma so that it can be viewed through the window easily. The demo can be performed without the bowl, but the fireball will then rise to the top of the microwave, so you have to bend down and look up into the window to see it.

The only negative effect of the demonstration is a smoky smell in the microwave. Schrempp says he has never had any real damage to the oven, just some sooty marks, but suggests that an older oven be used just in case.

Schrempp’s demonstration of this and lots of other dramatic experiments can be seen on the Exploscience website w2 .

Plasma balls can also be created using grapes, as described in Schrempp’s e-book Bangs, Flashes, and Explosions – An Illustrated Guide of Chemistry Demonstrations w3 :

• Cut a grape almost completely in half along its length, retaining a small piece of the skin on one side to keep the two halves connected.
• Place the grape on a dish, cut side up, and put it into the microwave.
• When the oven is turned on, plasma will be emitted from the section of skin connecting the two halves.

A video of the grape plasma can also be found online w4 .

Soap sculpture

When microwaved on full power for about a minute, a bar of soap grows into a strange volcanic lava, or something that looks like horrible fungus. The deformation is caused by tiny pockets of water in the soap vaporising, or by air in the soap expanding as it heats up.

The soap sculpture may leave the microwave oven (and the classroom) smelling quite strongly, so try to find non-perfumed soap and avoid doing this in a microwave that is used to prepare food. This demonstration has the added benefit that the teacher can leave the microwaved soap lying around the science preparation lab at school to worry colleagues, or the students can take it home to perturb members of their family.

This and other experiments can be found on the physics.org website w5 .

Eggy explosions

If demonstrations are good, explosions are unforgettable. My children will never let me forget the night my son’s boiled egg had a rather runny white and I said, “a few seconds in the microwave will just finish it off nicely”! A hen’s egg, even with the top cut off, will explode dramatically when heated in a microwave. You can try it in a lesson, but only if you’re prepared to clean the inside of the microwave afterwards!

A US TV programme, Brainiac Science Abuse, has taken this experiment to the logical limit by microwaving an ostrich egg. This is probably not an experiment that you will want (or be able) to do yourself, but there are many versions of it on YouTube w6 . I strongly suspect that the experiment was rigged in some way (they call it science abuse ), but you could use the video to wake up any class.

Light bulbs

Another classic demonstration is to put a light bulb in a microwave oven. An incandescent light bulb (whether or not it is still functional) will light up when irradiated with microwaves, provided the glass is intact. Depending on the type of bulb, you can get different colours. Remember that the bulb will heat up very quickly; 10 seconds is probably long enough before allowing it to cool down again.

Fluorescent tubes will also light up, and the effect can be used to test for microwave leakage around the doors of microwave ovens. Switch on the microwave and hold a fluorescent tube against the edges of the oven door. If the microwave leaks, it will make the bulb glow. (Switch off the lights in the room so that you can see the glow.) This works much better if the oven is empty, but if you’re testing an older (pre-1980s) oven, you might want to include a glass of water. Note that this method only shows the larger leaks.

This and other facts, myths and experiments about or with microwaves are collected on William Beaty’s website w7 .

Measure the speed of light with bread and margarine

The ‘naked scientists’ Chris Smith and Dave Ansell describe a very nice demonstration using standing waves to calculate the speed of light microwaves in their book Crisp Packet Fireworks and on their website w8 , where you will also find further microwave and other experiments.

Having been taught all about the really difficult historical experiments to measure the speed of light, students think it is great to use this easy method. The only drawback of this demonstration is a rather strong smell of toast. This experiment can also be used to reinforce the notion that all waves in the electromagnetic spectrum travel at the speed of light.

• A plate (and possibly a bowl)
• Four pieces of toast
• A buttering knife
• Remove the turntable from the microwave.
• Arrange four pieces of toast in a square shape on a plate.
• Cover them completely with margarine, making sure to include the joints where the pieces meet.
• You need to ensure the plate won’t turn when you switch on the microwave. If there is a central pillar supporting the turntable, you may cover it with a bowl turned upside down and balance the plate on top of it.
• Switch on the microwave at full power for 15 – 20 seconds until the margarine just begins to melt. Powerful microwaves may need less time, so check every 5 seconds. Be very careful not to microwave for too long.
• You should see a series of parallel melted patches or lines separated by unmelted patches. Take out the plate.
• Measure the distance in centimetres between two of these patches with a ruler. Multiply by two and note down the value: this is the wavelength of the microwaves produced by your oven – it should be around 12–12.5 cm.
• Now you need to find out the frequency of the microwaves. You should be able to find it on a sticker, usually at the back or door lip of the microwave. If you can’t find the specific value of your microwave, use 2450 MHz (2.45 GHz) as a standard value.
• Multiply the wavelength (about 12 cm) by the frequency. If you are using MHz, you’ll need to multiply the result by one million, with GHz by one billion.
• The result will be the speed of light in centimetres per second. Divide it by 100 to convert it to metres per second. Your answer should be about 300 million metres per second.

Light, including microwaves, is a wave consisting of a series of peaks and troughs. The wavelength is the distance from one peak or trough to the next. The frequency is the number of waves per second. To know how fast a wave is travelling, you need both values.

A microwave oven produces waves on one side of the oven, which are reflected on the opposite side and return to where they started. The reflected waves will encounter the original waves, cancelling each other out in some places, while adding up in others: the waves bouncing about in the oven interfere with each other, creating a standing wave with positions of high amplitude (antinodes) where there will be strong heating, and positions where the amplitude is close to zero (nodes) where there will be little heating. The distance between two hot spots is half a wavelength – the distance from one antinode to the next. In these hot spots, the margarine will melt first.

• Stanley H (2009) Plasma balls: creating the 4th state of matter with microwaves. Science in School 12 : 24-29. www.scienceinschool.org/2009/issue12/fireballs
• Smith C, Ansell D (2008) Crisp Packet Fireworks. London, UK: New Holland Publishers

Web References

• The Internet Plasma Physics Education Experience website: http://ippex.pppl.gov/fusion/fusion3.htm
• The glossary on the Southwest Research Institute website: http://pluto.space.swri.edu/image/glossary/plasma.html
• The Fusion Energy Division of the Oak Ridge National Laboratory: www.ornl.gov/sci/fed/Theory/tt/ttmcp/plasma.htm
• The FusEdWeb (fusion energy education) website: http://fusedweb.llnl.gov/cpep/Chart_Pages/5.Plasma4StateMatter.html
• w2 – The Exploscience website has many videos of dramatic experiments: www.exploscience.com/ChemTV_Page_5.html
• w3 – Chris Schrempp’s e-book, Bangs, Flashes, and Explosions – An Illustrated Guide of Chemistry Demonstrations , a manual with over 170 chemistry demonstrations and activities, can be ordered here: http://exploscience.com/Book.html
• w4 – The grape plasma can also be seen on the Naked Scientists website ( www.thenakedscientists.com ) or here: http://tinyurl.com/mklx73
• w5 – The physics.org website has many fun experiments and games: www.physics.org/interact-wide-template.asp
• w6 – For a dramatic demonstration of microwaving an ostrich egg, see: http://www.youtube.com/watch?v=Wgy1Yhgk_BY
• w7 – William Beaty’s ‘Unwise microwave oven experiments: high voltage in the kitchen’ website contains facts, myths and experiments about or with microwaves: http://amasci.com/weird/microwave/voltage3.html
• w8 – You can find the margarine experiment, and much more, on the Naked Scientists website ( www.thenakedscientists.com ) or here: http://tinyurl.com/lhdk7r
• The UK’s Institute of Physics describes a number of experiments involving microwaves on its website: www.iop.org/activity/education/Projects
• Mobile phones transmit and receive using microwave radiation – either 900 MHz or 1800 MHz – similar to the frequency of the radiation in a microwave oven (2450 MHz). The UK’s Science Enhancement Programme has some very useful documents on radiation in the environment, including background information and student activities. See: www.sep.org.uk/teacher/view_resource.asp?resource_id=20

Halina Stanley is a physicist by training. She spent ten years as a research scientist in industry and academia using neutron and X-ray scattering techniques to characterise materials before joining the American School of Grenoble, France, where she teaches physics, chemistry and mathematics to secondary-school children.

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May 16, 2013

Soapy Science: How Microwaves Affect Matter

Suds up with this super-clean science activity from Education.com

By Education.com

Key concepts Microwave Radiation Heat Chemical Polarity Dipole Rotation

Introduction Ever wonder how a microwave oven cooks your food? A microwave uses—you guessed it!—microwaves, a form of high-frequency electromagnetic radiation. Think radio waves, just with a much shorter wavelength. Here's the cool thing about microwaves: They're absorbed by certain kinds of matter, whereas other kinds are left alone. In this activity, we'll try cooking up some foamy soap in order to illustrate how microwave radiation influences different types of matter.

Background Soap is a handy combination of chemicals that do some very cool things when you use it. Soap molecules have both a polar and a nonpolar part. What' is polarity? A molecule is described as polar when it has two or more areas of different electrical charges. A water molecule is a perfect example: it has a negative pole created by the negative charge its oxygen atom and a positive pole created by the positive charges of its two hydrogen atoms.* By having a polar and a nonpolar part, soap can bind to both water and dirt. This is what makes it such an effective cleanser!

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Microwave ovens work by causing molecules that have two opposing poles to spin rapidly. Because of their polarity, molecules like water will constantly align themselves with a magnetic field they're subjected to. Microwave radiation creates a magnetic field that oscillates—which means that the field is constantly changing its orientation (direction the positive and negative charges face). Those shifts make polar molecules like water start spinning as they try to keep up with the changing charges. As the molecules spin, they generate heat. This process is known as dipole rotation. ("Dipole" simply means "having two poles.")

Have you ever used a microwave to boil water and found yourself wondering why the air in the microwave doesn't get hot like the air in a conventional oven? Microwave radiation causes water molecules go nuts, but the air itself isn't directly heated because its molecules aren't as polar as the molecules that make up water. This help explains why you can't make a pie's crust crispy in the microwave,* but it's easy to burn one to oblivion in a conventional oven! Polarity also explains why many plastics, glasses and ceramics are considered "microwave safe"—their molecules in these substances aren't very polar, so they aren't as disturbed by the magnetic fields shifting.

Materials • One bar Ivory brand soap • One bar Dial soap • Two paper plates • Microwave

Preparation • Note the weight of each bar of soap, which should be written on the packages. • Unwrap each bar. • Place each on a paper plate, noting which one is which.

Procedure • Microwave the Ivory soap for two minutes, carefully observing it during the whole time. What happens to the soap? Why do you think this might occur?  • Remove the plate with the soap from the microwave. Use caution, as it may be hot. • Microwave the Dial soap for two minutes, carefully observing. Does this soap react differently than the first one? Why do you think this might be? • Again, be careful when removing the heated plate. • Extra: Before microwaving, weigh each bar of soap. Which is heavier? If one is heavier than the other, what do you think accounts for this difference, besides size? Do you think this might help to explain what we saw when we "cooked" the soap bars in the microwave? Observations and results The Ivory soap should have produced an impressive amount of foam compared with the Dial. Ivory has thousands of tiny air pockets in it—that's why it should have weighed less! These pockets of air expanded when they got hot, creating the soap bubbles that made up our foam.

But what caused the air to get so hot in the first place? As we discussed, microwave ovens are pretty bad at heating air. But part of our soap molecules are polar, so the microwave radiation caused these molecules to spin and build up kinetic energy, which created heat. This resulting heat was conducted from the melting soap to the air pockets, causing the pockets to expand and create some impressive foam.

More to explore: Foaming Soap , from Education.com Microwave Madness , from Education.com Exploding Marshmallows , from Education.com Chemical Polarity , from Wikipedia

This activity brought to you in partnership with  Education.com *Editor's note (May 30, 2013): These sentences were edited after posting either to correct or clarify the original content.

Top 50 Fun Food Science Experiments

Welcome to our carefully curated compilation of the top 50 food science experiments especially created for curious students and budding young scientists.

Are you ready to embark on a mouth-watering journey where science meets deliciousness? We’ve handpicked a collection of fascinating experiments that will tickle your taste buds and ignite your curiosity.

Edible Food Science Experiments

Edible food science experiments offer a delicious and engaging way for students and teachers to explore scientific principles in a hands-on and memorable manner.

By combining the fascinating world of food with the principles of chemistry, biology, and physics, these experiments provide a unique avenue for learning.

1. Magical Color Changing Unicorn Noodles

Get ready to enter a world of whimsy and enchantment with this captivating food science experiment: “Magical Color Changing Unicorn Noodles!”.

Learn more: Magical Color-Changing Unicorn Noodles

2. Glow in the Dark Jello

Prepare to be amazed and mesmerized by the enchanting world of “Glow in the Dark Jello!” Calling all curious minds and lovers of luminescence, this food science experiment will take you on a journey into the realm of bioluminescence and chemistry.

Learn more: Glow in the Dark Jello

3. DIY Soil Layers

Get ready to dig deep into the fascinating world of soil science with this captivating food science experiment: “DIY Soil Layers.”

This hands-on project will take you on a journey of exploration as you unravel the intricate layers that make up the foundation of our planet’s biodiversity.

4. Solar Oven

By building and using a solar oven, students will unlock the secrets of heat transfer, insulation, and sustainability. Witness the incredible transformation of sunlight into cooking power as you prepare delicious snacks with the sun’s energy.

Learn more: Solar Oven ]

5. Oreo Moon phase

This experiment not only offers a delightful treat for your taste buds but also introduces you to the fascinating study of astronomy and celestial phenomena.

6. Lava Toffee

Get ready to ignite your taste buds and witness a molten spectacle with this thrilling food science experiment: “Lava Toffee!”.

Calling all daring confectionery explorers and lovers of sweet surprises, this hands-on experience offers a fusion of culinary creativity and scientific discovery.

7. Fizzy Lemonade

This experiment is your ticket to becoming a beverage alchemist as you explore the science behind creating the ultimate fizzy lemonade.

8. DIY Home-made Ice Cream in a Bag

“Homemade DIY Ice Cream in a Bag!” Calling all students with a passion for dessert and a curiosity for science, this is an experiment you won’t want to miss.

9. Turn Milk into Cheese

“Turn Milk into Cheese!” If you’ve ever wondered how that creamy goodness makes its way from the farm to your plate, this is your chance to unlock the secrets of cheese making.

Learn more: Turn Milk into Cheese

10. Bread in a Bag

This experiment not only allows you to explore the science behind bread fermentation and yeast activation but also provides an opportunity to develop essential kitchen skills and creativity.

11. Edible Water Bottle

This experiment not only provides a practical solution to the global plastic pollution problem but also introduces you to the principles of food science and sustainable packaging.

12. Home-made Butter

Prepare to be amazed as you transform a simple ingredient into a creamy, spreadable delight right in the comfort of your own kitchen.

By participating in this experiment, students will not only discover the mesmerizing process of butter making, but also gain a deeper understanding of the science behind it.

13. Rock Candy Geodes

This experiment offers a delectable treat for your taste buds and introduces you to the fascinating world of minerals and crystal formation.

14. Make a Fizzy Sherbet

Get ready for a fizzy and flavorful explosion with this exciting food science experiment: “Fizzy Sherbet!” Calling all taste adventurers and fizz enthusiasts, this experiment is sure to tickle your taste buds and ignite your curiosity.

Learn more: Make a Fizzy Sherbet

15. Meringue Towers

This experiment not only allows you to explore the science behind meringue’s unique texture and stability but also provides an opportunity to develop your creativity and precision in the kitchen.

Learn more: Meringue Towers

16. Mug Cake

Students, this is your chance to dive into the fascinating world of culinary chemistry as you explore the principles of ingredient ratios, microwave heat transfer, and the science behind cake rising.

Learn more: Magic Mug Cake

17. Apple Experiment

This experiment not only stimulates your senses but also encourages critical thinking, data analysis, and creativity. So, grab your lab coats, sharpen your taste buds, and let the apple experiment take you on a journey of scientific discovery.

18. Grape Molecule

This hands-on experience not only allows you to engage with the principles of chemistry and molecular structure but also stimulates your creativity as you craft your own grape molecule masterpiece.

Learn more: Grape Molecule

19. Kitchen Chemistry

Get ready to mix, bake, and discover the magic of chemistry in the kitchen with this exciting The Kitchen Chemistry Cake Experiment!.

Calling all aspiring bakers and science enthusiasts, this hands-on experience offers a delectable blend of culinary art and scientific exploration.

Learn more: Cake Experiment

20. Sugar on Snow

This experiment not only offers a delicious sensory experience but also teaches you about the principles of heat transfer and phase changes.

21. Fibonacci Lemonade

As you pour and observe the layers of the Fibonacci Lemonade forming, you’ll gain a deeper appreciation for the harmonious relationship between science and art.

Learn more: Fibonacci Lemonade

22. Edible Glass

By combining simple ingredients and a touch of creativity, you’ll transform ordinary kitchen materials into a stunning and edible glass-like creation.

Learn more: Edible Glass

23. Edible Igneous Rocks Experiment

As you shape and mold the ingredients into rock-like structures, you’ll gain a deeper understanding of the volcanic processes that shape our planet. So, grab your materials, don your lab coat, and let’s embark on this delectable geological adventure.

Non-Edible Food Science Experiments

Prepare for a non-edible food science adventure that will ignite your curiosity and challenge your scientific prowess! These experiments will unlock the secrets of chemical reactions, physical properties, and the wonders of scientific exploration.

24. Magnetic Cereal

Prepare to be magnetized by the captivating world of “Magnetic Cereal!” This fascinating food science experiment will take you on a journey of discovery as you explore the hidden magnetic properties of your favorite breakfast cereal.

Learn more: Magnetic Cereal

25. Lemon and Battery

As you observe the lemon-powered circuit in action, you’ll gain a deeper understanding of the science behind electrical conductivity and the role of acids in generating power.

Learn more: Lemon and Battery

26. Milk Swirl Experiment

Prepare to be mesmerized by the enchanting “Milk Swirl Experiment.” This captivating food science exploration will take you on a journey through the mysterious world of surface tension and molecular movement.

Learn more: Milk Swirl Experiment

27. Bouncy Egg

Get ready for an egg-citing and egg-ceptional food science experiment: “Bouncy Egg!” Prepare to witness the incredible transformation of a fragile egg into a resilient and bouncy marvel.

Learn more: Bouncy Egg

28. Extracting Strawberry DNA

Through this hands-on exploration, you’ll develop a deeper understanding of the structure and function of DNA, as well as the importance of DNA in all living organisms.

29. Lemon Volcano Experiment

Calling all budding scientists and lovers of all things sour, this lemon volcano experiment is sure to leave you awestruck.

Learn more: Lemon Volcano Experiment

30. Electric Cornstarch

As you observe the cornstarch mixture respond to the electric current, you’ll gain a deeper understanding of the properties of matter and the interactions between electricity and materials.

31. Pop Rock Science

This hands-on experience not only offers a delightful sensory experience but also allows you to explore the principles of gas production, pressure, and the science of effervescence.

Learn more: Pop Rock Science

32. Frost in a Can

By using simple household materials, you’ll create your very own mini frost chamber that will transform warm air into a breathtaking display of frost.

33. Hopping Corn

Get ready to witness a popping and colorful spectacle with this captivating Hopping Corn experiment. This hands-on experience combines the excitement of popcorn popping with a twist of chemical reaction.

Learn more: Hopping Corn

34. Digestive System Experiment

Using a plastic bag filled with water, bread, and calamansi juice, you’ll witness firsthand how our bodies break down and extract nutrients from our food.

This experiment visually represents the digestive process and introduces you to our digestive system’s intricate workings.

Candy Science Experiments

Sweeten your curiosity and unleash your inner scientist with the thrilling world of Candy Science! Brace yourself for an explosion of flavors, colors, and mind-bending experiments that will leave you craving for more.

35. Skittles Rainbow

Prepare to unlock the secrets behind the mesmerizing phenomenon of color diffusion as you witness the magic of Skittles turning water into a vibrant rainbow.

Learn more: Skittles Science Fair Project

36. Home-made Fruit Gummies

By combining fresh fruit juices, gelatin, and a touch of sweetness, you’ll create your mouthwatering gummy treats bursting with fruity flavors.

This experiment not only allows you to customize your gummies with your favorite fruits but also allows you to understand the principles of gelatinization, texture formation, and the chemistry behind gummy candies.

Learn more: Home-made Fruit Gummies

37. Candy DNA Model

Get ready to unlock the sweet secrets of life with this fascinating Candy DNA Model food science experiment. This experiment offers a delicious and hands-on approach to understanding the fundamental structure of DNA.

Learn more: Candy DNA Model

38. Gummy Bear Science

This experiment is a sweet and chewy opportunity to uncover the fascinating world of polymer chemistry and osmosis.

By immersing these beloved gummy treats in different solutions, you’ll witness the mesmerizing process of gummy bear growth and shrinkage as they absorb or release water.

Learn more: Gummy Bear Science

39. Candy Camouflage

In this exciting activity, your favorite M&M candy colors represent different predators in a simulated ecosystem. Your task is to pick the right candy color that will allow you to survive and thrive.

40. How to Make Sedimentary Rocks

This experiment not only provides a creative outlet for your imagination but also introduces you to the fundamental principles of geology and rock formation.

41. Home-made Fluffy Marshmallow

Grab your mixing bowls, roll up your sleeves, and let’s dive into the world of homemade fluffy marshmallows. Join us on this marshmallow-filled adventure and let your taste buds soar to sugary heights

Learn more: Home-made Fluffy Marshmallows

42. Making Lollipops

This experiment not only allows you to explore the principles of sugar crystallization, temperature control, and the art of candy making but also encourages imagination and sensory exploration.

Learn more: Making Lollipops

43. Candy Chromatography

Get ready to unravel the colorful secrets of candy with this captivating Candy Chromatography experiment. This experiment will take you on a journey into the fascinating world of chromatography.

Learn more: Candy Chromatography

44. Dancing Worms

As you observe the worms twist, turn, and wiggle in response to their environment, you’ll gain a deeper understanding of how living organisms interact with their surroundings.

Learn more: Dancing Worms

45. Candy Atom Models

This hands-on experience offers a unique opportunity to explore the building blocks of matter in a fun and tasty way.

By using a variety of candies as representations of atoms, you’ll construct colorful and edible models that bring chemistry to life.

Learn more: Candy Atom Models

46. Kool Aid Rock Candy

Join us on this delicious and educational adventure, and let your taste buds and curiosity be delighted by the crystalline wonders of science. Get ready to taste the magic and witness the sweet transformation of sugar into dazzling rock candy crystals!

47. Starburst Rock Cycle

This hands-on experience offers a unique and mouthwatering way to explore the processes that shape our planet.

Learn more: Starburst Rock Cycle

48. Toothpick Bridge

By engaging in this activity, students can gain valuable insights into the principles of structural engineering, including load distribution, stability, and balance.

Learn more: Toothpick Bridge

49. Candy Potions

Get ready to mix magic and science with the captivating world of candy potions! This delightful food science experiment allows students to explore the wonders of chemical reactions while having a sweet and colorful adventure.

Learn more: Candy Potions

50. Dissolving Candy Canes

Get ready to explore the fascinating world of candy chemistry with the mesmerizing experiment of dissolving candy canes! This simple yet captivating food science experiment allows students to learn about the concepts of solubility and dissolution.

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Improving the quality of vegetable foodstuffs by microwave inactivation

1 CJ Foods R&D, CJCheiljedang Corp., Suwon, Gyeonggi-do 16495 Korea

Myong-Soo Chung

2 Department of Food Science and Engineering, Ewha Womans University, Seoul, 03766 Korea

With the aim of improving the loss of quality in retorted vegetables, experiments on pretreatment inactivation using microwaves were carried out to allow the heating intensity to be reduced during retorting. Microwave heating reduced the bacteria level by 10 3 CFU/g, and was a more effective method considering the short processing time of 3 min and the required energy being 70–80% of that when using steam. The inactivation effect was due to dielectric heat generation by the high-frequency microwaves. The inactivation effect for heat-resistant Bacillus amyloliquefaciens was indicated by a reduction of 10 2 CFU/g after 3 min of microwave heating. The total bacteria counts for peeled potato and spicy sauce with vegetables decreased by 3–4 log CFU/g after 3 min using microwaves, and heat-resistant microorganisms were reduced by 2 log CFU/g. Combining microwave heating and mild retorting is expected to produce higher quality vegetable foodstuffs compared to conventional retorting.

Introduction

Various vegetables represent important materials in processed foods. But their weak structural characteristics during heating limit manufacturing methods to processes such as low-temperature heating, drying, and freezing so as to minimize the deterioration of sensory quality. Inactivation methods for vegetables based on heating include blanching for several tens of seconds at 100 °C and pasteurization for 10–30 min at 85 °C (Choi et al., 2018 ). But this type of mild heating makes it difficult to inactive the heat-resistance microorganisms that are associated with decreased organoleptic quality and safety. However, a loss of quality is inevitable when applying retorting at 121 °C to kill spores on vegetable foodstuffs (Gokhale and Lele, 2014 ; Kwak and Chang, 2001 ; Lee et al., 2012 ).

Hot-air drying is another widely used method for the long-term storage of vegetables. However, such drying is associated with various restrictions due to the generation of off-flavors, tough texture, and browning reactions (Hwang and Rhim, 1994 ). Freeze-drying at a low temperature can minimize the disadvantages of hot-air drying, but it results in a brittle structure and is more expensive than other methods. The quality of frozen vegetables is degraded during defrosting, and they are not convenient to store (Choi et al., 2015 ). Other inactivation methods such as adding natural antimicrobial agents including alcohol, organic acid, surfactant, calcium, and bacteriocin are relatively ineffective at controlling microorganisms, and their use is limited by the deterioration of taste, aroma, and color (Cho et al., 1994 ; Choi et al., 2018 ). Choi et al. ( 2013 ) reported on the use of ultrahigh pressure (a nonthermal inactivation method), but spores are not killed and can only be applied to refrigeration products such as sauces, jam, and processed meat and fish. In summary, the current processing and inactivation methods are not able to adequately control the levels of microorganisms in various vegetable foodstuffs while maintaining good quality, and so a new inactivation method is required that also exhibits the characteristic of a uniform temperature distribution.

One way to minimize excessive heating during sterilization is to reduce the retort conditions via pretreatment inactivation with microwave heating. Microwaves are used in the various food industries for cooking, pasteurization, drying, and thawing (Campañone et al., 2010 ; Chandrasekaran et al., 2013 ). Microwave heating occurs via dielectric loss due to the polarization of dipoles by electromagnetic waves with frequencies from 300 MHz to 300 GHz (Bae and Lee, 2010 ; Choi and Koh, 1993 ). In the case of foodstuffs, rapid internal heating due to the vibration of water molecules induced by microwaves can kill microorganisms with only a slight loss of sensory quality within a short time compared to conventional conduction heating. While the mechanism of microwave inactivation has been identified as microbial death by rapid dielectric heating at high frequency, the nonthermal inactivation effects of electromagnetic fields have not been clearly revealed (Curet et al., 2013 ; van Remmen et al., 1996 ). Previous studies of microwave inactivation have been restricted to applying pasteurization for pathogenic and spoilage microorganisms in chilled products, and the inactivation of enzymes (Bows, 2000 ; Kang et al., 2013 ). There have been few detailed studies of the important factors influencing microwave inactivation, such as the energy consumption, initial temperature, and physical properties of the foods and packaging materials (Knoerzer et al., 2007 ; Kwak and Chang, 2001 ).

As a result of considering the relevant research literature, there were relatively few studies on the sterilization of room temperature distribution foods using microwave heating. Therefore, the aim of the present study was to develop a novel technology for the inactivation of microorganisms in instant-cooking foods containing various vegetables and stored for a long time at room temperature, based on microwaves as a new heating method that can enhance the inactivation effect on heat-resistant microorganisms.

Materials and methods

The vegetables used as foodstuffs in sauces tested in this study, such as potato, carrot, onion, and red pepper, were purchased at a local market in Seoul, Korea. The samples were stored at 4 °C in a refrigerator to minimize any changes in quality such as taste, flavor, and appearance.

Microwave heating

Thermoduric bacteria that survive pasteurization at 63 °C for 30 min or 72 °C for 15 s are Bacillus , Clostridium , Microbacterium , and Micrococcus . Among these thermostable bacteria, Bacillus spp. is a soil-derived microorganism, which is present in many vegetables. The presence of heat-resistant bacteria in processed food products containing vegetables is important since they degrade the quality and present sanitary problems. Therefore, the inactivation effect of microwave heating against Bacillus amyloliquefaciens , which is a typical heat-resistant microorganism, was investigated.

To examine the inactivating effect of microwave heating in food material against heat-resistant bacteria, a 1-mL suspension of B. amyloliquefaciens was mixed with 110 g of sterilized soaked rice and 80 mL of distilled water in a sterilized transparent vinyl pouch made of PP (polypropylene) material, and then heated in a household microwave oven (RE-C21VW, 700 W, Samsung Electronics Co., Ltd., Seoul, Korea) with high frequency generation on three sides for 0, 3, 4, or 5 min.

In addition, unpeeled and peeled cubes (1.5 cm × 1.5 cm × 1.5 cm) of washed potato, and model foodstuffs such as sauces containing vegetables, spices, and seasonings were packed in a standing vinyl pouch with heat-resistance and heated by microwaves of 100 °C for 3 min. Potato is a typical vegetable used as a food raw material, and the main growth microorganism is a heat-resistant Bacillus spp. Considering this fact, potato was selected as a sample for inactivation experiment in this study. The temperature of the sample in the microwave oven was measured using a fiber optic temperature sensor (OPTOCON TS3, Weidmann Inc., Dresden, Germany ) , and used for setting of heating temperature and calculation of amount of heat generated.

Atmospheric and superheated steaming were used as control methods in this study at processing conditions of 100 °C for 20 min and 350 °C for 8 min, respectively. Superheated and atmospheric steaming were done in a superheated steamer (DFC-240W, Naomoto, Osaka, Japan) by adjustment of heating temperature and treatment time.

In the experiments, the temperature and time conditions on microwave and steam heating were determined through preliminary experiments. Each of the atmospheric steam, superheated steam, and microwave heating conditions applied to the experiment was firstly selected in consideration of the heating temperature and time range in which the characteristic flavor and color of the sample potato were not changed. Then, the final application temperature and time were selected considering the conditions that could be applied in the production line with commercialized equipment. The heating energy in microwave and steam heating was calculated by using the specific heat, mass and the temperature of the food materials. And the microwave energy was calculated by using output power of microwave oven and processing time.

Combination with retorting

In order to improve the quality of the retorted vegetables by reducing the heating intensity during retorting, the effect of combining pretreatment sterilization using microwaves and retorting was investigated in this study.

Retorting was performed after microwave heating using a pilot-scale, one-basket, water-cascading retort (Water Cascading Retort, Stock Pilot-Rotor 900, Hermann Stock Maschinenfabrik, Neumünster, Germany). A sterilization temperature of 121.1 °C and a steam pressure of 2.1 kg f /cm 2 were used in each experiment. Considering the temperature and time at which the vegetable base foods could reach the sterilized state, the retort conditions using the control were set at 121 °C for 20 min by preliminary experiment.

Each experiment was repeated at least five times, and the obtained data were subjected to statistical analysis. The temperature profile of the samples during each sterilization process were monitored using an F 0 sensor (TrackSense Prosensor, Ellab, Hilleroed, Denmark).

Measurement of microbial inactivation effects

The B. amyloliquefaciens strain was incubated on nutrient agar at 30 °C for 1 week. A suspension of cultured vegetative cells containing endospores was then collected by centrifugation (12,000× g for 2 min) and washed by repeated centrifugation/resuspension in sterile distilled water at 4 °C. Plastic cryopreservation tubes containing 1 mL of suspension (10 8 CFU/mL) were stored at − 70 °C until used. In general, Bacillus spp. that grows in vegetables is mixed with vegetative cell and endospore forming vegetative cell with heat resistance. Therefore, in the experiment, Bacillus spp. was prepared mixed type with vegetative cell and spore similar to actual environment.

The inactivation effect of microwave heating against B. amyloliquefaciens was measured using standard colony counting on tryptic soy broth agar (TSB, Difco Laboratories, Detroit, MI, USA) plates. And the inactivation effect of pretreatment in microwave heating was quantified based on the total bacterial growth on plate count agar (PCA, Difco Laboratories, Detroit, MI, USA) (Choi et al., 2018 ; Kwak and Chang, 2001 ). And heat-resistant bacteria were counted on trypticase soy agar (TSA, Difco Laboratories, Detroit, MI, USA) plates by analysis of total bacterial count after heating the ground sample mixed with sterile distilled water at 90 °C for 10 min.

Sensory evaluation

The organoleptic characteristics of the samples were determined by a trained panel such as 20 researchers who are in charge of processed food development. After completing three training sessions relate to descriptive profiling, hedonic testing, and perception, sensory attributes were evaluated based on the degree of overall acceptability of the treated potatoes and spicy sauce based on consideration of the taste, color, flavor, and texture. The panelists rated the preference of sensory attributes of each sample on a 5-point hedonic scale from 1 (extremely bad) to 5 (extremely good).

Statistical analysis

All of the data are expressed as mean and SD values of five replicate measurements. The significance of differences between the samples was assessed using analysis of variance and Duncan’s multiple-range test with Minitab software (MTB13, Minitab Inc., State College, PA, USA). The threshold for statistical significance was set at p  < 0.05.

Results and discussions

Microbial inactivation effect of pretreatment methods.

Methods of pretreatment inactivation using microwaves and steam were considered for improving the quality of heated vegetables by reducing the heating intensity in this study. The microwave and superheated steam heating methods, which have the advantages of rapid heating, were selected as effective pretreatment methods to avoid the excessive heat sterilization strength of retort which causes quality deterioration of vegetables. Peeled potatoes were heated with conventional atmospheric steam, superheated steam, and microwaves, for which the heating conditions were 100 °C for 20 min, 350 °C for 8 min, and 100 °C for 3 min, respectively.

The experimental results are shown in Fig.  1 . Each method showed an inactivation effect as a reduction of 10 3 –10 4 CFU/g in the total number of cells, and there were no marked differences in the inactivation efficacy between the pretreatment methods. All three methods produced a killing effect of 99.9–99.99%, which is statistically significant ( p  < 0.05) compared to the untreated control. From these experimental results, it can be seen that atmospheric steam, superheated steam, and microwave heating could be utilized as methods of pretreatment inactivation in retorting [Fig.  1 (A)].

Comparisons of the number of viable cells ( A ) and heating energy ( B ) for peeled potatoes when using steam or microwave heating. ST: no treatment, CS: conventional steam, SHS: superheated steam, MW: microwave heating, TC: total cell count, HR: heat-resistant microorganism. Bar data are mean and standard-deviation values; those marked with different letters differ significantly by ANOVA with Duncan’s multiple-range test at p  < 0.05

Though all three methods produced effective inactivation, microwave heating was a more sufficient method when considering the sensory quality, cost, and commercial applications associated with a short processing time of 3 min and the heating energy required being 70–80% of that when using steam [Fig.  1 (B)]. The reason that the heat energy was consumed low in the microwave heating as compared with the steam heating would be due to the rapid dielectric heating in the food inside by the high frequency vibration energy (Chandrasekaran et al., 2013 ; Park et al., 2017 ; Resurreccion et al., 2014 ). Therefore, the subsequent experiments were performed using microwave heating.

Inactivation by microwaves against heat-resistant bacteria

Bacillus amyloliquefaciens is a species of bacterium in genus Bacillus and α-amylase from B.   amyloliquefaciens is often used in starch hydrolysis. It is also a source of subtilisin, which catalyzes the breakdown of proteins. This enzyme activity originated from the B. amyloliquefaciens causes damages on the quality of processed vegetable foods, so B. amyloliquefaciens has been selected as a target microbial for inactivation in this study.

Microwave heating showed an inactivation effect of a reduction of 10 2 CFU/g after 3 min, but the killing intensity did not increase when the heating time was increased to 4–5 min (Fig.  2 ). Although this lengthening of the treatment time increased the applied thermal energy by 1.3- to 1.7-fold, it is assumed that the temperature of microwave heating did not rise above 100 °C and the inactivation effect does not increase all the time. This is because the microwave chamber is not in a sealed state where pressure can be applied during microwave heating.

Temporal changes in viable cell counts and microwave energy for heat-resistant B. amyloliquefaciens during microwave heating. “filled square”: heating energy. Bar data are mean and standard-deviation values; those marked with different letters differ significantly by ANOVA with Duncan’s multiple-range test at p  < 0.05

The vegetative cell of Bacillus spp. form endogenous spores when depleted of nutrients required for propagation, and have heat resistance that does not sterilize at 100 °C. Therefore, if the heat-resistant bacteria of Bacillus species capable of forming endogenous spores in vegetable foods can be killed in advance by pre-treatment, the heat sterilization conditions of retort for storage at room temperature can be alleviated and the sensory quality can be improved. And also, considering that the level of heat-resistant bacteria in processed foods from either the ingredients or contamination is typically 10 2 –10 3 CFU/g, the microwave heating could be applied as a pre-inactivation method for reducing the requirements of the retorting process (Lim, 1996 ; Luan et al., 2016 ).

In addition, if a sealed pressurized heating system capable of heating at high temperature and high pressure using microwave heating could be constructed, it will be possible to sterilize even heat resistant spores ( Malyshev et al., 2019 ; Park et al., 2017 ).

Microbial inactivation effect of microwaves on various foods

Peeled and unpeeled potatoes were heated by microwaves, respectively as representative samples for the detailed investigation of the inactivation effect on vegetables. The total bacteria counts of the peeled potato decreased by 3–4 log CFU/g after 3 min of microwave heating [Fig.  3 (A)]. This indicates that peeled vegetables can be completely sterilized by microwave heating. In the case of unpeeled potato, the total cell count was around 6 log CFU/g, and so 3 log higher than for peeled potato. This meant that a cell count of 3 log CFU/g remained after the 3 log reduction produced by 3 min of microwave heating [Fig.  3 (A)]. Regardless of whether the potato was peeled or unpeeled, the number of heat-resistant cells was reduced by 10 1 –10 2 CFU/g [Fig.  3 (B)].

Comparison of total number of viable cells ( A ) and number of heat-resistant viable cells ( B ) for potatoes and sauce with vegetables by microwave heating. ST: no treatment, TEST: microwave heating. Data are mean and standard-deviation values; those marked with different letters differ significantly by ANOVA with Duncan’s multiple-range test at p  < 0.05

The inactivation effect of microwave was caused by dielectric heat generation by the high-frequency energy (Lim, 1996 ; Pandit and Prasad, 2003 ; Zhu et al., 2018 ). The microwave heating of potatoes was associated with reductions in the deterioration of odor and discoloration, in addition to the excellent bactericidal effects. Moreover, microwave heating can control the moisture content and significantly ( p  < 0.05) improve the quality of processed potatoes compared to when using water blanching (Lim, 1996 ; Pandit and Prasad, 2003 ; Resurreccion et al., 2014 ; Xu and Shi, 2017 ).

To investigate the effect of microwave inactivation on processed food, experiments were performed with spicy sauce consisting of various foodstuffs such as potato, carrot, onion, garlic, and pepper. The total bacterial count was decreased to 3 log CFU/g after 3 min of microwave heating, compared to a level of 6 log CFU/g in the controls without treatment, while heat-resistant microorganisms were reduced by 2 log CFU/g (Fig.  3 ).

The results of this study indicate the improvement in sensory qualities obtained by using microwaves rather than conventional heating with steam or hot water. The organoleptic qualities of a sauce such as its taste, flavor, color, and texture were significantly ( p  < 0.05) better after microwave treatment than after conventional conduction heating. The scores for the organoleptic characteristics were higher by 0.2–0.4 points for microwave heating ( p  < 0.05). Especially, when microwave heating inactivated, the taste and flavor related to spicy characteristic of the sauce were excellent as around 4.0 points. Moreover, microwave inactivation has several advantages such as energy efficiency due to the shorter processing time.

Combination of microwave heating and retorting

The sterilization effect obtained by combining microwave heating as preheating followed by retorting was confirmed by a reduction in the total cell count of 10 6 CFU/g for unpeeled potatoes and spicy sauce (Table  1 ), and the heating sterilization time for the retorting phase was reduced by 50% (i.e., 10 min, versus 20 min for traditional retorting). The combination of microwave heating and mild retorting was expected to result in a higher food quality during complete sterilization compared to using conventional retorting at 121 °C, because heat-resistant bacteria appeared to be inactivated after applying the microwave pretreatment.

Table 1

Sterilization effects on potatoes and spicy sauce for the combination of microwave heating and retorting compared with other methods

Different superscript letters indicate values that differ significantly by ANOVA with Duncan’s multiple-range test at p  < 0.05

1 Data are mean ± standard-deviation values ( n  = 10)

The results obtained in this study suggest that microwave inactivation can be useful for improving the organoleptic qualities and microbial safety of various vegetable-based processed foods as a pretreatment process or in combination with retorting (Coronel et al., 2007 ; Malyshev et al., 2019 ). When the microwave heating is applied to vegetable foods, the temperature rise is faster than the hot water and steam heating in blanching, cooking and pasteurization, thus shortening the heating time which is advantageous in quality improvement and preservation of nutrients (Malyshev et al., 2019 ; Park et al., 2017 ).

Compliance with ethical standards

The authors declare that they have no conflict of interest.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Contributor Information

Won-Il Cho, Email: [email protected] .

Myong-Soo Chung, Email: rk.ca.ahwe@gnuhcsm .

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Ivory Soap in the Microwave

Updated: Sep 29, 2022 · This post may contain affiliate links.

What happens when you put Ivory soap in the microwave? Let's find out with this quick and easy one minute science experiment!

Microwaving Ivory Soap - Step by Step

What did we learn, expand the experiment, more stem activities for kids, microwaving ivory soap - a science experiment.

If you're looking for a really quick and easy science experiment to do with the kids, this is a great one to try. It's quick, simple, and great fun for the whole family.

And all you need is a microwave and a bar of Ivory soap - easy peasy!

This science experiment is:

• Easy to do in just one minute!
• Great fun for pre-school and elementary aged kids.
• A fun rainy day activity.

Step 1: Unwrap a bar of Ivory soap, and place it on a microwave safe dish. I suggest using a big plate to keep mess to a minimum.

Step 2: Put it in the microwave, and microwave on high for one minute. Watch through the window to see the show! You'll see the soap start expanding into a big, fluffy cloud.

Step 3: Remove the plate from the microwave. (Careful - it may be hot!) Spend some time examining the soap foam and making your observations. What does it feel like? Why do you think it transformed in this way?

Ivory Soap contains lots of air pockets, making it light and fluffy. This is also why Ivory soap floats if you drop it into water.

When the soap is heated in the microwave, water vapor escapes from the air pockets, making it fluff up! Pretty cool, huh?

Try microwaving other brands of soap as well. Do you get the same result? Different brands will contain different amounts of air pockets. Some will fluff up when heated and some will not. If they don't fluff up, what does happen to them?

Try dropping various brands of soap into a tub of water. Which ones sink and which ones float? What does that tell you about the amount if air inside? Which ones do you expect to fluff up when microwaved? Test your hypothesis!

Weigh the soap before microwaving and again afterwards. Does the weight change?

If you loved this quick science experiment, check out these other fun activities for kids:

• Best Science Activities for Kids
• STEM Activities for Elementary Kids
• Magic Milk Experiment

What happens when you microwave a bar of Ivory soap? Lets find out in this quick and easy, one minute science experiment!

• Bar of Ivory Soap
• Microwave Safe Plate

Instructions

• Unwrap a bar of Ivory soap, and place it on a large, microwave safe plate.
• Microwave on high for one minute. Watch through the window to see the soap transform into a fluffy cloud.
• Remove the plate from the microwave carefully and make your observations. Touch and feel the soap!

Use a large plate to minimize the mess in your microwave!

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Pin it to share or save for later!

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• Microwave Ice

Microwave Ice Science Experiment

This week's experiment is a result of defrosting some frozen food. Have you ever wondered why there is a defrost setting on your microwave? Why can't you just use the regular setting?

• a microwave oven

Fill one glass about half full of water. Fill the other about half full of ice cubes. Work quickly, as you don't want any of the ice to melt before you start. Put both into the microwave oven and cook both at full power for one minute. Carefully, because things may be very hot, remove both glasses from the oven. You will find that the water is quite hot, but the ice will not have melted at all. Why?

Your microwave oven works by directing microwave radiation at your food. Radiation! Is my food going to glow in the dark? No, here radiation means radiant energy, which includes visible light, radio signals, microwaves, and the rest of the electromagnetic spectrum.

As we have seen in the past, water molecules are polar. One end of the molecule has a positive charge, and the other end has a negative charge. The water molecules rotate to align with the alternating electric field produced by the microwaves. As they rotate quickly back and forth, the water gets hot.

On the surface of the frozen food, some of the ice will begin to melt at room temperature. The microwaves will cause this tiny bit of water to get hot. Then the oven's defrost setting turns the power off for a few seconds, giving that heat time to be absorbed into the surrounding food. That heat melts a bit more of the ice, so when the oven cycles back on, there will be more water available to heat. Then the oven cycles off again, and the heat is again absorbed by the surrounding ice.

If the oven did not cycle on and off, all the heat would be concentrated in the food near the liquid water. That part would burn before the rest of the food began to thaw.

The same is true for the other power settings of most microwave ovens. Setting the power at 50% does not turn down the amount off microwave radiation. Instead, the oven cycles on and off to give you about 50% of the heating that you would get if it were on continuously.

Have a wonder filled week!

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Microwave processing: Effects and impacts on food components

Affiliations.

• 1 a College of Food Science and Engineering , Northwest A&F University , Yangling , Shaanxi , China.
• 2 b College of Mechanical and Electronic Engineering , Northwest A&F University , Yangling , Shaanxi , China.
• 3 c Department of Biological Systems Engineering , Washington State University , Pullman , WA , USA.
• PMID: 28613917
• DOI: 10.1080/10408398.2017.1319322

As an efficient heating method, microwave processing has attracted attention both in academic research and industry. However, the mechanism of dielectric heating is quite distinct from that of the traditional conduction heating, and is widely applied as polar molecules and charged ions interaction with the alternative electromagnetic fields, resulting in fast and volumetric heating through their friction losses. Such a heating pattern would cause a certain change in microwave treatment, which is an unarguable reality. In this review, we made a retrospect of the essential knowledge about dielectric properties and summarized the concept of microwave heating, and the impact of microwave application on the main components of foods and agricultural products, which are classified as carbohydrates, lipids, proteins, chromatic/flavor substances, and vitamins. Finally, we offered a way to resolve the drawbacks of relevant microwave treatment and outlined the directions for future research.

Keywords: Foods; carbohydrates; chromatic/flavor substances; lipids; microwave; proteins; vitamins.

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Why You Shouldn’t Microwave Your Food in Plastic Containers, According to Toxicologists and an Epidemiologist

Glass containers are really where it's at.

Korin Miller has spent nearly two decades covering food, health, and nutrition for digital, print, and TV platforms. Her work has appeared in Women's Health, SELF, Prevention, The Washington Post, and more.

When it comes to heating up food, it’s generally recommended that you avoid microwaving stuff in plastic containers. But while many people are aware that this isn’t an ideal way to heat up food, many still do it. 

Even if you avoid microwaving plastics, it’s understandable to be fuzzy on details of why this isn’t ideal for food prep. So, why is it so bad to microwave plastics, and what can happen? Here’s the deal, according to toxicologists and an epidemiologist. 

Why is it so bad to microwave plastics, anyway?

There are a few things to consider here. “Microwaving in plastic heats up the dish as well as the food item,” says Phoebe Stapleton, Ph.D. , associate professor in the Department of Pharmacology and Toxicology at Rutgers University. “This increased temperature allows for the chemicals within the plastic dish to be released into the food being reheated.”

That’s even true of plastics that are marked “microwave safe,” says Kelly Johnson-Arbor, M.D ., a toxicologist at MedStar Health. (What the label really means is that it’s more a designation to indicate that your plastic container won’t easily break down when you nuke it a few times, she says.) “Despite the stable chemical structure of plastic products, however, chemicals can leach from plastics under certain conditions, including exposure to high temperatures such as those experienced during microwaving.”

Those chemicals include bisphenol-A (BPA) and phthalates, which can accumulate in the body’s tissues and are linked to negative health effects (more on those in a minute). “Microwaving can also enhance the release of tiny plastic particles called microplastics into foods and drinks,” Johnson-Arbor says. 

A 2023 study out of the University of Nebraska-Lincoln backs this all up:  For the study, researchers experimented on two baby food containers made from polypropylene and a reusable pouch made of polyethylene. The containers were filled with deionized water or 3% acetic acid, meant to mimic dairy products, fruits, and vegetables — commonly found in toddler and baby food — and then nuked them in the microwave. The researchers discovered that the amount of nanoparticles that ended up in the food and liquid varied but estimated that infants who drink products with microwaved water and toddlers who have microwaved dairy products take in the largest relative concentrations of microplastics. In a later experiment that tested those concentrations on kidney cells, the researchers found that just 23% of the exposed cells survived.

Beyond all that, this is less concerning, but still worth mentioning: While plastic gear is generally durable, regularly microwaving your containers increases the wear of the plastic, per Stapleton. 

Food & Wine / Getty Images

What, exactly, should you avoid?

Microwaving anything in plastic isn’t ideal, Stapleton says. But if you need to go this route, Johnson-Arbor suggests looking for products that are labeled “BPA-free.” 

“However, containers that are labeled as being BPA-free may still contain other potentially harmful bisphenol chemicals,” she says. “Just because a container is advertised as being BPA-free does not mean that it is entirely safe.” 

Stapleton agrees. “While the packaging may say ‘microwave-safe,’ this is not referring to human health,” she says. “No plastic is ‘OK.’”

“In general, individuals should avoid microwaving all plastic products, regardless of the exact type of plastic or plastics used to create them,” says Jordan Kuiper, Ph.D. epidemiologist and assistant professor in the George Washington University Milken Institute School of Public Health.

What can happen if you do microwave your food in plastic containers?

If you heat food in a plastic container once or twice, you’ll probably be just fine. But regularly doing this is definitely not great. “It may not be immediately detrimental, but continued use increases exposure and dosage to chemicals that have demonstrated risk for disease including cancers, endocrine disruption and fertility issues, and metabolic and neurological disease,” Stapleton says. 

Kuiper says that scientists are only beginning to understand the health effects nanoplastics can have on people. “Recent studies have found these plastic particles in human tissues that they certainly do not belong in, including the brain, heart, placenta, and testicles,” he says. Kuiper also cites a recently published study in the New England Journal of Medicine that found a 4.5 times higher risk of heart attack, stroke, or death in people who had nanoplastics detected in their cardiovascular system. 

“For chemicals used as plasticizers during the production of plastic products, they tend to be classified as endocrine-disrupting chemicals, those chemicals which are capable of interfering with hormones in the human body,” Kuiper says. 

Ultimately, experts say you really shouldn't be nuking your plastic containers. “Immediately stop microwaving plastics,” Kuiper says. “When feasible, it is also highly recommended that products made from glass, which are microwavable, be used as a substitute. 

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• Diet & Nutrition

What If Ultra-Processed Foods Aren’t as Bad as You Think?

J essica Wilson is passionate about the pupusas from Costco. Not just because they’re tasty, but also because they’ve helped the California-based registered dietitian fight back against the mounting war on ultra-processed foods .

It all started in the summer of 2023, when author and infectious-disease physician Dr. Chris van Tulleken was promoting his book, Ultra-Processed People. While writing it, van Tulleken spent a month eating mostly foods like chips, soda, bagged bread, frozen food, and cereal. “What happened to me is exactly what the research says would happen to everyone,” van Tulleken says: he felt worse, he gained weight, his hormone levels went crazy, and before-and-after MRI scans showed signs of changes in his brain. As van Tulleken saw it, the experiment highlighted the “terrible emergency” of society’s love affair with ultra-processed foods.

Wilson, who specializes in working with clients from marginalized groups, was irked. She felt that van Tulleken’s experiment was over-sensationalized and that the news coverage of it shamed people who regularly eat processed foods—in other words, the vast majority of Americans , particularly the millions who are food insecure or have limited access to fresh food; they also tend to be lower income and people of color. Wilson felt the buzz ignored this “food apartheid,” as well as the massive diversity of foods that can be considered ultra-processed: a category that includes everything from vegan meat replacements and nondairy milks to potato chips and candy. “How can this entire category of foods be something we’re supposed to avoid?” Wilson wondered.

So she did her own experiment. Like van Tulleken, Wilson for a month got 80% of her daily calories from highly processed foods, not much more than the average American . She swapped her morning eggs for soy chorizo and replaced her thrown-together lunches—sometimes as simple as beans with avocado and hot sauce—with Trader Joe’s ready-to-eat tamales. She snacked on cashew-milk yogurt with jam. For dinner she’d have one of her beloved Costco pupusas, or maybe chicken sausage with veggies and Tater-Tots. She wasn’t subsisting on Fritos, but these were also decidedly not whole foods.

Read More : Why Your Diet Needs More Fermented Pickles

A weird thing happened. Wilson found that she had more energy and less anxiety. She didn’t need as much coffee to get through the day and felt more motivated. She felt better eating an ultra-processed diet than she had before, a change she attributes to taking in more calories by eating full meals, instead of haphazard combinations of whole-food ingredients.

How could two people eating the same type of foods have such different experiences? And could it be true that not all ultra-processed foods deserve their bad reputation?

These hotly debated questions come at a crucial moment. In 2025, the U.S. government will release an updated version of the Dietary Guidelines for Americans, which tell people what they should eat and policymakers how to shape things like school lunches and SNAP education programs. The new edition may include, for the first time, guidance on ultra-processed foods. Officials at the U.S. Food and Drug Administration are also reportedly weighing new regulatory approaches for these products.

The food industry, predictably, maintains that ultra-processed foods have been unfairly demonized and can be part of a healthy diet. Likely sensing a threat to their bottom line, large food companies have reportedly already started lobbying against recommendations around processed-food consumption.

What’s more surprising is that even one dietitian would take their side, defending a group of foods that, according to 2024 research , has been linked to dozens of poor health outcomes ranging from depression and diabetes to cancer, cardiovascular disease, and cognitive impairment . Wilson has endured plenty of criticism for her position, which is not popular among the nutrition-science establishment. But she stands by it. Sweeping recommendations to avoid all ultra-processed foods stand to confuse people and make them feel bad about their diets, Wilson says—with questionable upside for their health.

What is a processed food, anyway? It’s a rather new concept. Foods are mainly judged by how many vitamins, minerals, and macronutrients (think fat, protein, and carbs) they contain, as well as their sugar, salt, and saturated-fat contents. There’s no level of processing on a food label.

Scientists don’t agree on exactly how to define processed foods. If you give two experts the same ingredient list, “they will have different opinions about whether something is processed or not,” says Giulia Menichetti, a principal investigator at Harvard Medical School who researches food chemistry. Take milk. Some experts consider it a processed food because it goes through pasteurization to kill pathogens . Others don’t think it belongs in that category because plain milk typically contains few additives beyond vitamins.

The most widely used food-classification system, known as NOVA , uses the latter interpretation. It defines an unprocessed food as one that comes directly from a plant or animal, like a fresh-picked apple. A minimally processed food may have undergone a procedure like cleaning, freezing, or drying, but hasn’t been much altered from its original form. Examples include eggs, whole grains, some frozen produce, and milk.

Read More : What's So Great About Cottage Cheese?

Under NOVA, a processed food contains added ingredients to make it taste better or last longer, such as many canned products, cured meats, and cheeses. An ultra-processed food, meanwhile, is made largely or entirely from oils, sugars, starches, and ingredients you wouldn’t buy yourself at the grocery store—things like hydrogenated fats, emulsifiers, flavor enhancers, and other additives. Everything from packaged cookies to flavored yogurt to baby formula fits that description.

“You end up with a system where gummy bears and canned kidney beans” aren’t treated so differently, says Julie Hess, a research nutritionist with the USDA. At the end of the day, they’re both processed.

Why should that matter to anyone aside from researchers and dietitians? Because most people who care about their health have the same question about processed foods: Are they killing me? And right now—despite their looming possible inclusion in dietary guidelines—no one really knows the answer. There’s limited cause-and-effect research on how processed foods affect health, and scientists and policymakers have yet to come up with a good way to, as Hess says, “meaningfully delineate between nutrient-dense foods and nutrient-poor options”—to separate the kidney beans from the gummy bears.

Hess and her colleagues drove home that point in a 2023 study , for which they created a hypothetical diet almost entirely made up of ultra-processed foods like breakfast burritos, canned soup, and instant oatmeal. The diet wasn’t nutritionally stellar—it was high in sodium and low in whole grains—but scored an 86 out of 100 on a measure of adherence to the federal dietary guidelines, considerably better than the average American’s score of 59. The experiment highlighted that there are nutritious ultra-processed foods, and that certain ones “may make it easier and more convenient to have a healthy diet, because a lot of these foods are more shelf-stable, they’re more cost-effective, they’re sometimes easier to access,” Hess says.

A 2024 study backs up the idea that people who eat processed foods can still be healthy. Although the researchers did find links between heavily processed diets and risk of premature death, they concluded that overall diet quality may be more important than how many processed foods someone eats. In other words, if someone is eating plenty of nutritious foods, maybe it’s OK if some come from a wrapper. The study aimed to correct “the potential misperception that all ultra-processed food products should be universally restricted and to avoid oversimplification when formulating dietary recommendations,” the authors wrote.

Even vocal critics of ultra-processed foods, like van Tulleken, agree that not all are equal. He’s particularly concerned about those that are high in salt, sugar, or saturated fat, which is true of many ultra-processed foods but not all of them. These elements have long been nemeses of the nutrition world, but van Tulleken argues they’re especially damaging when eaten in industrially made foods spiked with additives and designed to be as appetizing as possible . “We’ve had fat, salt, and sugar in abundance in our diet for a century, and I'm the first to say they are the nutrients of concern,” van Tulleken says. “But they weren’t a concern when we were mixing them up at home, because when you cook at home, your purpose is not to get me to eat 3,000 calories in half an hour.”

Read More : 6 Health Myths About Oils

Industrial production means that ingredients undergo complex chemical changes, the implications of which researchers don’t fully understand, says Menichetti, the food chemist. “We co-evolved with our food, so if our bodies got used to certain chemicals in certain ranges,” altering foods’ compositions via processing could change the way they affect human health, she says.

Already, some studies suggest that ultra-processed foods affect the body differently than unprocessed ones, regardless of their nutrient profiles. One 2024 study found that plant-based foods, which are traditionally considered healthy , lose many of their benefits and even contribute to higher risks of heart disease and death when they’re ultra-processed (when a whole grain turns into store-bought bread, for example). And a 2020 review article found numerous bad outcomes—cancer, cardiovascular disease, IBS , depression, and more—linked to ultra-processed diets and not a single study connecting them to better health. Those results suggest that a food’s processing level is linked to its “healthiness,” the authors wrote.

A 2019 study from the National Institutes of Health (NIH) provides some of the strongest evidence that ultra-processed foods can directly cause health problems. For the study, 20 U.S. adults lived in an NIH laboratory for a month. For two weeks, they ate minimally processed foods like vegetables and nuts. For the other two, they ate ultra-processed foods like bagels and canned pasta.

The two diets were designed to be equivalent in calories, sugar, salt, and macronutrients, but people could eat as much or as little as they wanted at mealtimes. On the ultra-processed diet, people ate more and gained weight. Meanwhile, on the minimally processed one, they lost weight, had positive hormonal changes, and saw markers of inflammation drop. Those findings suggest something about ultra-processed foods drives people to overeat and may cause health problems, says lead author Kevin Hall—but it’s not yet clear what that something may be.

“There’s a very, very long list of potential candidates,” Hall says. Is it the combination of ingredients manufacturers use to make foods tasty? Is there a problematic ingredient or additive? Does something about the manufacturing process degrade the food’s quality? Or is the explanation something else entirely?

In November, the 2025 Dietary Guidelines Advisory Committee is expected to release a report on ultra-processed foods, which will assess the available data on how they affect the body. More research is needed. But at a meeting in May, committee member Dr. Fatima Cody Stanford, an obesity-medicine specialist at Massachusetts General Hospital, previewed the group’s findings: that people who eat highly processed diets are at risk of obesity.

Even with questions outstanding, we already know that some ultra-processed foods are harmful, says Kendra Chow, a registered dietitian and policy and public affairs manager at the nonprofit World Cancer Research Fund International. Stereotypical “junk foods” that are high in salt, sugar, or saturated fat—things like chips, candy, and hot dogs—have long been linked to health problems like cancer and heart disease. The science on those foods is clear enough that people should limit how often they eat them, she says.

What’s trickier, Chow says, is figuring out what to do about foods that are ultra-processed but seem to have more nutritional value, like flavored yogurts and store-bought vegetable pasta sauces. “Stigmatizing a broad category of foods that also includes lower-cost, accessible options, especially without providing an alternative or improving access and affordability of healthy foods,” is not the answer, she says.

Read More : Can Food Really Change Your Hormones

Despite his prominent campaign against ultra-processed foods, van Tulleken agrees. He realizes a ban on them wouldn’t be practical; it would essentially wipe out the modern food system, with particularly disastrous consequences for people of lower socio-economic status. (He would, however, like to see more regulation of food marketing and warning labels on processed products high in salt, sugar, or saturated fat.) Though he feels strongly that ultra-processed foods are contributing to a modern public-health crisis, van Tulleken also recognizes that they serve an imperfect purpose in a world where many people are strapped for time and money.

Even Hall, the NIH researcher, eats ultra-processed foods—and not infrequently. Most days for lunch, he heats up a frozen meal in the microwave. “I’ll try to choose one that is high in fiber and whole grains and legumes and low in sodium and saturated fat and sugar,” he says. But he knows that technically, it’s in the same category as a Twinkie.

After her experiment last summer, Wilson also continues to eat plenty of processed foods—and to feel good about it. To her, the debate is about more than food; it’s also about the realities of living in a country where grocery prices are spiking and lots of people simply don’t have the resources to eat three home-cooked meals made from fresh ingredients every single day.

“People often assume that a dietitian’s day is telling people to eat less,” Wilson says. But she says she spends far more time helping people figure out how to eat more—whether because they’re trying to feed a family on a tight budget or because they simply don’t have time and energy to cook—and how to add nutrient-rich foods to their diets in a way that’s affordable. For some of those people, ultra-processed foods may be the difference between going to bed hungry or full, Wilson says. She’d pick full every time.

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Write to Jamie Ducharme at [email protected]

Why You Should Think Twice Before Defrosting Food In The Microwave

How many times has a microwave come to the rescue when you've forgotten to take out frozen meat and thaw it in the refrigerator hours before cooking? The handy appliance can defrost food in a matter of minutes, making it seem like a  microwave cooking hack that you'll wish you knew sooner  – but while the USDA considers microwaves to be a safe way to thaw food, and some models even come with specific defrost settings, not all is as easy as it seems. Defrosting food in this appliance can be trickier than expected, which is why you might want to think twice the next time you do so.

For starters, microwaves are notorious for heating food unevenly, and that applies to defrosting too. There are several reasons why this might happen. One possible explanation is that some elements inside your food have a lower water content, which causes them to absorb more heat and defrost faster than others. The way the food is arranged on a plate can play a role too, as can the settings of the microwave. Sometimes, the culprit could even be a faulty appliance. 

Regardless of the cause, unevenly-defrosted food can be a safety concern, and you might find that your food has thawed perfectly from the outside, but is still rock-hard frozen in the middle. The unsafe aspect has to do with the so-called "Danger Zone."

Microwaves can raise the temp of frozen food to unsafe levels

The  USDA classifies temperatures between 40 and 140 degrees Fahrenheit as the Danger Zone for food, in which bacteria such as salmonella and E. coli can swiftly multiply, reaching dangerous levels after two hours. Refrigerators defrost foods whilst keeping them at a cool and constant temperature of 40 degrees Fahrenheit or lower, which is why they are one of the safest and best ways to thaw food, especially frozen meat .

Meanwhile, a microwave warms frozen items enough for their temperature to reach higher than 40 degrees Fahrenheit, but without fully cooking them to destroy harmful bacteria. This means that your items end up partially cooking to a temperature that falls squarely in the Danger Zone. It's also why thawing in hot water or at room temperature is a huge no-no, as both of these methods will leave your foods at unsafe temperatures.

Although microwaves at a defrost setting normally function at 20% to 30% of their usual power to prevent the food from cooking, their tendency for uneven heating does not help. Some parts of your food may reach temperatures between 40 to 140 degrees Fahrenheit, while others still look like they could do with a few more minutes. To be safe, only defrost ingredients in the microwave if you plan to cook them immediately. If not, refrigerators are a much safer option, as they can keep thawed foods fresh for a couple of days before you cook them.

How to safely defrost food in the microwave

There are certain safety tips that will ensure a better defrost if you absolutely must use the microwave. For one, always spread out the frozen items evenly and lay them flat on a microwave-safe plate or bowl. Piling items will only make the thawing more inconsistent. Always flip solids and stir liquids about halfway through the process, whilst also rotating the container and breaking up any large lumps. All of this will help distribute that heat more uniformly through the food.

Fruits and vegetables only take two to three minutes to thaw, whereas frozen liquids can take a couple more. Meat requires a little more calculation. While the exact time will vary depending on the wattage of your appliance, a 1,000-watt microwave takes eight to 10 minutes to defrost each pound of meat. Add those minutes based on how many pounds of food you're thawing, and set the timer accordingly.

That said, consider defrosting less than two pounds of meat in one go when using a microwave. Any more, and the meat will have a harder time thawing properly, leaving you with frozen centers and cooked outer layers. It's also wise to avoid tender proteins like fish or small veggies like peas: These go from frozen to cooked in a microwave, completely skipping past the thawed stage. Consider dousing them in some cold water instead, or just cooking them directly (you can even cook frozen chicken without thawing  it first).

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Science News

More than 100 bacteria species can flourish in microwave ovens.

The microbes turned up in swabs of 30 microwave ovens in different settings

Microwave ovens can harbor thriving bacterial communities that have somehow adapted to the harsh environment, a new study reports.

GK Hart/Vicky Hart/Stone/Getty Images Plus

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By Abdullahi Tsanni

August 23, 2024 at 11:00 am

Even the microwave oven in your kitchen is not immune to bacteria.

The irradiating environment within a microwave oven might seem inhospitable to microbes. But swabs from microwave ovens in several different locales identified over 100 bacterial strains , researchers report August 7 in Frontiers in Microbiology. This is the first time that scientists have documented microbial communities living in microwave ovens, according to the researchers.

Microbiologist Manuel Porcar and colleagues swabbed the insides — including the walls and rotating platter — of 30 microwave ovens that were being actively used in three different settings: 10 from kitchens, 10 from labs and 10 from other shared spaces such as cafeterias. The swabbed samples were then transferred to lab dishes, all of which led to significant bacterial growth.

DNA analysis of the bacterial colonies showed they were dominated by Proteobacteria , Firmicutes , Actinobacteria and Bacteroidetes , all of which are commonly found on human skin and surfaces that people frequently touch. The cultures from kitchen microwave ovens included bacteria that can cause food-borne disease, including Klebsiella and Brevundimonas . It’s unclear how these bacterial strains could survive in microwave ovens, the team says, and further work is needed to understand how they’ve adapted to high temperatures and electromagnetic radiation.

Porcar, of the University of Valencia in Spain, notes that the microorganisms they found in domestic microwave ovens were the same as those that can be found on a kitchen surface ( SN: 3/1/22 ). “Some of them are pathogenic, and one must clean the microwave as much as any other kitchen surface,” he says. However, he stresses that kitchen microwave ovens aren’t a particular cause for concern. “Nothing to be more worried about than the cleaning of any other part of a kitchen in contact with food.”

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Lunch thefts and dirty dishes: How to navigate breakroom melodramas

The following column was originally published Aug. 23, 2023.

If your office’s breakroom is a hotbed of unresolved conflict, you’ll recognize these characters and their dramas.

At 3 p.m., “Harry” exploded into the executive director’s office because someone swiped his turkey and cheese sandwich. According to Harry, one bite would have convinced anyone mistaking his sandwich for theirs that they’d made a mistake because he used Jarlsberg cheese and fresh tomatoes. Harry’s now walking through the workplace checking everyone’s trashcans and desk drawers for “evidence.” He vows that if no one confesses, he’ll declare open season on everyone’s food. Predictably, the ED sends out an office-wide email requesting employees respect others’ food.

The engineering firm in Midtown installed two large Keurig coffeemakers so no one had to wrestle coffee grounds in the morning. Unfortunately, “George” mainlines coffee and fails to notice the “add water” light. Or perhaps he does, because he’s known for filling several large cups at a time, leaving both machines with blinking “add water” lights after he returns to his desk.

And, apparently, no one at a downtown Anchorage advertising firm knows how to clean up their messes. Periodically, the front-desk staff leaves large notes on the fridge and cupboard doors reminding everyone “it’s not that much bother to rinse your dishes and put them in the dishwasher!” When the ad agency manager comes though, she strips the notes and sends out an email reminding everyone that account executives occasionally take clients into the breakroom and clients don’t need to see either the messes or the notes. According to the front desk staff, it’s the agency manager who most often leaves her unwashed cups in the sink.

Then there’s “Rachel.” She prefers talking on speakerphone when in the breakroom. As a result, anyone getting a cup of coffee or microwave learns more than they want to about her pesky medical issues and husband’s annoying habits. When a coworker respectfully suggested Rachel carry on those conversations in the restroom, Rachel responded in horror: “And have him hear the flushing toilet?”

If you’ve wondered why the breakroom, intended as a place where employees can connect and refuel, instead becomes a breeding ground for festering conflicts, the answer is simple. The common solutions, such as the “don’t swipe others’ sodas” emails, don’t work. The posted signs help the front desk or office manager blow off steam, but the only sign that commands attention is “Undated or expired food will be tossed on Friday.” Everyone rescues their fresh food, or grumbles later, but leaves their science experiments to their fate. Hungry food thieves don’t respect labeled names on food, but simply look around to ensure they can sneak the food away without detection. Two microwaves ease the problem caused by microwave hogs but result in two microwaves needing cleaning.

The engineering firm, however, fixed their breakroom problem — by accident. They invited me to provide a communication skills seminar because their client survey revealed clients considered the engineers lacking in conflict skills. Knowing the engineers would consider the training a deadly waste of time, I sent out an advance email. The email, titled “Send me your fridge food thief stories,” asked for breakroom conflicts so everyone could practice their skills on real issues. That’s when I leaned about George and others. Actual problems flooded my inbox. When I distributed the session’s handouts, the attendees turned to the packet’s last pages and started laughing.

When we started the skills practice, George learned he hadn’t traveled under the radar with his “I never see the add water light” coffeemaker protest. Everyone vied to be the one who confronted George, and his ears stayed red through the remainder of the session. Similarly, others discovered their high rank on the “suspect list” for leaving dishes in the sink or stealing sodas or yogurts.

As you might suspect, while the training provided useful conflict skills, the more important outcome was an end to the breakroom sagas. The breakroom culprits discovered others knew exactly who left dishes in the sink, messes in the microwave, sneaked off with others’ sandwiches, or overshared during speakerphone conversations.

Would you like to try this at your workplace? Ask for a few true stories and see what turns up — or perhaps it’s safer to simply leave this article on the breakroom wall.

Lynne Curry | Alaska Workplace

Lynne Curry writes a weekly column on workplace issues. She is author of “Navigating Conflict,” “Managing for Accountability,” “Beating the Workplace Bully" and “Solutions,” and workplacecoachblog.com. Submit questions at workplacecoachblog.com/ask-a-coach/ or follow her on workplacecoachblog.com, lynnecurryauthor.com or @lynnecurry10 on X/Twitter.