CAUTION!! Be careful with this!! This experiment uses a knife AND a microwave, so you’re playing with things that slice and gets things hot. If you’re not careful you could cut yourself or burn yourself. Please use care!
We’re going to create the fourth state of matter in your microwave using food. Note – this is NOT the kind of plasma doctors talk about that’s associated with blood. These are two entirely different things that just happen to have the same name. It’s like the word ‘trunk’, which could be either the storage compartment of a car or an elephant’s nose. Make sense?
Plasma is what happens when you add enough energy (often in the form of raising the temperature) to a gas so that the electrons break free and start zinging around on their own. Since electrons have a negative charge, having a bunch of free-riding electrons causes the gas to become electrically charged. This gives some cool properties to the gas. Anytime you have charged particles (like naked electrons) off on their own, they are referred to by scientists as ions. Hopefully this makes the dry textbook definition make more sense now (“Plasma is an ionized gas.”)
So here’s what you need:
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If you read over the comments from other students, you’ll find out that they like a lot of different fruits… 🙂
Would it work with something other than a grape?
We tried purple grapes, and it worked fantastically! We did leave them in the microwave a bit too long, and they smoked and smelled.
You’re right – there are a lot of explanations out there, and it’s hard to know which one is accurate. Plasma is one of the states of matter that exists in a flame (albeit a small amount) and also with electric arcs. In this experiment, can you detect either one? If you can, plasma is present in the experiment.
Thank You! We had a great time with this! At first it didn’t seem to be working so we used half a grape because they were so big. It still didn’t work, but then my son didn’t open it up a much as I did, and it worked! I would say it worked about half the times we tried, and when it worked, it was very obvious. We tried a cutie slice, but I think it was too juicy. We also tried a marinated cherry, and it did not work either. Our microwave is just a little, old, extra one we keep around. 900 Watts. My kids are almost 8 and 10, and we discussed Atoms, Protons, Neutrons, Electrons, and Ions, as well as the states of matter.
When looking around the web, some people seem to think that it is a myth that plasma is involved in this experiment. Is there any scientific documentation that we could look up? I don’t know where to start.
Possibly. Did you try a grape tomato? What happens if you visit a friend’s house and give it a try?
We just tried the grape plasma experiment and it didn’t work. Hmmm… we tried it several times. We tried different size grapes and made sure the skin was still attached when opened. We have done this before and it did great. The only variable we can think of that has changed is we have a new LG microwave. I’m wondering if that has anything to do with it. What do you think?
We just did it with a blueberry too. It worked and was very cool!!
Try both!
small grape or big grape?
(:
Cherry tomato?
Do you have to use a grape or can you use something else?
Awesome! Great job keeping at it!
After your suggestion of wetting and putting in freezer for a minute, It worked! Also, I noticed that you can’t cut into equal sections. One side has to be cut smaller. Thanks for your advise.
It’s totally normal to feel disappointed… but don’t let that stop you. 🙂 Get curious and see if you can figure out a way to make it work. Here’s a couple of suggestions: get the grape wet first, cool it down for a few minutes in the freezer first, change the height by placing it on an inverted glass in a the microwave, and going to a friend’s house and trying their microwave. You can also try some of the other suggestions posted by students (there’s a lot of them here).
Don’t forget that the people that LEARN the most are the ones that fall down the most when they’re first learning how to ski (or do science…). Keep up the good work and get curious about what’s going on! 🙂
Disappointed. I have tried 5 green seedless grapes and none of them worked. After the first three, I turned off the turntable. Still only bubbled. On the last one I even put on for 30 seconds and still no fire or anything. I’m not sure what I’m doing wrong. The halves are still attached by the skin. My microwave if only two years old.
more like electricity grape my hair no my neck stood up when it made this sound TZZZZZZZZZZZZZZZZZZZZZZZZZZZTZZZZZZZZZZZZZZZZZZZTZZZZZZZZZZZZZZZZZZZZZZZZZZZZ Z TZ TZ TZ ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ…………………BOOM!!!!!!!!!!! and it made the lights flicker SO COOL!!!!!!!!!!!
Read over the comments (there’s a lot) and see if it makes sense! 🙂 Part of science is having enough curiosity to figure it out on your own also!
how does it work
It’s a great experiment to spark curiosity, isn’t it? 🙂 There’s a lot I’ve written in the comment section… skim over it and see if any of it makes sense! 🙂
I still don’t know how it works. is it the acid that reacts to the hot gas in the microwave
So fun! Try eating the grape after it has popped I think that is okay I did it also look at slime recipes
We tried a lemon, and it didn’t make plasma. Instead, it slowly evaporated into bubbly lemon juice! Grapes, tomatoes, and olives all worked great, though! 🙂
No a lava lamp uses density changes to move blobs of liquid around like this one. Plasma is a high-energy cloud of electrified gas. Two totally different things!
would this be the same as a lava lamp?
My son wants to know:
Is fire plasma? If not, what is it?
Where does the electron go when it “pops” out of existence (from the Density exercise sheet)?
Usually the grape is hot when you take it out.. so be careful! The grape does get singed a bit at the edges, if you leave it in for a few seconds after the light show.
I have a question, when we zapped the grape, the plasma itself was hot, but when the grape came out of the microwave it was still cool to the touch (don’t worry we were careful). Why was the grape not burned?
My son figured out that the more citric acid in a fruit, the better the experiment worked. He realliy liked the way oranges and lemons reacted to the microwave.
I have done this it was great 🙂
I haven’t tried it… let me know how it goes! (I’ve tried cherry tomatoes, though…)
Will this work with cherries?
Zachary
Did you try changing the height of the grape and tomatoes, or just the horizontal position? And it may not work with all microwaves… have you tried a different one (like at a friend’s house?) Make sure you leave that thin bridge of skin attaching the two halves or it won’t work!
Hello we have done 8 trials using 6 grapes and 2 cherry tomatoes and did not work. We tried without rotation and for 30 seconds only got smoke.But we had FUN!!!!! Any advice?
Try cherry tomatoes!
Will it work if we use other fruits or vegetables? 🙁
tried this experiment. Super cool. 🙂 🙂
We tried to do it a couple of times with the grapes rotating and nothing happened (other than a bit of smoke) but after we set them to stay still in microwave it worked perfectly! ^_^ Also, did anyone else think that the aftermath of it all smelled like roasted marshmallows? O.o lol
Read over the comments and see if you can figure it out! 🙂 And ask questions of course… but first see if you can puzzle it out.
how does it do that
You’re right – it’s something really neat, and you’re very close! Did you read over the comments (I know there are a lot) for this experiment? A lot of kids have asked all kinds of questions about this one. Here’s the basic idea: Plasma is what happens to a gas when you add enough energy so that the molecules inside get so excited that they smack into each other with enough energy to knock electrons off the atoms. When this happens, you have free electrons zooming around in the gas, which gives the gas special properties, like being electrified. The plasma is made in your microwave by the grape’s juice (which is mostly water) and the power from the microwave. The energy from the microwave turns the liquid water (in t he juice) to a vapor (gas) and then into plasma just for a moment, which is the moment you see the fireball. Does that help?
I am trying to fully understand what’s happening. As soon as I mentioned plasma my oldest son (10) told me all about Wonder Woman and how she was formed from clay and plasma. I can’t fully explain what’s happening in a way my boys understand (doing this with a 10 and 9 year old). I think I sort of get it from what you said about grapes juice conducting electricity. It seems like you have to have something that conducts electricity in order to form/make/get plasma.
In trying to explain plasma and why the grape had a flame, I finally sort of gave up and asked the boys–what do you think it is? Because whenever I tried reading the explanation on here their eyes glaze over. The skin, the juice, or what? Why does the grape have get a flame? That led to an experiment–we tried a plum because the skin is similar to a grape and a lemon because its juicy. Neither one made a flame like the grape.
Are there other experiments you have with plasma? Or maybe different ways to explain it? I think I might be close to getting it but my boys aren’t. I feel like we are just tantalizingly close to learning something neat.
this looks cool
HOT!!!
what does plasma feel like?
Do you mean the grape? Only as long as the gas is ionized.
We didn’t have any grapes but after reading other comments, we plucked a couple of almost ripe cherry tomatoes from the garden. The first one bubbled and failed, but when we took out the rotating plate as suggested, we got a bunch of awesome zaps! It helped get rid of the smell of Ivory soap.
If you use an old microwave will it catch on fire?
WOW SCIENCE IS EPIC!!!!!!!!!!!!!!!!!!!!
Mia G. age 8
That should work just fine… be sure to look at the comments from other students so wee how they have handled using different microwaves.
Does it matter the wattage of the microwave. I have a 1200…
Thank you… showed my husband… and he loved it. He knew all about but still fun to show him something he knows about in his head. My 6 loved it too… but didn’t understand… we still did journaling with pictures and I did some notations for her for when she is older and wants to try again.
This was a big hit for the whole family. Now that our microwave smells like fire, I think we’ll stop. No grapes on hand but we did have tiny tomatoes. It was important to get just the skin, the juicier the better. 9th grader experimented with the rotten ones, and they sparked highest and with flame. The mold would sort of catch on a quick fire. I sliced some lemons to nuke to clean the microwave and oldest son poured some lemon juice on the tomato and got excite – Acid! Oh ya, big flame. I think mostly because of so much liquid? Anyways, my nose tells me that we have pushed the limits of our microwave. They enjoyed reading the text too. I tried to get a new microwave out of it, but we need summer shoes and a board shorts right now.
My daughter loved this experiment. She has wanted a plasma light for her room for some time and now understands a little more about it.
We did green seedless grapes – several – and had luck with all of them with various plasma shows.
She learned that a plate was good to use.
She learned that a paper towel was not a good idea as it burned. 😉
Did her first journal entry with this experiment and really enjoyed that as well.
Thanks.
This experiment is more about the states of matter than the actual atoms themselves, as it shows what happens when you excite the water molecule (hydrogen and oxygen) in its gaseous state to a point where it turns into plasma (that’s when you get the fireball in your microwave). Does that help?
We tried 9 grapes, all red and had success on 6! We discovered that using a clean dry surface go the best results. It seemed that dried or wet grape juice or water drops left on the plate from previous attempts affected the outcome negatively. My son then wanted to try more cuts with hopes of creating a larger glow, didn’t work. So he wanted to try the opposite, that didn’t work. We came to ask why but found the answer already here! 🙂
He did have another question about what this experiment tells us about atoms?
Thanks!
Colleen and Julian(8)
Light waves can be measured relative to some fixed point that emits light, and this light will go out from that source according to this inverse square law. So an object twice as far away from the source of light as another object will only receive 1/4 of the light energy, according to this law. This is quite handy in measuring distances in space.
What is the inverse square law
Oh no! I’ve never heard of a light and sound show… Did you read through the comments (I know there are a lot with this one) to see what other families have experienced?
it works with a baby tomatoe better
Uh oh…it seems we did break our microwave; now whenever we try to microwave something, it does a big light & sound show. Any way to fix this? Did we kill it? It’s kind of old, but never had problems before…
AWESOME! Purple grapes didn’t work for us either – but we used a small Concord with seeds, so maybe that’s why? Also, it was rotating. When we removed the rotator plate and used a “grape tomato,” we got a very big blast! We’re wondering how many times we can do this before we destroy our microwave…? My son wants to do it a bunch of times!
Great question! Did you read over the comments for this experiment? I know there are a lot of them… a lot of kids had the same question. This experiment won’t work with a single grape half… you need two grapes side by side that basically form an antenna. The concentrated electromagnetic field inside the grapes (generated by the microwave) quickly heats the grapes to a high temperature. As the grapes are heated each grape emits a jet of steam toward the other grape and the concentrated fields from each grape exceeds 3000 volts, which energizes the steam into plasma (an electrified gas), which forms a short circuit between the grapes and creates arching in the steam. When the grapes have used up their steam pressure, the plasma and the arc goes out.
You can read more on it here.
Happy experimenting,
Aurora
My son and I did the plasma grape experiment. It was cool. I understand what plasma is. What part of the grape is turning into plasma?
Thank-you!
Katrina
Before the flash occurs, current passes through the connecting piece of skin between the two grape halves. The flash happens when the connecting skin has dried out but the two halves still have enough water and energy in them to create a plasma in the air above them to carry current between them. So the connecting skin is a key part of the experiment. However, I’ve read that it is also possible to create a plasma between two whole grapes by placing them very close together with their stem holes facing each other. So in that case there is no skin connection, just the fact that the two grapes have enough energy in them to create the plasma between them to carry current from one to the other.
The key to this experiment is that grapes are small and juicy (i.e. wet inside). Microwave ovens generate energy in the form of microwaves – surprise! – that penetrate through food to heat the water molecules inside. When there is very little moist food in the oven to excite, for instance a grape or other small juicy fruit, all of the energy is focused in that one grape and can build up the electric field in the area of the grape. When the two halves of the grape are separated by a thin piece of skin, the electric field from the microwave creates an electric current that moves between the two halves through that skin. This concentrated current will quickly dry out the connecting skin, at which point it can no longer conduct electricity. Current still wants to pass between the two halves, and they are so close to each other and so much energy is concentrated in them that they actually heat the air between them until it’s a plasma. Since the plasma is electrically charged, it can conduct electricity between the two halves. This current passing through the plasma, a.k.a. an electric arc, is the big flash you see above the grape.
A good brief description of how plasma is created in this experiment (with pictures) can be found here:
http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/grape-plasmas/
Toward the bottom of the page read the sections titled “What is going on?” and “What is a spark?” Other good sources of information on creating plasma with a grape in a microwave:
http://van.physics.illinois.edu/qa/listing.php?id=818
http://www.madsci.org/posts/archives/dec97/882909591.Ph.r.html
is the skin that holds the grape together is what makes the plasma?
Why is it that thiplasma happens in these fruits? Do you think it would work with another type of fruit? I used a grape tomato (we were out of grapes 🙂 ) and the first time it was really big. The second time we did it, it was smaller, and shorter. Why do you think that is?
~Charleen’s daughter~
Plasma is a very hot gas, which will melt your container. A fluorescent tube (when lit) has plasma inside it. 🙂
My 7yo would like to “catch” the plasma. We put our grape halves in a zip lock bag, but all we caught was steam. How would one go about catching plasma? (Obviously we can’t do it with a grape in the microwave)
The boys loved this experiment! We have a turn table in our microwave and we didn’t get the reaction we were looking for until we placed the grape in the back of the microwave where it didn’t rotate.
Great questions! I only have answers for some, so you’ll have to help me figure out answers to all of them. 🙂 Unfortunately, to my knowledge, there’s no conclusive scientific study on the nutritional effects of microwaved food (none that have been verified). The microwave uses high-energy radio waves to excite the water molecules in your food by adding energy. If you leave food in too long, the water evaporates and ‘dehydrates’ the food, leaving it gummy and mushy (there’s still water vapor in the air inside the microwave, or it would dry out completely).
There’s a cool experiment about veggies and color here:
https://www.sciencelearningspace2.com/2011/08/the-science-of-broccoli/
Certain plastics will ‘leech’ chemicals into your food when exposed to microwave radiation. That’s why using pyrex glass in the microwave is safest. You can learn more about those here: http://www.cookingforengineers.com/article/99/Microwave-Safe-Containers
Microwaves are a fairly low frequency of radiation and that means their affect on the body, if any, would be less dangerous than higher frequency forms of radiation. Still, many people argue that radiation from standing in front of the microwave oven can affect us even though microwave doors are designed to keep in the radiation. Microwaves could leak out from the spaces in the oven near the door. It’s very important to keep the microwave oven clean as dirty microwave ovens are more likely to leak microwaves than clean ones. The microwave door must absolutely latch and create a seal when closed. (Never use a microwave with a faulty door.) 2 inches, it is an FDA regulation that only 5 milliwatts of microwave radiation per square centimeter can be read at this distance. This is a minuscule amount, but to be safe, stay at least 2 inches away.
For my kids? It’s two feet just to play it safe, and because I know about the ‘inverse square law’: http://en.wikipedia.org/wiki/Inverse-square_law
Hello Aurora,
1.Does this experiment alter the nutrition of the grape?
2.What is the true effect on food that is microwaved verses cooked in the oven or stove top?
3.Does the microwave add radiation to the food that we eat?
4.Why does meat in the microwave turn gummy in texture?
5.How are vegetables able to retain there color when cooked in the microwave?
6.What makes a container microwavable?
7.Does the chemical make up of microwaveable containers end up getting altered into something different after multiple uses?
8.Is it true that plastic wrap causes cancer when used in the microwave to heat or cook food in the microwave?
9.Is it save to stand right in front of the microwave and watch your food cook?
My children and I hope to hear your answers soon!!! Thanks!
Disappointed that we couldn’t turn off the light in our microwave… but we could still see the plasma and the spark. Pretty cool. Thanks! -Liz (mom)
We also smelled the ozone stuff. -Ben
That was cool! -Kate
Wow!!! Super cool! My sisters and I tried it, and it worked! But it smelled awful. Why is that? Can plasma come in a gas form too? ~ Isabel
I’ve heard from kids that have good results using cherry tomatoes. No, it doesn’t matter the shape of the food, but it DOES matter the water content. 🙂 Happy experimenting!
Aurora
HI I’d like to say that this is a great experiment! I kept stumping my sister. She thought I was making lightning in the microwave! I do have a question, does this work with any other type of foods? does it matter what shape the food is?
-Nicole’s daughter
Wow!!! Super cool! My sisters and I tried it, and it worked! But it smelled awful. Why is that? Can plasma come in a gas form too? ~ Isabel
My kids, daughter 11 and son 12 loved this. It worked great with purple grapes, and they did a lot of purple grapes that day. Had to even pull in the public school neighbors to show what they were doing for science.
Me and my little 6yr old brother did this today . IT WAS SO COOL !!!!!!!!
Reyna age 10.
my mom got mad at me and the plasma was big! o.o and a a little fire was in the plasma…
wait I was suposed to use an old microwave?!?! woops I used a brand new one… hopefully it still works fine…
Hi this is Madeline. We tried a purple grape but that didn’t work. Then we tried a green grape and that worked. We tried some more green grapes but they didn’t work, so we took our turn table out and put the plate in the back on the left hand side, and the grapes got turned upside down somehow too. And that was what worked the best. It was a very fun and interesting experiment!:)
Me and my little 6 yr old brother did this . It was awesome! The first time it made a little poof of flame. :]
Awesome! It worked the first time and then it didn’t work. We are doing this afternoon with an after school group. We’ll be trying the cherry tomatoes too.
This didn’t work for us (just bubbles), however I noticed that you commented to move the grape around the microwave, so we will try that tomorrow! My kids will be excited to try it out again. Thanks Aurora!!
Yes, that’s right!
is this the same plasma in plasma tvs?
After we moved the grape to the back of the microwave, it sparked, and it was fun!!!!!!
The ‘bridge’ is the part that was ‘vaporized’ to make the plasma – it was chemically transformed in the process.
Cherry tomatoes are also popular!
Wow! This worked so well! I used a green grape and it looked awesome! I noticed that it “burned” in the bridge of skin. it was really cool! How does it work?
i love your science!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! ak :] doder
can it work on eniething els ?
It sounds like the grape isn’t in the ‘sweet spot’ in the microwave – move it around a bit. Fizzing is not quite what we’re after. Check out the comments (there are a lot) to see what other kids have tried that worked… 🙂
I can’t get it to work! The grape just bubbles and fizzes. Does it need to cook longer? I’m setting the microwave for 20 sec. We have a newer type microwave.
super cool my boys loved it
This is cool but purple grapes don’t work. Green ones work great
Grape juice conducts electricity. Each grape half is a reservoir of grape juice connected by the thin tab of grape skin. The microwave produces energy that causes electrical current to move back and forth between the grape halves through the skin that connects the two halves. As current flows, the thin skin connector between the two halves dries out and burns up, and is unable to carry current any longer. The grape juice is still creating electricity and it wants to flow anyway. As more energy is absorbed, the heat increases (30000F). The current becomes so strong that it finds a way to flow to the other side of the grape by arcing across the gap. At this temperature and with all that arcing, the sparks fly. This is also where the electrons start zinging about. Ionized oxygen (0-1) is released as a product of plasma formation and immediately seeks out oxygen molecules (02) to bond with. This creates ozone (03). The bad smell in the microwave is ozone being generating. As you have been taught, it is true that electrons don’t exist on their own. As they zing about, they are looking for something to quickly bond to.
Loved this!!! 3/4 worked! My boys thought this was amazing! Thanks for making science come alive! 🙂 Interestingly enough, we watched the show One Way Out not 5 minutes later about plasma. Not intentionally, mind you. Such fun!