Plasma Grape
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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This is such an awesome expirement! My mom was scared it would ruin her microwave.
sevy keble
sorry I didn’t say this in my last comment, but why does the grape emit plasma and make flashes?
sevy keble
Right – there’s no damage to the microwave with this one as long as you keep an eye on it (and stop it before it turns into a mighty fireball), and it’s best done with the lights off.
As for your other question, remember that plasma is HOT HOT gas, and in this case, HOT HOT air (with a bit of water vapor). Here’s how you superheat the gas using a grape: Grapes are made mostly with juice that conducts electricity (we’ll cover electrolytes in a later lesson, but think of how salt water conducts electricity for now). The grape halves are like little cups full of this conductive juice connected by a tiny bridge (the part that you didn’t cut all the way through). When you hit the ON button on the microwave, the energy being shot at your grape moves the electrolytes across the bridge very quickly, which heats up the bridge until it bursts into flame… and when this happens, the electrons that are traveling through the flame arc across and ionize the air around the grape and a burst of bright plasma shoots up. If you watch carefully, you will see two flames shoot up, not one. Happy Experimenting!
Wow. This is awesome! I have never “made” plasma before! :p
Yes – but be careful… you can singe your microwave if you’re not watching.
I never knew what Plasma was and this explaines it really well!!! Dose it hurt you if you eat it after it has burned?
-Holly Thomson age11
I don’t recommend eating the project your doing, as a general rule for science experiments…
We have been trying this all afternoon and can’t get it to work. All it’s doing is bubbling. It’s a new microwave. Should we turn down the power of it? Would love to hear what we are doing wrong. Thank you, Michelle
When I did it at night, it worked fine and we could see it well. We had all of the lights off, except the automatic in-microwave light. When we tried it again the next afternoon, ours was just bubbling, too. I think that it must have “made” the plasma already, but we could not see it because it was too light. Maybe you should try it at night… hope this helped a little.
Debra Thomson
If it’s bubbling, it means that it’s not in the right location in your microwave. Just open the door, move it an inch or two away, and try again, Make sure you haven’t torn the thin bridge-skin, though, or it won’t work at all.
I’ve been learning about nuclear fission and nuclear fusion lately. In my curriculum, it said that million-degree temperatures must be reached for nuclear fusion to occur. And, once you reach those temperatures, the atoms lose their electrons and exist as ions and free electrons. And that is when plasma is created. So, when we did the plasma grape, did we make million-degree temps? If so, Wow. That is amazing.
Thank you so much!
-Stephanie T.
I love to do this experiment! Who would of guessed that grapes can make plasma! Are there any other foods that can make plasma?
Holly Thomson age 11
There are a few others, but grapes have the biggest ooh-ahh factor. Have fun!
Fusion is when you smoosh the atom cores together, and fission is when you break the cores apart. In our experiment, we’re stripping off the electrons that zoom *around* the core of the atom. A plasma is basically a gas that is so hot (aka has so much energy) that the electrons shake loose and zip around on their own. And you’re right – you need MUCH more energy than a microwave can give you to produce nuclear fusion… something on the order of the SUN ought to do it.
(On planet Earth, you need a bolt of lightening to get million-degree temperatures.)
We loved the experiment! It’s one of the first ones we’ve done and it was really cool! Is this the same kind of plasma that powers plasma tv’s?
When we tried this experiment at first it didn’t work. All it did was bubble and smoke. We tried a different grape and used a paper towel to blot off the excess juice and it sent of a few sparks but it didn’t work as well as it did in the video. We have a really nice, high power microwave. We used large green grapes, if that makes a difference. We also noticed that when we didn’t blot it with a towel that the juice boiled over across from side to side and we were wondering if maybe that changed the reaction because the energy could cross more easily. We also tried it at 50% power and it didn’t work at all. (We still blotted it with a towel.) We also found that 12 seconds was not nearly long enough and that it took 20-30 seconds before it made sparks. Thanks for the help!
-A, age 12
We just tried it again only we put it close to the edge of the plate and we got a huge reaction!! The thing was, though, is that it sent off a few more sparks in the middle of the grape than usual, but the big reaction didn’t actually come from the grape. It looked more like it came from this grate in the top that won’t come off so it’s really hard to clean. This time it took about 15 seconds.
P.S. It’s REALLY cold and dry where we live, so we were wondering if the humidity and/or temperature in our house could have effected the reaction in any way? Thanks!
-A, age 12
You’re right – it’s the hot gas slightly ABOVE the grape that ionizes and POOFs! And no, temp and humidity don’t have a lot to do with this experiment, as it’s inside your microwave and the ionization temp is so high and the grape is so wet (mostly water) Good work!
To quote my boys, “AWESOME!” We tried it first of all with a seeded grape that had been thawed-didn’t work. Next we got seedless red grapes-it worked quite well. Now they want to know if you can have a plasma apple! ( I think they think-Bigger fruit=Bigger flash!) Are there any other fruits that would be safe to try? Thanks!
So glad you’re enjoying the experiment – this is one of the more flashy ones! And sadly, an apple doesn’t have enough juice to work… but don’t take my word for it – try it (and others) and let me know how it goes! Happy experimenting! ~Aurora
We did this experience 4 times. The second time worked the best. It looked like a plasma globe in a microwave. We learned that if you don’t open it enough it won’t work. It shot a ring of flame to the top of the microwave (mom was worried
) . It was really cool. Martin
We were dismayed to read your description of microwave works. Microwaves are short range, high power radio waves, not light beams. Do you have a particular reason for using this description? The experiments sound like fun, but we do not want to be learning things we will have to un-learn later.
Thanks for writing. And yes, you’re right that microwave waves are part of the electromagnetic spectrum, which also includes visible light, x-rays, gamma rays, and radio waves. The trouble arises when kids hear the word “radio waves”, as most folks will immediately think of sound waves.
To introduce kids to the idea of light (which is more difficult to understand than sound as the ideas are more abstract), we first make the distinction that radio waves are NOT sound waves (as it might appear because of the name), so this analogy of “light beams” sometimes helps. When we introduce light energy ideas to kids, we talk about how microwave energy, TV remotes, etc are all light waves, which travel and act differently than sound waves.
The photon can be described as having four distinct characteristics: intensity, wavelength, time shift, and polarization. Feel free to add or augment any of the material we offer as you see fit – there’s more than one way to understanding the scientific principles!
I love this! 5 stars
WOW this is such a cool project!
I have not actually done this project yet but it is definitely on my calendar this month!
2 questions why does the grape make such a bright light and how?
Liam F. =D
Do the experiment first, then read the comments here… and go over the quick reading for Unit 3 about plasma… and THEN see if you can puzzle it out… I promise to answer more soon after you’ve had a chance to roll around with it.
this was so sweet i think it might have blown up, but other than that not much damage to the grape other than some burns
Lukas 8
OK WE had a slow start, then read the comments and kept trying.. Well we got flames! Now of course they are doing it with 3 and 4 grapes on the plate…Hope we do not catch the house on fire! They love it, thanks<
ok, now they are going completly around the plate and grabbing anything eles they can from the fridge. I am a bit afraid! But We are using the old microwave, so I am not to worried….It was going to the next yard sale anyway.
this is soooooooo much fun we love this thank you so much can not what to try the other ones emma
ok, just trying to figure it out. We did the grape experiment, but I wanted to figure out what “unit” is is in. But cant seem to find that information.
My kids of course are seeing some of the fun stuff they can do, built the catapult, and t-did the grape one, but again, when I look at lesson
plan and try to see where it fits in, I cant put it anywhere. I am wanting to maybe lean toward the same lessons for the experiments
so we can make sure we are learning something, but cant find the unit. Thanks for your help. is there a experiment list and then a corresponding
unit/lesson it belongs too…
thanks again, Carolyn Pecharka
Hi Carolyn, Here’s an easy way to figure out which lesson an experiment belongs to – look in the upper right – do you see how it says “Density Video, Density Reading, Density Experiments…” etc? The plasma grape experiment is part of the Density Lesson, which is in Unit 3. When you hop around the site, this menu in the upper right changes. Because we’ve pulled a few of the experiments out and stuck them in the “getting started” area, it can be confusing as to which unit they really belong to, so this is a way to tell where you are. So to get more experiments like the plasma grape one, simply click “Density Experiments” and you’ll get all the ones in that lesson. When you click “Density Reading” you get the background info about it, and “Density Video” walks you through that this lesson is all about.
If you haven’t already watched the video for new members (main page, upper right), you might find that a valuable use of your time, as it goes over how to navigate through the site. Does that help?
I really appreciate the videos with this program. We do not have a microwave, so being able to watch the videos is almost essential to the children understanding what is happening in the experiments! Thanks very much!
wow this is such a cool activity! not all of the times it worked because our microwave is old. thanks again.
Liam floyd 11
It does matter WHERE in the microwave you stick the grape!
Have fun!
This morning we did the grape experiment. My 5 yr old thought it was AMAZING that it made sparks.
We’ll try the soap experiment this weekend I think. We are enjoying the experiments, although I’m hoping as the summer goes on I’m better about consistently doing one or more each day instead of every few days. Thanks again!
We did this yesterday with a group of 6 kids and the boys thought it was the coolest thing so they took a whole plateful of sliced grapes when I wasn’t really paying attention and as I heard the microwave on again I looked to see quite the show! I wasn’t sure if my microwave would still function after that. The flames joined together to make bigger flames so the microwave was quite lit up! The kids said it was awesome!
We did the plasma grape again, after heading to the store for a bunch of grapes.. fortunately grapes were on sale. This is becoming the ‘must show and tell’ as soon as someone comes to visit.
That was great ! What would happen if I left it on longer than 12 seconds?
Why do you see a bluish yellowish section in the middle of the grape?
That’s the plasma you’re seeing – good eye!
Have you tried it? Keep an eye on it in case it starts to burn…
I looked at the Plasma Grape video and was wondering what causes plasma in this experiment. I’m sure it has something to do with microwaves but I am really curious as to how it works. Could you explain, please?
I also love your science curriculum but my children are still very small – ages 5, 3, and 1. So I was wondering if there is a way to use it with preschoolers. Should we just do experiments without explaining they why’s and what’s of the science involved?
I saw somewhere on your website you mentioning that you plan to introduce biology at some point. Do you know when?
Hi Tamara – you can read up on how it works by reading the information section and the comment section for this experiment. That’s where you’ll find lively discussions about what’s going on and other things to test out that other families suggest.
You can definitely use these science activities with young children – we’ve had five year olds build the robots in Unit 10 with adult help, in fact!
Great activities you can do with younger kids include: Roller Coasters, Airplanes, the Bat Kite, and Slime.
You can expect to see biology beginning to be released (there will be several units) in Winter 2011. We are just now completing work on advanced Chemistry (Unit 15) and Computer Technology (Unit 16), so it will be sometime after that. For the latest information, click on our syllabus.
Aurora-Are you experiment directions written up anywhere in a format that can be printed and followed? My computer internet connection gets lost in certain places in my house. Thanks. Shannon
A few of the experiments are written up in the Lesson Plan, but most are online. About half of the experiments have written instructions directly under the video player, but the rest are all on video, as some of these were too long or difficult to describe by written instructions only. Hope this helps!