Introduction: Microwave Science Experiments - Will It Blow Up? What Can We Stick In? Microwave Night at MITERS

MITERS is a creative heaven for MIT inventor types and practical physicists. We have build parties every Friday at 7 in N52-115, and anyone is welcome to come check it out and build something.

This build party, we got an old junky microwave from a thrift store, and put any interesting thing into it, before stripping it of its transformers and turning it into a welder.

Our microwave doesn't have a turntable, but it does have an impeller, which is a piece of metal outside the oven chamber that spins and changes the magnetic resonance of the box to keep standing waves from forming.

Picturing that, or at least keeping it in mind, will give you a clearer idea of why the grapes arc inconsistently, why the lightbulbs don't stay on, etc.

Photos and videos, courtesy of Jordi Castell, posted here so you can hold your own Microwave-It night!

You can also see the original photo/images at http://evalu29.uv.es/~jordi/build_party/

Step 1: Grapes

So, when you cut a grape in half (almost, but not quite fully sliced), they're about the same length as a half-wave of 2.4GHz radiation (which are microwaves).

That means that when you put them in a microwave, they resonate and the energy builds up until the juice boils and creates an ionized gas, and then arcs across the two halves.

We tried it with blueberries too, as they're almost the same size. It did work, but not quite as well.

They don't taste very good afterwards.

Here's what plasma physics on grapes looks like:


Step 2: Light Bulbs

If you put metal in a microwave, the metal will arc and spark. We just want to see if we can make these lightbulbs turn on, so we hide the metal in water, in a crystal chalice, which solves the arcing and sparking problem. (plastic would work just as well).

The lightbulbs have a cool repeating pattern, thanks to the impeller. If you took the impeller out, or had a turntable microwave and removed the turntable, you would get constant light from the bulbs, and could use them as an energy/node detector to find the strong and weak points of the field. From here you can clearly see why your food only thaws/cooks in some spots, and not others.

I like the lighthouse-like effect a lot.


Step 3: Neon Bulbs

We threw in little neon bulbs, too.

The glass of water is sort of like a resistor, preventing the bulb from blowing out by absorbing some power.

Or at least, that was the theory.


Step 4: Ivory Soap

What's so special about Ivory Soap?

What the heck does a bar of soap do when you put in in a microwave?

It's inexplicable, until you watch Alien, and then everything comes clear.


Step 5: CDs

Ah, an old standard.

Here's a cool view:


Comments

author
The+Boyce made it!(author)2014-11-19

will my microwave blow up???

author
The+Boyce made it!(author)2014-11-19

will my microwave blow up???

author
Lotsa+Bad+Luck made it!(author)2012-08-06

Just DON'T microwave an airbag!

author
my+wookie made it!(author)2013-05-01

oops, too late

author
jack.spigack made it!(author)2011-07-09

once i put a raw egg yolk on a plate to see how it would cook... i watched it for a few minutes but it didnt appear to be cooking so i opened the microwave door to inspect the egg yolk and within a second or two the egg yolk exploded all over the place and made a big mess i wasnt thrilled about cleaning up.... it was very awsome

author
Askabby made it!(author)2012-01-23

O my gosh thats is soooooo awsume and after u were probably like, y did this happen to me? :)

author
ilpug made it!(author)2011-11-10

I am going to do the grape thing tomorrow in the school cafeteria just for entertainment. Does it still work if the grapes are on a revolving tray?

author
Treknology made it!(author)2010-04-28

An impeller, and a turntable actually linked to the on/off cycle of the magnetron would vastly improve wave distribution.

author
technodude92 made it!(author)2008-03-29

Does the grape plasma harm the microwave?

author
a_traceur made it!(author)2009-10-07

Not really, just a ton of power drain which could cause an overheat. Plasma, If I'm correct, is atoms being stripped of their electrons. A neon light bulb uses plasma and so it's just light, and not fire.

author
Xellers made it!(author)2009-02-20

Actually, in RF circuits, everything tends to become an inductor.

author
gomiboy made it!(author)2008-10-28

I plan on doing this with the kids and a junk microwave. Would the effects look better if I take the lightbulb out of the mircowave? That way the light show would happen in the dark....

author
stasterisk made it!(author)2008-10-28

Sure, you could do that. I found that turning the room lights off was enough, and the microwave light was helpful with for seeing the grape and soap experiments

author
bullet-head made it!(author)2008-09-10

once my sister but a pop tart in the microwave still in the foil and it blew up the whole microwave jumped in the air!!!

author
SeaLion made it!(author)2008-03-08

Should try really really hot peppers, I heard they'll catch fire...

author
j626no made it!(author)2008-02-12

if you want the real reason, its because there are loads of mini air pockets in the soap (thus it floats in water...that was their initial sales pitch that got them on the market -- it would float in the bathtub while the others would sink.) The soap (as i'm sure you know) is still usable after this is done. the only thing i was curious about, is after it expands and you use it, does it last longer than the original bar would? if so, this would be great for people on tight budgets or people that want to protect the environment more (less soap down the drain). just a few thoughts.

author
surfreak made it!(author)2008-03-07

Nah, probably last about the same. This foam is less dense, so more volume, but you'd use more volume per wash.

author
Maxx1 made it!(author)2008-02-13

Cool, Just avoid using pets....lol Cucumbers work real good.

author
TimAnderson made it!(author)2008-02-12

Swank!

author
hay_jumper made it!(author)2008-02-12

RAD. Sorry I missed this one Star. When I did the grape/plasma thing I used a much larger variety of fruit and it made a huge ZZORPP! sound which sent my roommie running from the other side of the apartment all alarmed. I don't know what it's called but it's available at most bodegas around here. Next up is bronze and steel, yess?

author
ijius made it!(author)2008-02-12

try putting some rock salt or pickling salt in a bowl. i'll melt the salt + whatever if youleave it long enough.

author
GorillazMiko made it!(author)2008-02-12

I am always amazed at how little grapes can do so much besides tasting yummy.

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