Can you put rocks in the microwave?

Yesterday my mom got really angry with me because she found one of my socks in our microwave. She wanted to heat up my dad's dinner and then saw that I had left it in there. While she was yelling at me, I was pretty glad I hadn't told her about all the other stuff I had put in earlier.

In school we were told never to put any metal in the microwave because it can create an electric arc (and a kitchen fire as a result). Microwaves work with electromagnetic waves that heat up water molecules (at around 2.45 GHz - check out this cool article on 'How microwaves work' on Universe Today for a more detailed explanation.) But I wanted to know what else you could put in the microwave (besides tasteless ready meals) without making it explode or splitting it into a million pieces. And because at school, we only ever cover fairly regular stuff and not the more exciting options, I decided to conduct a little experiment myself.

I wanted to see if you could put a rock, an aubergine, a football, an egg, a piece of dry wood, half a loaf of bread, two grapes, some gum and a bit of rubber tyre in the microwave. So I went out, got myself a few very different types of rock, took all my other ingredients out of my room and out of the fridge and set to work.

I found out some amazing things. My grapes were sizzling hot within a few seconds, but the best thing was that - when they split open - they also created this very cool light arc. (I later found out this is due to the gas that comes out of them. Check out this exciting blog entry on www.instructables.com and someone's YouTube video of the same thing here.)

My aubergine exploded big time! First, nothing happened. But after a while, it grew in size and then burst into a thousand pieces and blew the door open. When my mom cooks them, they never explode. I guess this is because she puts little holes in them, so that the steam can escape instead of building up inside.

I tried two different types of rock. One with a lot of mud on it and another one that was pretty clean. Nothing happened to the clean one, although it was a bit damp. When I took it out, it was a bit warmer, that was all. But the muddy rock cracked open and split into four medium sized pieces! There were quite a few blue sparks, so I guess there must have been some metal in it too. The water that was left in the mud probably made it crack open when it was heated up.

My gum just melted. It was not very interesting but it stuck to the turntable like crazy. I had to use some of my dad's lighter fluid to get it off. I hope his dinner didn't taste funny because of it.

My football didn't do anything for a while but then started smoking like a chimney. After a few seconds, it also had a huge hole burnt into the side.

The egg surprised me a little. It exploded alright (which is what I thought would happen). But it was easier to clean than I thought. And it didn't blow the door open.

Nothing happened to the bit of tyre. It just melted and stuck to the turntable.

The piece of wood dried out and showed some nice bubble action. This didn't happen to the bread. But when I got out the bread, my bread and the piece of wood looked very much alike.

So it turns out you can actually put rocks in the microwave. And loads of other stuff too. But it pretty much depends on the type of rock you use and on the materials it is made of. (Most rocks consist of two or more minerals. In the UK, you can find three different types of rock: granite, sedimentary rocks and so-called 'metamorphic' kinds of rocks. Here in the south-east, we've got a lot of sand rock and chalk. Check out this cool Open University site for more info on rocks in the UK.) It also depends on the amount of water that's still in your rock. If it's very muddy or if there is water trapped inside, it will crack open or split. And if there is metal packed inside (this will only happen with non-Granite ones), you will also get a few sparks.

I have to say it was an eventful afternoon. I did enjoy putting stuff in the microwave to see how it would work. But the cleaning was not too much fun. So if you're thinking of repeating my experiment, I suggest you use things that don't leave a huge mess or stick to kitchen walls and to glass.

During my research, I found that there are people out there who would microwave anything, even their iPods. But I think that's a bit too strange for me to try. Besides, I don't think my dad would be too happy about it. He's the only one in our family who actually has an iPod.

Anyway. Here's what it would look like:

I took the egg picture from a site called http://whatscookingamerica.net/. My own egg didn't look so good after exploding.