Friday, May 4, 2007

Microwave Mayham


Got an old microwave oven laying around? Here are some fun things to put in it for hours of amusement.
Info from We-Man

1.
Take an old CD or CD-R and put it in the oven, standing up. Put it against a glass cup or so. Don't use any metal as a holder. It will look like the image shown below. Notice the difference in the pattern that will show up in the metal layer in the CD between a normal silver CD and a green or gold or blue CD-R. Make sure you don't inhale the gas that comes out of the CD. It's not too good for your health, so they say ;-] Note that the CD will be unusable afterwards !
This is actually what you see when you put a CD in your microwave oven. A closer look.
2.
Place a wooden tooth pick standing up in your oven and light the top so it burns slowly. I placed mine between the clip of a plastic pencil top. A cork will do fine too I guess. Matches instead of the tooth pick will also do but they will produce less spectacular effects. Now close the door and see what happens. You didn't expect that eh? Nice yellow / orange / green / blue fireballs going up from the stick. Uh,.... yes as you might suspect, your oven will become a bit black inside here and there. But I had no problems cleaning it up. Take care that the plastic inside your oven won't melt because of the burning stick (the plastic on the top of my oven hangs down a bit now ;-}. I also tried pieces of burning charcole and a burning piece of a beer-mat. Materials like that also work (they only need to glow, not nurn) but the tooth pick works best. The actual flame doesn't have to be big for good effects.
Fire balls like this one shoot up out of the tooth pick. 2 fire balls with a long shutter time. 1 very nice fire ball with a long shutter time. 1 fire ball with a long shutter time.
3.
The light bulb in the microwave oven. You can take an old one, it doesn't have to function anymore to give the desired effect. However, the glas has to be intact so the gas is still inside. I noticed that small bulbs won't work. I used a 230 V / 60 W one. Again you won't believe what you see ! All kinds of colors coming out of the bulb. But you should take care here. Sooner or later your bulb will explode. I tried mine for 10 seconds, let it cool down (probably not enough) then I tried it for another 10 seconds, let it cool down (probably not enough again) and then after 2 seconds after turning it on again it exploded inside the oven. The door of my oven was way thick enough, so all glass stayed inside. It's quite easy to clean up the glass and I don't think it will do much harm to your oven. However, my second lightbulb never exploded! The glas gets very hot but it won't blow up! From 2 people I received the tip to put the bulb in a bowl of water in the microwave oven to cool it down so it won't explode. It works but the bulb might receive too little energy to light as brightly as it does without water around it. I haven't tried small fluorescent lamps and flash bulbs from a photo flasher yet (because I don't have them) but I expect them to be very nice, too. If you try one, please let me know the results.
glowing light bulb (this is just a short sight; if you watch it for a few seconds you will see almost all possible colors.
4.
You got 3 minutes left? Maybe this experiment is one of the most useful ones listed here. Go visit the Amnesty International website, click "take action" and sign with your name and email address. If you also leave your phone number you will receive an SMS message every now and then to which you can reply, to sign a petition against torture. Thank you.
5.
For this experiment you need some tinfoil. I advise you to put an old glass plate or so on the bottom of your oven because the foil will get very hot. In fact, it gets so hot that it melted right into the glass plate that belongs to my oven... Now cut out a piece of about 22 x 1 cm and fold it like shown below. Wrap the two ends tight into each other.
Again, make sure not to turn on the oven for more than 10-20 seconds. Especially experiments with tinfoil will ask a lot of power from your oven and it might get hot, so let it cool down between your sessions or you might damage your oven. I didn't get my eyes hurt but I don't think looking too much into the light is good for your eyes. I expected to have welding eyes in the evening but I was lucky. As with welding, a lot of UV light (you don't see light of this short wavelength) comes free which can damage your eyes.
Burning and crackling tinfoil. Put some old glass plate or so underneath it because it will melt the glass.
6.
In the U.S. used to be a program called "Mr. Wizard's World", in which this old guy would do all sorts of scientific nonsense... And one of the programs, he put a flourescent in the microwave... Although it sounds like fun, the results aren't really that exciting.. It just lights up, like a flourescent light is supposed to. Of course, this makes sense, since the material on the inside of the glass is there to turn the ultraviolet light into visible light in normal operation, and placing it in a microwave just makes this material act in its normal way, lighting up... (emailed by Michael Parker) I can tell you a bit how it works, I think. In a microwave there's no ultraviolet light. Just radio waves at 2.4 GHz. Normally the flourescent light will transmit ultraviolet light and the white powder will make this visible light. This happens because electrons of the atoms in the powder will get excited because of the exact amount of energy (or: the exact wavelength) they receive from the ultraviolet light. When (after a short while) these electrons fall back into their lower orbit, they also transmit light, but then in the visible range, but only 1 color. So they put several different kinds of atoms in the powder, that will transmit different colors so we will see white light. Appearently, in a microwave the gas in the tube gets energy from the microwave waves (probably because the gas is conducting) and starts transmitting ultraviolet light and the powder will transmit light. Easy.
7.
This one is a little less exciting, too, but it prodices a lot of light. I took a small old neon lamp (like the ones in swithes, electrician's screwdrivers etc.). They are ment for use at 60 to 90 Volts. Normally they are used with a large series resistor. For this you just need the glass lamp. I experimented a bit with it and it seems to go best if you twist the wires into eachother and put it in (again) tinfoil. If you do not put it in tinfoil, the ends of the wires will burn up and will shorten the wires. See the left picture.
This is how I did it.
See how much light comes out of such a small lamp. Mine didn't explode, not even after 20 seconds !
8.
Last week I demolished an old laserprinter. Most laserprinters and photo copiers have a lamp inside which is not there for the light but only for the warmth. Usually they are hudreths of watts and very long and thin and located inside the drum (a rubber roller). This is how mine looks like:
This is what the lamp looks like. So I thought, hey, why not put it in the microwave and see what happens (something a real fan of this page should think this too whenever he/she gets his/her hands on something that might do something funny inside of a microwave). Well, this is what it does:
It gives a bright light. And later on the left end of the wire (lower left) starts to burn (inside the glass).
9.
My former student flat fellows discovered the Christmas tree ornament in the microwave ! It's pretty much like a CD but then it's not flat but a 3D glowing ball. Simon Oosthoek made this picture with his new digital camera:
Christmas tree ornament in the microwave, a beauty, isn't it?
10.
A former student flat fellow (Simon Oosthoek) tried a small TL tube in the microwave and it looks nice:
This is what the setup looks like. And this shows how nice it burns :-)
11.
A lot of people wrote me to put a bar of soap in the microwave. And I did :-) After 3 minutes the thing was about 5 times it's original size!
This is what the several "larval stages" look like.

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