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Fun with James Onde

Fun with James Onde

For all who don't know: James Onde is the name of my microwave oven. Since I always made experiments with other persons microwaves, one day they had the nice idea to donate a new one to me. It is a 800W model (Moulinex), which seems to be enough power for most funny applications. My microwave laboratory is also equipped with a multispectral radiation recording unit (optical range) for documentation purposes. In this sense I found the grill function of the oven quite practical, as it allows the correct focussing of the recording unit before the actual experiment starts.

The following experiments are divided into two categories: basic and advanced. Basic means that they are only fun, with no big risk for the oven and/or its environment. Nevertheless, extensive cleaning operations might be necessary afterwards. On the other hand, the results of experiments marked "advanced" are uncertain. Anything can happen, your oven might blow up, you might get heavily injured by radiation and you might even produce a black hole which swallow up your whole quarter. You have been warned (btw: most of the funny experiments are advanced).

Featured experiments (more coming soon):

Overheating an Egg (basic)

Description: Microwave experiment for beginners and other mudlarks. Nice to shock your mother, astonish some friends and to find an occupation for the afternoon (cleaning up the mess).

Setup: Just place a raw egg somewhere in your microwave oven, and switch it on with full power. Wait up to two minutes until you hear an explosion and see all the mess.

Results & discussion: The egg explodes after a while. The microwaves heat up the egg more and more and a establish a high pressure inside, causing finally the explosion. Even if the egg gets cracked during the process usually it works. Just wait. Hint: I preferred a protection in form of a reversed glass tea pot, but it only worked partly well (see Fig. 1).

Fig. 1: Egg roasted in the microwave (click to enlarge).

Mapping energy nodes (basic)

Description: The energy distribution in a microwave oven is usually not homogenous and your food heats up very much at some points and stays nearly cold at others. There are some professional models which include some additional technique to avoid this effect. But usually it is simply solved by a turning plate, which assures that each part of the food gets warm. I always asked myself how to image these standing waves in the oven. This is just a first approach using several layers of liquid protein.

Setup: First you need a big packet of raw eggs. Pitch two of them and mix the liquid content until it reaches an uniform color. Distribute the protein mix on a plate, for example the turning plate of the oven itself. Remove the turning mechanism and place your microwave detector plate in the oven. Run the microwave until you see some spots of solid egg protein appearing on the plate. Repeat the prior steps, but place the detector in different heights, for example by putting some solid objects under the plate.

Results & discussion: The results can be described best with images, shown in Fig. 2. The distribution of the hot spots is astonishingly not as regular as it can be expected. For the ground level, only two big spots on the left side can be observed. This is the opposite side of the microwave emitter inside the oven placed top right. With increasing height, the hot spots wander first more to the middle, and the concentrate more towards the front window. In all heights, a great amount of small hot spots can be observed.
Concluding it has to be mentioned, that this experiment might not be well suited for analyzing the energy distribution in the oven. It is not clear how far the egg layer itself influences the distribution. This will be addressed in further experiments.

Fig. 2: Mapped energy nodes at heights of 0cm, 5cm, 8cm, 10cm and 13cm (from left to right) above the ground level of the microwave oven. Total height of the cooking chamber is 18cm.

Burning CD's (basic / advanced)

Description: This is the classical microwave experiment and only here for the sake of completeness. If you dont own a CD writer, burning CDs in the microwave is a very nice and cheap possibility to put content on your CDs. The resulting CDs are always good for birthday presents and similar purposes. Also good to get rid of all these free AOL CDs.

Setup: Place the CD horizontally on something like a cup in the middle of the oven, at best with the unprinted side up. Alternatively you can also remove the turning plate and attach the CD vertically. Switch on the microwave for a few seconds until you see something going on on the surface of the CD. Switch off immediatly after that!

Results & discussion: On the CD something like a miniature thunderstorm goes on for a short moment (shown in Fig. 3). After cooling down, the CD surface shows kinds of fractal structures, as well as sometimes funny color changes. The strength of the effect varies strongly with the particular CD. I usually get best results with mostly unprinted CDs. Green CDWs are also very nice because of an interesting change to orange color afterwards. Nevertheless, the best of all I ever had was a Windows 2000 installation CD!
The microwaves seem to induce strong currents in the thin metallic layer of the CD, causing it to melt down and to produce these nice little thunderstorms. Very quickly this stops, and only some small spots seem to absorb all the energy. As they heat up quickly, the plastic of the CD melts and the whole thing starts to smoke and smell heavily. Because of this experiment is partly advanced: Stop the microwave when it start to smoke, or you wont want to prepare food in it again.

Fig. 3: Miniature thunderstorm on a CDW surface (click to enlarge).

Light-bulbs (advanced)

Description: This is a visually very impressing experiment, although I suspect that it might be quite bad for the microwave oven. I has two benefits: A very nice buzzing noise produced by the oven, combined with flickering colors of different kind. Perfect for rave parties when combined with a cool bass beat. Also good in the case of emergency that you run out of a proper socket for your light bulb and still want to have some light. Disadvantages: Light bulb might burst, spreading small sharp-edged particles of glass all over the oven.

Setup: Very simple. Attach a light bulb of choice to some kind of mounting device (I used a cup), and place the whole thing on the turning plate. Switch on the oven. For making photos, it is better to remove the turning plate and to put everything on a fixed place for better focussing. As the enery distribution inside a microwave oven is not homogenous, this might need some adjustment before finding a good position.

Fig. 4: Orignal experimental setup. When the turning table is not uses, it is necessary to find a good position for maximum performance.

Results & discussion: For a short moment, all the metallic parts inside the bulb glow up brightly, before they burn through and melt mostly (Fig. 5). After a few moments, instead the whole inside of the bulb starts to glow in changing colors from violet to orange while the oven starts to buzz loudly (Fig. 6) This goes on for a while, until usually the bulb burst, stopping the effect. With small French bulbs I observed a different effect. They seem to be stable enough not to burst, instead the glass melts at one point, and the glowing gas shoots out with a kind of darting flame (Fig. 7). Don't touch the bulb after stopping the experiment, it is extremely hot. Wait for some minutes to analyse the interesting structures on the bulb.
Obviously, the energy pumped into the bulb in the bulb is large enough to ionize the inert gas contained in it, maybe initiated by the glowing metal. Once some gas is ionized, energy is absorbed directly in the gas, keeping the effect running. In the meantime, the bulbs heats up more and more, especially at its lower end where the metallic socket is placed, causing the final burst or meltdown.

Fig. 5: Shortly after starting the microwave, all metallic parts start to glow before they melt and the glowing is limited to the lower end of the bulb.

Fig. 6: Then the gas inside the bulb starts to glow. The glowing zone is pulsating, getting bigger and smaller while changing again and again the color.

Fig. 7: If the bulb does not burst, after a while the glas melts at one point, and the glowing gas shoots out suddenly.

Plasma Foil (advanced)

Description: This is also a visually quite impressive experiment. It does not only produce funny light effects, but also smoke, bad smell, as well as big dancing flames inside the microwave. The original setup can be quite small, therefore this experiment is perfectly suited for annoying people you don't like by leaving a small piece of plasma foil somewhere in there microwave. Disadvantages are the same as the advantages: Smoke and bad smell in the microwave. But lot of people seem like barbecue taste in their food....

Setup: You need a kind of metalised plastic or paper foil. These foils are sometimes used for chips bags, or to close new glasses of instant coffee or nougat creme (under the cap). Take care that really metal is used and not only a cheap look-alike. In the described experiment I used one of a Nescafe instant coffee, seems to be a quite good choice. Place the foil on something robust in the microwave, and start the oven. Additionally you might want to place a kind of security above the setup in order to limit the extension of the emerging flames. I used a tea pot out of glass, which was placed reversed above the coffee cup holding the foil. If the tea pot has some metallic part (common), remove them before!

Results & discussion: Quickly the foil starts to burn, at the beginning only on one small spot. The emerging flames are very big, and seem to get amplified by the microwaves (Fig. 8). But rapidly this region extends, and the flames eat up the whole foil, leaving only some carbonized rests. Additionally, from time to time, glowing balls pop out of the foil and rise up to the ceiling (Fig. 9). They have a color between blue and violet (at least for Nescafe foils), and survive alone up to 5-10sec, while making a buzzing sound. During this time the flames on the foil seem to be of normal size. When the foil has disappeared, the reaction stops of course.
A repeated experiment with a plastic instead of a glass protector didn't deliver many new results. The flames seem to be quite hot, as the plastic melted down quickly, producing a really bad smelling smoke not only in the oven, but all over the lab (Fig. 10 & 11).
An explanation for the observed effects is not easy. The metal on the foil heats up quickly, setting the plastic/paper underneath to fire. Any fire in microwaves ovens with carbon involved is really fun, and so it is here (see other experiments). I don't know how these "plasma balls" are forming, but I suspect that they consist mainly of ionized carbon. They seem to survive because they absorb most of the oven's energy (flame on foil gets normal), but it is not clear how they manage to keep together. I heard that lot of people believe that this effect has something to do with the mysterious ball lightning.

Fig. 8: Amplified flames shoot out of the foil shortly after switching on the microwave oven, quickly eating up all the foil.

Fig. 9: Glowing balls pop out the the burning foil and resist up to 10sec on the ceiling. The have a blue color and buzz loudly.

Fig. 10: Same experiment, but with plastic protector (mineral water bottle). Finally not a good idea....

Fig. 11: Since then, we have a new mascot in the microwave lab. Isn't it cute?