Microwave Experiments for You to (Not) Try at Home
In 1946, Dr. Percy Spencer, an engineer with the Raytheon Corporation, was experimenting with a new high-voltage, microwave-producing technology called a "magnetron tube." One day in the lab, he felt a strange warmth in his pants pocket. Glancing down at his hip, Spencer noticed a small brown stain on his trousers. The Mr. Goodbar in his pocket had melted.
Curious if the magnetron had something to do with it, Spencer placed numerous popcorn kernels in the vicinity of the tube and giddily looked on as the kernels excitedly popped and bounced all over the desk. Seriously excited now, he and an intrigued colleague next experimented with an egg, which, after a short time, exploded and splattered them with yolk. The microwave oven would be conceived soon after.
Spencer made two extraordinary discoveries that day. One, he had invented a way for people to quickly, efficiently, and safely cook and reheat food. And two, he had introduced a pastime that would enthuse countless numbers of college students, pyromaniacs, and bored people everywhere. Microwave buffoonery was born.
In the ensuing decades after the microwave became readily available, homegrown mad scientists have been constantly searching for the most awesome objects to zap. Crafty individuals have tossed in everything from marshmallows, to Furbies, to fruit flies. I'm sure you're curious which objects produce the most dazzling and destructive effects, so in order to save you some time, Newton has assembled a brief list of the coolest microwave experiments for you to (not) try at home.
Bar Soap Soufflé. The great thing about microwave science is that the directions are often pretty simple. With Ivory bar soap, it's easy: all you have to do is place the soap in the microwave oven, close the door, turn it on, and watch the magic unfold (image from LoadingReadyRun).
Because ivory soap is filled with air bubbles, and the air bubbles contain water, the microwave heats up the water and causes the air trapped within the bubbles to expand. This expansion causes the soap to break apart and puff up to an enormous size!
Sparking Steel Wool. Metal doesn't always create sparks blasted with microwaves, but steel wool sure does (image from LoadingReadyRun).
Microwaves cause a buildup of charged particles in metal. These particles won't arc when the charges are spread around evenly, but when there are significant voltage differences over short distances, oh do they arc. According to Scientific American, the sharp points and tiny edges in steel wool, "concentrate charge and also cause localized drops in voltage, which together create corona discharge--a spark."
Grape Balls of Lightning! When one thinks of cool, dangerous things to microwave, metal often tops the list. Well, the humble grape utterly shatters this preconceived notion. Simply cut a grape in half, then cut one of the remaining halves almost in half, leaving only a thin layer of connecting outer skin. Once this is complete, open up the halves and set the grape in the microwave. Now, turn it on and ogle the fireworks.
What's going on here? Well, grapes contain a high amount of electrolytes, and when blasted with microwaves, the ions of these electrolytes begin to move back and forth very quickly between the two grape segments, producing a current. Eventually, a flame is produced and the traveling electrons arc through the flame, which ionizes the surrounding air and produces a ball of plasma.
(Please note that many of these experiments are hazardous and almost certainly will do damage to your microwave -- which is, of course, why we don't recommend that you do these totally awesome experiments!)