By R. Benrey
Posted 06.11.2012 at 12:29 pm 8 Comments
This article originally appeared in the April 1968 issue of Popular Science. You can explore more of our archives--stretching back 140 years--here.
A baked potato in six minutes flat...piping-hot biscuits in about 20 seconds...a sirloin steak (rare) in five minutes--these days my wife can cook elaborate dinners, made with fresh food, in less time than it takes to read the directions on a TV dinner. Her secret is our new microwave oven, made by International Crystal Mfg. Co., 10 N Lee St., Oklahoma City.
Far be it from us to deride anyone’s childish fascination with blowing stuff up in a microwave—a foolhardy nerd rite of passage if ever there was one—and what better place to exhibit dangerous, potentially expensive shenanigans than YouTube? The experiment is simple. Take a seedless grape and slice it lengthwise, making sure (this part is important) not to cut all the way through, so you leave a little bit of skin connecting the two halves. Put it face-up in a microwave, and blam: fireworks!
So what the heck is going on in there? Grapes are chock-full of electrolyte, an ion-rich liquid (a.k.a. “grape juice”) that conducts electricity. Each grape-half serves as a reservoir of electrolyte, connected together by a thin, weakly conducting path (the skin). Microwaves cause the stray ions in the grape to travel back and forth very quickly between the two halves. As they do this, the current dumps excess energy into the skin bridge, which heats up to a high temperature and eventually bursts into flame. At this point, the traveling electrons arc through the flame and across the gap, ionizing the air to a plasma (which itself can conduct electricity) and creating the bright flashes you see.
And that notion about poisonous gas tainting your roommate’s Hot Pocket? Well, the guy’s talking about the ozone generated when the air inside the glass is ionized. “Poisonous” might be too a strong word in this scenario (a little ozone definitely won’t kill you), although high concentrations of ozone can oxidize lung tissue and have been known to cause asthma in urban inversion-bowls like L.A. and Mexico City.
Again, DON’T TRY THIS AT HOME. Microwave ovens + biological capacitors = bad news. —Martha Harbison.
Our scientist zaps tin and silver, shatters glass, and arcs his oven to prove a point.
By Theodore Gray
Posted 09.01.2003 at 8:00 pm 5 Comments
There is an entire subculture of people who derive pleasure from putting strange things in microwave ovens, things that microwave oven manufacturers would most strenuously suggest should not be put there. In the hands of these people, table grapes produce glowing plasmas, soap bars mutate into abominable soap monsters, and compact discs incandesce. As a scientist, I'm enthralled by such phenomena (particularly the grapes), but somehow I've always found the subject a bit unsatisfying: Cool, but what is it really good for?
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.