Occasionally it is a treat to remind ourselves how remarkable some of our most common gadgets are. A typical microwave oven ramps up the electricity from a 120-volt wall outlet to an incredible 3,000 volts or more and safely cooks food in just a minute or two, yet it costs less than a pair of good shoes. And we can watch the show through the handy window.

The key component is the magnetron. Although the name conjures up hardware from a questionable science-fiction movie, the sophisticated vacuum tube generates microwaves powerful enough for military radars (for which it was originally developed). Instead of a flame or electric coil generating heat that warms food from the outside, the microwaves penetrate food and create heat from within.

Keep reading at SciAm.