Of course, you don't want things outside the oven getting heated up, which is why they are made of metal.

The microwaves also penetrate into the food, effectively heating it from within.

This is why microwaves are so good at re-heating food: rather than heating the food from the outside like a normal oven would, they heat the water within the food, so it heats up quicker and more evenly. And hot water in your food means, as the heat spreads, hot food. This excitement means it moves faster, and the water heats up. When a microwave hits a water molecule, the molecule absorbs it. Created in a device called the magnetron, these electromagnetic waves get water excited. As the name suggests these devices use microwave radiation, with a frequency of about 2.4GHz and a wavelength of about 4 inches (10.16 cm). The secret of the microwave is in, well, the microwaves. The device was patented in 1945 by Spencer for the Raytheon Corporation. Undeterred, Spencer attached the magnetron to a metal box, and the first microwave oven was born. In the first (but by no means the last) microwave cooking accident, the egg exploded, showering an inquisitive colleague with egg and boiling water. Intrigued, he used this device to cook popcorn and an egg. While walking past a magnetron being tested, an eccentric engineer called Percy Spencer noticed that the radiation melted his candy bar. As part of this research, engineers at Raytheon in the US built a large magnetron, a device that generates microwaves. The microwave oven had its origins in radar research before and during World War II. The original patent for the microwave oven, submitted in 1945. That's pretty good progress for a device that was invented by accident 55 years ago. In fact, it is thought that that by the beginning of the 21st century, over 90 percent of homes in the US had a microwave oven. One of the more recent developments in this race to taste is the microwave oven, which uses microwave radiation to heat and cook your food.īecause it uses less energy and is much quicker than a gas or electric ovens, the microwave has found a spot in most homes. Ever since humans first dropped a chunk of mammoth meat onto a fire and liked the result, we have been looking for new ways to cook things.

Microwave oven