A microwave oven (commonly called a microwave) is a machine that cooks food using microwaves, a type of radio wave. The idea was invented when a scientist who was experimenting with radio waves saw his chocolate bar, which he was holding at that time, melt. He then knew that radio waves could cook food and invented the microwave oven.
How to use a microwave[change | change source]
How it works[change | change source]
The microwave oven uses a magnetron. This is similar to a radio transmitter. It makes very short radio waves which go right into the food to a depth of about 2.5cm. This makes water molecules swing to and from at about 2.5 billion times a second. This heats up the molecules around it. As they heat up the heat goes to the inside of the food. This process is called conduction. This also happens in a normal oven, but the energy goes deeper so that the food cooks much faster. In an ordinary oven the energy stays mostly near the surface
Apart from this the oven has a wave guide, turntable, and a timer switch. When we place the food inside the chamber and turn the timer switch on, it sends a command to the magnetron to send microwaves as well as to the turn table to start turning. The microwave can only heat food which has water molecules ( molecules are a small group of atoms stuck together by a chemical bond. Two atoms of Hydrogen and one atom of oxygen make water. H2o ). When the oven is started it sends microwaves. These waves go and touch the water molecules. Then the water molecules start vibrating against each other at a very high speed this generates heat. The turn table moves so that the food is heated evenly.
Only fine China Bone, Glass or special plastic materials can pass heat through them. Aluminium foil can not pass heat because when the waves come to it they reflect on it and go away. The microwave does not cook food but only heats it up from inside.
Related pages[change | change source]
References[change | change source]
- "Teaching the world to ping", The Independent, Thursday 12 May 2011; Viewspaper p.16