By Danny Perez
Microwaves are sometimes considered to be very short radio waves (highfrequency and high-energy radio waves).
Some important properties of microwaves are:
- They are reflected by metal surfaces.
- They heat materials if they can make atoms or molecules in the material vibrate. The amount of heating depends on the intensity of the microwave radiation, and the time that the material is exposed to the radiation.
- They pass through glass and plastics.
- They pass through the atmosphere.
- They pass through the ionosphere without being reflected.
- They are absorbed by water molecules, how well depends on the frequency (energy) of the microwaves.
- Transmission is affected by wave effects such as reflection, refraction, diffraction and interference.
Mobile phonesuse microwaves, as they can be generated by a small antenna, which means that the phone doesn't need to be very big. In a mobile phone, they're made by a transmitter chip and an antenna, in a microwave oven they're made by a "magnetron".
- Microwaves cause water and fat molecules to vibrate, which makes the substances hot. So we can use microwaves to cook many types of food
Prolonged exposure to significant levels of microwaves is known to cause "
cataracts" in your eyes, which is a clouding of the lens preventing you from seeing clearly (if at all!) So don't make a habit of pressing your face against the microwave oven door to see if your food's ready!
Some research in the past has indicated that the small doses of microwaves from mobile phones might affect parts of your brain