Wonkee Donkee’s lesson on microwaves
|This is Wonkee Donkee’s crash course on the electromagnetic spectrum and microwave ovens.|
|Microwaves are part of the electromagnetic spectrum, the range of ‘light’ at various frequencies and wavelengths. Light, in this instance, means all alternating electric and magnetic fields, of which visible light is a small part.|
|The spectrum varies from radiation with shorter wavelengths and higher frequencies to longer wavelengths and lower frequencies.
The seven areas of radiation on the electromagnetic spectrum are:
|Gamma ray, X-ray, ultraviolet , visible, infrared, microwave and radio wave.|
|Microwaves have a low frequency and large wavelength. They are called ‘micro’ because they have a smaller wavelength than radio waves, not because they are small (micro) waves. Their wavelength can be between 1mm and 1m.|
|Microwaves are used to transmit signals to and from satellites and mobile phones, as well as for heating food.|
|The microwave oven, or just the microwave as we all know it, is a feature in many homes and a quick and easy way to heat your food.|
|Electromagnetic radiation emitted by a microwave oven is absorbed by the water molecules in food. This causes the water molecules to vibrate and heat up, which in turn heats up your food.|
|The harmful nature of microwaves is not fully understood, and no long-term effects of continuous low-level exposure have been proven.
Intense microwave radiation has the same effect on living organisms as it does on food; the water molecules heat and expand, which causes burns.
|Microwave ovens have several safety features to prevent microwave radiation escaping:
1.Microwaves are reflected by metals, so the inside of a microwave oven is made of metal, to contain and distribute the radiation. This helps to heat food more evenly but also prevents the microwaves escaping.
|2. The door on a microwave oven is specially designed to engage operation only when closed.|
|3. The mesh that prevents you seeing clearly into the microwave is also a preventative measure. The holes in the metal sheet are not big enough for microwaves to pass through, but do allow visible light.|