ALL ABOUT

Light is a form of energy. –Also known as electromagnetic (EM) radiation. –Carried in small packets called photons. As light wavelength increases, energy decreases.

Types of Light (lowest to highest energy) 1.Radio Waves: Used in AM/FM radio, TV, cell phones. Able to travel through our atmosphere. 2.Microwaves: –Unable to pass through our atmosphere. –Used in radar and cooking. –Too much can damage cells.

3.Infrared: means “below red” –Some can pass through the atmosphere. –Used in audio/video remotes. –Given off as heat (night vision goggles). –Requires a clear view from receiver to transmitter.

4.Visible Light: divided into colors. –All able to pass through the atmosphere. –R O Y G B I V –An object’s color is determined by what wavelength (color) of light it reflects.

5.Ultraviolet (UV): –Some can pass through the atmosphere. –Can damage cells (sunburn). –Used to sterilize objects, also in black lights and fluorescent bulbs.

6.X-rays: very high energy, short wavelength. –Unable to pass through the atmosphere. –Can pass through human skin, but not bone. –Unable to go through heavy metals (like lead).

7.Gamma Rays: highest energy, shortest wavelength. –Unable to pass through the atmosphere. –Released in nuclear reactions. Produced by dying stars, nuclear power plants, nuclear decay or nuclear bombs. Can cause severe damage to humans. –In low doses, can be used to treat cancer/tumors.