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.