1. The Electromagnetic Spectrum
The Electromagnetic Spectrum (EMS)
Radio Waves – longest waves, lowest energy.
Microwaves
Infrared
Visible Light
Ultraviolet Light
X-Rays
Gamma Rays – shortest waves, highest energy.

2. Electromagnetic waves
Energy carried by an electromagnetic wave is called radiant energy.
Waves are formed when a charged particle vibrates.
Most of the Earth’s radiant energy comes from the Sun.
Electromagnetic waves can travel through empty space.
Short wavelength = high energy.
High frequency = high energy.
This Photo by Unknown Author is licensed under CC BY-NC-ND

3. Radio Waves Longest Wavelength, lowest energy Radio and Television
Digital transmission is clearer than analog.
A carrier wave carries sound or images.
Broadcasting = sends information in all direction

4. Infrared Radiation Infrared Felt mainly as heat
Can make images of Earth.

5. Visible Light Narrow range of wavelengths that we can see! ROY G BIV
Red
Orange
Yellow
Green
Blue
Indigo
Violet

6. Ultraviolet Radiation
Makes people tan
Causes sunburn and skin cancer
Mostly blocked by ozone layer.
Ozone layer is threatened by CFCs (Chlorofluorocarbons) that come from air-conditioners, refrigerators, and foam packaging.
Can be used to kill germs on medical tools.
7% of sun’s energy comes as UV rays.

7. X-Rays A lot of energy. Too many can cause cancer.
Pass through soft tissue but stopped by denser items.
Can be used to see broken bones.
Dentists use to detect cavities.

8. Gamma Rays Most powerful Highest frequency Shortest wavelengths
Deadly in small amounts
Used to kill cancer cells
Also used in PET scans to track breakdown of a chemical tracer in your body.