Electromagnetic Waves Can travel through empty space (non-mechanical) Produced by charged particles in motion or by the decay of subatomic particles Travel as little bundles of energy called “photons” All travel at the speed of light in a vacuum c = 300,000,000 meters/second (186,000 miles/second) Have properties of both waves and particles

Radio Waves Lowest Frequency and Energy on EM spectrum Largest Wavelength on EM spectrum AM radio (Amplitude Modulation) TV signals FM radio (Frequency Modulation) Aircraft communication Can be used to study outer space

Microwaves Used for some communication (cell phone signals) Can penetrate clouds, haze, and weather Interacts with water molecules to heat food Theory suggests Spread throughout the universe from the Big Bang Used in RADAR -RAdio Detecting And Ranging Doppler RADAR uses microwaves to see moisture in the atmosphere

Infrared Waves TV remotes use infrared waves Carry heat energy Can be used in thermal imaging Night vision goggles Used by military and emergency responders Satellites can see temperature readings on earth from space

Picture from space with infrared satellite

Visible Light EM radiation that can be detected by the human eye ROY G. BIV

Ultraviolet Waves Given off by the sun Harmful to humans- sunburn/ skin cancer/ eye damage UVA and UVB are both harmful Blacklights and tanning beds give off UV waves Absorbed by ozone in our atmosphere which protects us Can be used to purify water Can still penetrate clouds!

X-rays Found by accident: X-rays left marks on a screen that wasn’t exposed to light X-rays penetrate flesh but get absorbed by calcium in bones They are created by high energy electrons changing orbitals. Large amounts are harmful to humans They are given off by the sun and other stars Most X-rays from space get absorbed by our atmosphere Can be used in other types of imaging to see inside the body

Gamma Rays Highest energy and frequency on EM spectrum Shortest wavelength on EM spectrum Given off as a bi-product of nuclear decay and radioactive atoms Able to kill living cells- good and bad Can be used to fight certain types of cancer and prevent artery blockages Like x-rays, they get absorbed by our atmosphere