1. The Electromagnetic Spectrum

2. The waves of the spectrum Herschel used a prism to separate the wavelengths present in sunlight. Herschel used a prism to separate the wavelengths present in sunlight. The colors he produced were red, orange, yellow, green, blue, and violet. The colors he produced were red, orange, yellow, green, blue, and violet. Noticed the different color lights had different temperatures, so must have different energies. Noticed the different color lights had different temperatures, so must have different energies. The entire range of frequencies is called the electromagnetic spectrum. The entire range of frequencies is called the electromagnetic spectrum. Includes radio waves, microwaves, infrared waves, visible light, ultraviolet rays, X-rays, and gamma rays Includes radio waves, microwaves, infrared waves, visible light, ultraviolet rays, X-rays, and gamma rays

3. The electromagnetic spectrum

4. Radio waves Longest wavelengths, lowest frequencies. Longest wavelengths, lowest frequencies. Wavelengths can be the size of buildings. Wavelengths can be the size of buildings. Used in radio and television, microwave ovens, and radar Used in radio and television, microwave ovens, and radar

5. Radio Voices that have been changed into electronic signals are coded onto radio waves and broadcast. Voices that have been changed into electronic signals are coded onto radio waves and broadcast. Use amplitude modulation (AM) and frequency modulation(FM). Use amplitude modulation (AM) and frequency modulation(FM). Amplitude modulation uses a constant frequency and changes the amplitude of the wave. Amplitude modulation uses a constant frequency and changes the amplitude of the wave. Frequency modulation uses a constant amplitude and changes the frequency. Frequency modulation uses a constant amplitude and changes the frequency. The radio at your house or in your car decodes these signals and changes them into sound waves you can hear. The radio at your house or in your car decodes these signals and changes them into sound waves you can hear.

6. Television These radio waves carry information for pictures and sound. These radio waves carry information for pictures and sound. Your TV picks up the signal and turns it back into sound and pictures. Your TV picks up the signal and turns it back into sound and pictures. TV reception can be affected by weather. TV reception can be affected by weather. Satellite TV gets its signals from TV broadcasts that are sent to satellites in space. Satellite TV gets its signals from TV broadcasts that are sent to satellites in space. Cable TV receives the signals for people that do not have a satellite dish and sends them to their home. Cable TV receives the signals for people that do not have a satellite dish and sends them to their home.

7. Microwaves Shortest radio waves Shortest radio waves Used in microwave ovens and cell phones. Used in microwave ovens and cell phones. Cell phones work the same way radio waves do. Cell phones work the same way radio waves do. Microwave ovens use the energy in the wave to heat up food particles. Microwave ovens use the energy in the wave to heat up food particles. Microwaves only penetrate the surface of foods which is why you have to let the food sit so the food can be heated by conduction. Microwaves only penetrate the surface of foods which is why you have to let the food sit so the food can be heated by conduction.

8. Infrared waves Shorter wavelengths than radio waves Shorter wavelengths than radio waves Used as a source of heat to discover areas of heat differences. Used as a source of heat to discover areas of heat differences. Infrared lamps are used to keep food warm at restaurants. Infrared lamps are used to keep food warm at restaurants. You can’t see infrared radiation, but you can feel it has heat. You can’t see infrared radiation, but you can feel it has heat. Can be used to find people trapped in buildings, homes, or other structures after a natural disaster. Can be used to find people trapped in buildings, homes, or other structures after a natural disaster.

9. Visible Light The only part of the electromagnetic spectrum you can see. The only part of the electromagnetic spectrum you can see. Each wavelength corresponds to a different frequency (energy) and a different color. Each wavelength corresponds to a different frequency (energy) and a different color. Red light has the longest wavelength and lowest frequency (energy). Red light has the longest wavelength and lowest frequency (energy). Violet light has the shortest wavelength and the highest frequency (energy). Violet light has the shortest wavelength and the highest frequency (energy).

10. Ultraviolet radiation Has higher frequency than violet light. Has higher frequency than violet light. Comes from the sun. Comes from the sun. Used in health, medicine, and agriculture. Used in health, medicine, and agriculture. Helps our skin produce vitamin D which helps our Helps our skin produce vitamin D which helps our bodies to absorb calcium for our bones and teeth. Can cause sunburn, skin cancer, or damage to eyes. Can cause sunburn, skin cancer, or damage to eyes.

11. X-rays Very short wavelengths. Very short wavelengths. Used in medicine, industry, and transportation to take pictures of the insides of solid objects. Used in medicine, industry, and transportation to take pictures of the insides of solid objects. Teeth and bones absorb X-rays and appear white in X-ray photographs. Softer tissue appears dark. Teeth and bones absorb X-rays and appear white in X-ray photographs. Softer tissue appears dark.

12. Gamma rays Shortest wavelengths in the spectrum. Shortest wavelengths in the spectrum. Have the most energy and penetrating ability of all the waves of the spectrum. Have the most energy and penetrating ability of all the waves of the spectrum. Used to kill cancer cells and to take pictures of the brain. Used to kill cancer cells and to take pictures of the brain. Used in radiation therapy to kill cancer cells while not damaging healthy cells. Used in radiation therapy to kill cancer cells while not damaging healthy cells. Overexposure can be deadly. Overexposure can be deadly.

13. microwaves This is a radar image acquired from the Space Shuttle. It also used a wavelength in the L- band of the microwave spectrum. Here we see a computer enhanced radar image of some mountains on the edge of Salt Lake City, Utah. This is a radar image acquired from the Space Shuttle. It also used a wavelength in the L- band of the microwave spectrum. Here we see a computer enhanced radar image of some mountains on the edge of Salt Lake City, Utah.

14. infrared This image (courtesy of SE-IR Corporation, Goleta, CA) shows a cat in the infrared. The orange areas are the warmest and the white-blue areas are the coldest. This image gives us a different view of a familiar animal as well as information that we could not get from a visible light picture. This image (courtesy of SE-IR Corporation, Goleta, CA) shows a cat in the infrared. The orange areas are the warmest and the white-blue areas are the coldest. This image gives us a different view of a familiar animal as well as information that we could not get from a visible light picture.

15. Visible light When white light shines through a prism or through water vapor like this rainbow, the white light is broken apart into the colors of the visible light spectrum. When white light shines through a prism or through water vapor like this rainbow, the white light is broken apart into the colors of the visible light spectrum.

16. ultraviolet Our Sun emits light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns. To the left is an image of the Sun taken at an Extreme Ultraviolet wavelength - 171 Angstroms to be exact. This image was taken by a satellite named SOHO and it shows what the Sun looked like on April 24, 2000. Our Sun emits light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are responsible for causing our sunburns. To the left is an image of the Sun taken at an Extreme Ultraviolet wavelength - 171 Angstroms to be exact. This image was taken by a satellite named SOHO and it shows what the Sun looked like on April 24, 2000. Skin cancer

17. X-rays When X-ray light shines on us, it goes through our skin, but allows shadows of our bones to be projected onto and captured by film. This is an X-ray photo of a one year old girl. Can you see the shadow of what she swallowed? When X-ray light shines on us, it goes through our skin, but allows shadows of our bones to be projected onto and captured by film. This is an X-ray photo of a one year old girl. Can you see the shadow of what she swallowed?

18. Gamma rays If you could see gamma- rays, the night sky would look strange and unfamiliar. The gamma- ray moon just looks like a round blob - lunar features are not visible. In high-energy gamma rays, the Moon is actually brighter than the quiet Sun. This image was taken by EGRET. If you could see gamma- rays, the night sky would look strange and unfamiliar. The gamma- ray moon just looks like a round blob - lunar features are not visible. In high-energy gamma rays, the Moon is actually brighter than the quiet Sun. This image was taken by EGRET.