Electromagnetic Radiation EMS SPECTRUM

1. Electromagnetic RadiationEMS SPECTRUM

2. What is light? • What we think of as light, is radiation, it is just part of the Electromagnetic Radiation Spectrum. • Light travels as particles and as a wave. • The speed of light is 299,792,458 m/s (670,616,629.384 mph) • The speed of sound is about 770 mph at standard temperature and pressure

3. What is color • Color is just different wavelengths of Electromagnetic radiation • All of the colors of the rainbow are hidden in “normal” light that comes from the sun. • They can be separated, so that we can see them, using a prism.

4. What’s in the Electromagnetic Spectrum?

5. Let’s go from big to small • Radio Waves • Radio waves have the longest wavelengths in the electromagnetic spectrum. • These waves can be longer than a football field or as short as a football. • Your radio, cell phone, and walkie talkie use radio waves. • Can radio waves pass through mountains, Buildings, tunnels?

6. Microwaves • Microwaves have wavelengths that can be measured in centimeters! • The longer microwaves, those closer to a foot in length, are the waves which heat our food in a microwave oven. • Microwaves are good for transmitting information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke. • Microwaves, used for radar, are just a few inches long.

7. What is Radar? • RADAR (Radio Detection And Ranging) is a way to detect and study far off targets by transmitting a radio pulse in the direction of the target and observing the reflection of the wave. • It’s basically radio echo

8. RADARRAdio Detection And Ranging Antenna Propagation Target Cross Section Reflected Pulse (“echo”) Transmitted Pulse • Radar observables: • Target range • Target angles (azimuth & elevation) • Target size (radar cross section) • Target speed (Doppler) • Target features (imaging)

9. Radar Frequencies

10. Types and Uses of Radar • Weather radars use radio waves with horizontal, dual (horizontal and vertical), or circular polarization • Some weather radars use the Doppler effect to measure wind speeds

11. Infrared • Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. • The longer infrared wavelengths are about the size of a pin head and the shorter infrared ones are the size of cells. • Most remotes use infrared lights. • Many organisms can see infrared light. • Many night vision goggles use infrared radiation.

12. Visible Light Waves • Visible light waves are the only electromagnetic waves we can see. • We see these waves as the colors of the rainbow, red, orange yellow, green, blue, indigo, and violet. ROY G BIV • Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. • When all the waves are seen together, they make white light.

13. What is Black light? • It’s part of the electromagnetic spectrum near Ultra Violet light.

14. Ultra Violet Light • Ultraviolet (UV) light has shorter wavelengths than visible light. • Though these waves are invisible to the human eye. • Some insects, like bumblebees, can see them!

15. X-RAY • As the wavelengths of light decrease, they increase in energy. • X-rays have smaller wavelengths and therefore higher energy than ultraviolet waves. • We usually talk about X-rays in terms of their energy rather than wavelength. • X-ray light tends to act more like a particle than a wave. • X-ray detectors collect actual photons of X-ray light!

16. Gamma-rays • Gamma-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. • These waves are generated by radioactive atoms and in nuclear explosions. • Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells.