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# Electromagnetic spectrum

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### Electromagnetic spectrum

1. 1. Waves of the Electromagnetic Spectrum Blue - Highlight it
2. 2. 1. Wave Properties <ul><li>Crest: the highest point of a wave. </li></ul><ul><li>Trough: the lowest point of a wave. </li></ul><ul><li>Rest Line (Equilibrium): the mid-point position of the wave (the dotted line). </li></ul>
3. 3. 1. Wave Properties <ul><li>D. Amplitude: a measure of how high the crest is (or how low the trough is); measured from the rest line. </li></ul><ul><li>1. The greater the amplitude, the more energy a wave carries. </li></ul>
4. 4. 1. Wave Properties <ul><li>E. Wavelength: the distance from one point on a wave to the corresponding point on the next wave. </li></ul>
5. 5. 1. Wave Properties <ul><li>F. Frequency: number of wavelengths passing a given point per second. </li></ul><ul><li>Longer wavelengths equal smaller frequencies . </li></ul><ul><li>Shorter wavelengths equal larger frequencies . </li></ul>
6. 6. 2. Mechanical Waves A. use matter to transfer energy; travel faster when atoms are closer together <ul><li>B. Transverse wave: wave energy causes matter in the medium to move up and down OR back and forth at right angles (perpendicular) to the wave. </li></ul><ul><li>C. Compressional wave: Matter in the medium moves forward and backward in the same direction as the wave. </li></ul><ul><ul><li>Sound waves. </li></ul></ul><ul><ul><li>AKA Longitudinal Waves. </li></ul></ul>
7. 7. 3. Electromagnetic Waves <ul><li>Can transfer energy WITHOUT using matter. </li></ul><ul><li>Produced by electrically charged particles. </li></ul><ul><li>C. Travel faster when fewer atoms are present: </li></ul><ul><ul><li>Vacuum: 300,000 km/s </li></ul></ul><ul><ul><li>Air: slightly less than 300,000 km/s </li></ul></ul><ul><ul><li>Water: 226,000 km/s </li></ul></ul><ul><ul><li>Glass: 200,000 km/s </li></ul></ul><ul><ul><li>Diamond: 124,000 km/s </li></ul></ul>
8. 8. 4. Radio Waves A. Low-frequency electromagnetic waves with wavelengths from less than 1 cm to about 1,000 m. <ul><li>1. RADAR: RAdio Detecting And Ranging </li></ul><ul><ul><li>By measuring the time required for radio waves to bounce off an object and return to the receiver, speed and location of the object can be found. </li></ul></ul><ul><ul><li>Used by law enforcement and air traffic controllers. </li></ul></ul><ul><li>2. MRI: Magnetic Resonance Imaging </li></ul><ul><ul><li>Radio wave energy causes protons in the body to react and release energy. </li></ul></ul><ul><ul><li>The energy is detected by a receiver that maps the tissues and creates a picture of the inside of the body. </li></ul></ul>
9. 9. 5. Radio Waves in Space <ul><li>Objects in space such as stars, galaxies, and nebulae emit electromagnetic radiation in the form of radio waves. </li></ul><ul><li>Radio astronomers use large radio telescopes to collect the radio waves and study the data collected. </li></ul>Image of Carbon Monoxide gas (CO) in the Milky Way Galaxy.
10. 10. 6. Visible Light <ul><li>The range of electromagnetic waves that you can detect with your eyes. </li></ul><ul><li>Length varies from 390 billionths to 770 billionths of a meter. </li></ul><ul><li>The color we see is the one being reflected . </li></ul><ul><li>Red has the longest wavelength. </li></ul><ul><li>Violet has the shortest. </li></ul><ul><li>When all colors are being reflected , we see white . </li></ul><ul><li>When all colors are being absorbed , we see black . </li></ul>
11. 11. 7. Visible Light in Space <ul><li>Satellite data is used to create true-color and false-color images of objects in space. </li></ul><ul><ul><li>True-color : created using red, green, and blue light waves that are reflected off the surface. </li></ul></ul><ul><ul><li>False-color : created from data collected about the brightness of the light waves that are being reflected. </li></ul></ul>True color False Color Planet Uranus
12. 12. 8. Microwaves <ul><li>Microwaves range from 1 meter to 1 millimeter and therefore overlap the Radio wave band. </li></ul><ul><li>Microwaves are good for transmitting information. </li></ul><ul><ul><li>they can penetrate haze, light rain and snow, clouds, and smoke. </li></ul></ul><ul><li>C. Scientists use microwaves to look for evidence of how the universe began. </li></ul><ul><ul><li>In the 1960's scientists discovered cosmic microwave background radiation. </li></ul></ul><ul><ul><li>This radiation, which fills the entire Universe, is believed to be a clue to its beginning, something known as the Big Bang. </li></ul></ul>
13. 13. 9. Infrared Waves <ul><li>Infrared light lies between the visible and microwave portions of the spectrum. </li></ul><ul><ul><li>Longer waves are about the size of a pin head. </li></ul></ul><ul><ul><ul><li>thermal </li></ul></ul></ul><ul><ul><li>shorter ones are the size of cells, or are microscopic. </li></ul></ul><ul><ul><ul><li>TV remote controls </li></ul></ul></ul><ul><li>B. Infrared radiation is great for studying cloud structure. </li></ul><ul><ul><li>Shows more cloud detail than standard pictures. </li></ul></ul><ul><li>C. Satellites have instruments that measure and record infrared radiation. </li></ul>
14. 14. 10. Ultraviolet Waves (UV) <ul><li>UV waves are shorter than visible light; therefore, have a higher frequency. </li></ul><ul><ul><li>Not visible to the human eye. </li></ul></ul><ul><li>Have enough energy to enter skin cells and cause cell damage, even cancer. </li></ul><ul><ul><li>Earth’s atmosphere (ozone layer) blocks most, but not all UV. </li></ul></ul><ul><li>Useful in killing bacteria. </li></ul><ul><li>Can make some material fluoresce; used by Police to find seemingly hidden evidence. </li></ul>
15. 15. 11. X-Rays <ul><li>X-rays have smaller wavelengths and therefore higher energy. </li></ul><ul><ul><li>X-ray light tends to act more like a particle than a wave. They either pass through or are absorbed by the materials. </li></ul></ul><ul><li>Black holes, neutron stars, binary star systems, and supernova remnants all emit X-rays. </li></ul><ul><ul><li>X-Rays are blocked by the atmosphere & must be studied from space. </li></ul></ul>
16. 16. 12. Gamma Rays <ul><li>Gamma-rays have the smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. </li></ul><ul><ul><li>Waves are generated by radioactive atoms and in nuclear explosions. </li></ul></ul><ul><li>Gamma-rays are produced by: </li></ul><ul><ul><li>violent events such as supernova explosions </li></ul></ul><ul><ul><li>less dramatic events, such as the decay of radioactive material in space. </li></ul></ul>
17. 17. Electromagnetic Spectrum