electromagnetic spectrum

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Waves of the Electromagnetic Spectrum

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Page 1: Electromagnetic spectrum

Waves of the Electromagnetic Spectrum

Page 2: Electromagnetic spectrum

1. Wave PropertiesA. Crest: the highest point of a wave.B. Trough: the lowest point of a wave.C. Rest Line (Equilibrium): the mid-point

position of the wave (the dotted line).

Page 3: Electromagnetic spectrum

1. Wave Properties

D. Amplitude: a measure of how high the crest is (or how low the trough is); measured from the rest line.1. The greater the amplitude, the more energy a wave carries.

Page 4: Electromagnetic spectrum

1. Wave Properties

E. Wavelength: the distance from one point on a wave to the corresponding point on the next wave.

Page 5: Electromagnetic spectrum

1. Wave PropertiesF. Frequency: number of wavelengths passing a

given point per second.

1. Longer wavelengths equal smaller frequencies.

2. Shorter wavelengths equal larger frequencies.

Page 6: Electromagnetic spectrum

2. Mechanical WavesA. use matter to transfer energy; travel faster when atoms are closer together

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.

C. Compressional wave: Matter in the medium moves forward and backward in the same direction as the wave.1. Sound waves.2. AKA Longitudinal Waves.

Page 7: Electromagnetic spectrum

3. Electromagnetic WavesA. Can transfer energy WITHOUT using matter.B. Produced by electrically charged particles.

C. Travel faster when fewer atoms are present:1. Vacuum: 300,000 km/s2. Air: slightly less than

300,000 km/s3. Water: 226,000 km/s4. Glass: 200,000 km/s5. Diamond: 124,000

km/s

Page 8: Electromagnetic spectrum

4. Radio Waves

A. Low-frequency electromagnetic waves with wavelengths from less than 1 cm to about 1,000 m.1. RADAR: RAdio Detecting

And Ranginga. 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.

b. Used by law enforcement and air traffic controllers.

2. MRI: Magnetic Resonance Imaginga. Radio wave energy causes

protons in the body to react and release energy.

b. The energy is detected by a receiver that maps the tissues and creates a picture of the inside of the body.

Page 9: Electromagnetic spectrum

5. Radio Waves in SpaceA. Objects in space such as

stars, galaxies, and nebulae emit electromagnetic radiation in the form of radio waves.

B. Radio astronomers use large radio telescopes to collect the radio waves and study the data collected.

Image of Carbon Monoxide gas (CO) in the Milky Way Galaxy.

Page 10: Electromagnetic spectrum

6. Visible Light

A. The range of electromagnetic waves that you can detect with your eyes.

B. Length varies from 390 billionths to 770 billionths of a meter.

C. The color we see is the one being reflected.

1. Red has the longest wavelength.

2. Violet has the shortest.3. When all colors are being

reflected, we see white.4. When all colors are being

absorbed, we see black.

Page 11: Electromagnetic spectrum

7. Visible Light in SpaceA. Satellite data is used to create true-color and

false-color images of objects in space.1. True-color: created using red, green, and blue light

waves that are reflected off the surface.2. False-color: created from data collected about the

brightness of the light waves that are being reflected.

True color

False Color

Planet Uranus

Page 12: Electromagnetic spectrum

8. MicrowavesA. Microwaves range from 1 meter to 1 millimeter and therefore overlap the Radio wave band.

B. Microwaves are good for transmitting information. 1. they can penetrate haze,

light rain and snow, clouds, and smoke.

C. Scientists use microwaves to look for evidence of how the universe began.1. In the 1960's scientists

discovered cosmic microwave background radiation.

2. This radiation, which fills the entire Universe, is believed to be a clue to its beginning, something known as the Big Bang.

Page 13: Electromagnetic spectrum

9. Infrared WavesA. Infrared light lies

between the visible and microwave portions of the spectrum.1. Longer waves are about

the size of a pin head.a. thermal

2. shorter ones are the size of cells, or are microscopic. a. TV remote controls

B. Infrared radiation is great for studying cloud structure. 1. Shows more cloud detail

than standard pictures.C. Satellites have instruments

that measure and record infrared radiation.

Page 14: Electromagnetic spectrum

10. Ultraviolet Waves (UV)

A. UV waves are shorter than visible light; therefore, have a higher frequency.1. Not visible to the human eye.

B. Have enough energy to enter skin cells and cause cell damage, even cancer.1. Earth’s atmosphere (ozone layer) blocks most, but not all UV.

C. Useful in killing bacteria.D. Can make some material fluoresce; used by Police to

find seemingly hidden evidence.

Page 15: Electromagnetic spectrum

11. X-RaysA. X-rays have smaller wavelengths and therefore higher energy. 1. X-ray light tends to act

more like a particle than a wave. They either pass through or are absorbed by the materials.

B. Black holes, neutron stars, binary star systems, and supernova remnants all emit X-rays.1. X-Rays are blocked by

the atmosphere & must be studied from space.

Page 16: Electromagnetic spectrum

12. Gamma RaysA. Gamma-rays have the

smallest wavelengths and the most energy of any other wave in the electromagnetic spectrum. 1. Waves are generated by

radioactive atoms and in nuclear explosions.

B. Gamma-rays are produced by:1. violent events such as

supernova explosions2. less dramatic events, such

as the decay of radioactive material in space.