Light The EM Spectrum

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Jayson Jennings
5 years ago
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1 Light The EM Spectrum 1

2 Spectrum of Electromagnetic Radiation Region Wavelength (Angstroms) Wavelength (centimeters) Frequency (Hz) Energy (ev) Radio > 10 9 > 10 < 3 x 10 9 < 10-5 Microwave x x Infrared x x x Visible x x x x Ultraviolet x x x X-Rays x x Gamma Rays < 0.1 < 10-9 > 3 x >

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4 Radio Waves 4

5 Radio Waves Radio waves bring music to your radio. carry signals for your television and cellular phones. 5

6 Radio Telescopes Radio telescopes look toward the heavens at planets and comets, giant clouds of gas and dust, and stars and galaxies. By studying the radio waves originating from these sources, astronomers can learn about their composition, structure, and motion. Radio astronomy has the advantage that sunlight, clouds, and rain do not affect observations. 6

7 Radio Telescopes In order to make better and more clear (or higher resolution) radio images, radio astronomers often combine several smaller telescopes, or receiving dishes, into an array. Together, the dishes can act as one large telescope whose size equals the total area occupied by the array. 7

8 Radio Telescopes The Very Large Array (VLA), located in New Mexico, is one of the world's premier astronomical radio observatories. The VLA consists of 27 antennas arranged in a huge "Y" pattern up to 36 km (22 miles) across -- roughly one and a half times the size of Washington, DC. 8

9 Microwaves Microwaves have wavelengths that can be measured in centimeters 9

10 Microwaves The longer microwaves, those closer to a foot in length, are the waves which heat our food in a microwave oven. 10

Microwaves Microwaves are good for transmitting information from one place to another because microwave energy can penetrate haze, light rain

11 Microwaves Microwaves are good for transmitting information from one place to another because microwave energy can penetrate haze, light rain and snow, clouds, and smoke. This microwave tower can transmit information like telephone calls and computer data from one city to another. 11

12 Microwaves Shorter microwaves are used in remote sensing. These microwaves are used for radar like the doppler radar used in weather forecasts. Microwaves, used for radar, are just a few inches long. 12

13 Microwaves Radar is an acronym for "radio detection and ranging". Radar was developed to detect objects and determine their range (or position) by transmitting short bursts of microwaves. The strength and origin of "echoes" received from objects that were hit by the microwaves is then recorded. 13

14 The Infrared Infrared light lies between the visible and microwave portions of the electromagnetic spectrum. 14

15 The Infrared Far infrared" is closer to the microwave region of the electromagnetic spectrum Far infrared waves are thermal. In other words, we experience this type of infrared radiation every day in the form of heat. 15

16 The Infrared Shorter, near infrared waves are not hot at all - in fact you cannot even feel them. These shorter wavelengths are the ones used by your TV's remote control. 16

17 The Infrared 17

18 Visible Light Waves Visible light waves are the only electromagnetic waves we can see. We see these waves as the colors of the rainbow. 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. 18

19 Visible Light Waves When white light shines through a prism, the white light is broken apart into the colors of the visible light spectrum. Water vapor in the atmosphere can also break apart wavelengths creating a rainbow. 19

20 Ultraviolet Light Waves Though these waves are invisible to the human eye, some insects, like bumblebees, can see them! 20

21 Ultraviolet Light Waves the ultraviolet part of the spectrum is divided into three regions: the near ultraviolet, (NUV) the far ultraviolet, (FUV) and the extreme ultraviolet (EUV). 21

Ultraviolet Light Waves Our Sun emits light at all the different wavelengths in electromagnetic spectrum, but it is ultraviolet waves that are

22 Ultraviolet Light Waves 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 Angstroms to be exact. 22

23 X Rays As the wavelengths of light decrease, they increase in energy. X-ray light tends to act more like a particle than a wave. X-ray detectors collect actual photons of X-ray light 23

24 X Rays X-rays were first observed and documented in 1895 by Wilhelm Conrad Roentgen. 24

25 X Rays Because your bones and teeth are dense and absorb more X-rays then your skin does, silhouettes of your bones or teeth are left on the X-ray film while your skin appears transparent. Metal absorbs even more X-rays 25

26 X Rays This is an X-ray photo of a one year old girl. 26

27 X Rays in Space This image of Comet Hyakutake was taken by an X-ray satellite called ROSAT, short for the Roentgen Satellite. (It was named after the discoverer of X-rays.) 27

28 The Sun also emits X-rays - here is what the Sun looked like in X-rays on April 27th, This image was taken by the Yokoh satellite. X Rays in Space 28

29 Gamma Waves 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 29

30 Gamma Waves In the late 1960s and early 1970s, detectors on board the Vela satellite series, originally military satellites, began to record bursts of gammarays -- not from Earth, but from deep space! 30

31 Polarized Light 31

32 Polarized Light Polarized by Transmission: 32

33 Polarized Light 33

34 Polarized Light Picket Fence Analogy 34

35 Polarized Light Polarized by Reflection 35

36 Polarized Light Polarization by Refraction 36

37 Polarized Light 3-D Movies Three-dimensional movies are actually two movies being shown at the same time through two projectors. The two movies are filmed from two slightly different camera locations. 37

38 3-D Movies The two movies are filmed from two slightly different camera locations. Each individual movie is then projected from different sides of the audience onto a metal screen. The movies are projected through a polarizing filter. There are two slightly different movies being projected onto a screen. Each movie is cast by light which is polarized with an orientation perpendicular to the other movie. The audience then wears glasses which have two Polaroid filters. Each filter has a different polarization axis - one is horizontal and the other is vertical. The result of this arrangement of projectors and filters is that the left eye sees the movie which is projected from the right projector while the right eye sees the movie which is projected from the left projector. This gives the viewer a perception of depth. 38

ELECTROMAGNETIC SPECTRUM All waves travel the SAME speed (the speed of light) 300,000 km/sec (186,000 miles/sec) in a vacuum

ELECTROMAGNETIC SPECTRUM All waves travel the SAME speed (the speed of light) 300,000 km/sec (186,000 miles/sec) in a vacuum 10 4 Hz 10 6 Hz 10 8 Hz 10 12 Hz 10 14 Hz 10 16 Hz 10 18 Hz 1 million 1 trillion