Electromagnetic Spectrum

Electromagnetic Spectrum • Visible light and color • Energy, frequency, wavelength • Real-world uses • Astronomy uses

http://www.lcse.umn.edu/specs/labs/images/spectrum.gif

http://cache.eb.com/eb/image?id=73584&rendTypeId=35

http://upload.wikimedia.org/wikipedia/commons/9/99/EM_Spectrum3-new.jpghttp://upload.wikimedia.org/wikipedia/commons/9/99/EM_Spectrum3-new.jpg

http://upload.wikimedia.org/wikipedia/en/thumb/8/8a/Electromagnetic-Spectrum.png/350px-Electromagnetic-Spectrum.pnghttp://upload.wikimedia.org/wikipedia/en/thumb/8/8a/Electromagnetic-Spectrum.png/350px-Electromagnetic-Spectrum.png

Visible light and color • A small part of the total spectrum • Approximately 400-700nm (4000-7000Å) • 700-650nm: Red • 650-600nm: Orange • 600-550nm: Yellow • 550-500nm: Green • 500-450nm: Blue • 450-400nm: Violet

http://solarsystem.nasa.gov/deepimpact/images/Spect-Prism-sm.jpghttp://solarsystem.nasa.gov/deepimpact/images/Spect-Prism-sm.jpg

http://wfc3.gsfc.nasa.gov/MARCONI/images-basic/spectrum.jpg

http://www.windows.ucar.edu/physical_science/magnetism/images/visible_spectrum_waves_big.jpghttp://www.windows.ucar.edu/physical_science/magnetism/images/visible_spectrum_waves_big.jpg Violet

http://www.yorku.ca/eye/spectrum.gif

http://saturn.jpl.nasa.gov/mission/images/EM-spectrum.jpg

-ray (gamma) • Very high energy • Very high frequency (big numbers) • Very short wavelengths (small numbers) • Emitted by radioactive sources • Astronomy: high energy processes, hot environments; colliding stars, around black holes, gas around galaxies

http://today.slac.stanford.edu/images/2007/swift-gamma-ray-lg.jpghttp://today.slac.stanford.edu/images/2007/swift-gamma-ray-lg.jpg

X-ray • High energy • High frequency • Short wavelengths • Used to determine whether bones are broken, and teeth have cavities • Astronomy: similar to -ray, plus the Sun

http://www.atnf.csiro.au/people/mdahlem/img/xmmtel.gif

Ultraviolet (UV) • Slightly higher frequencies and shorter wavelengths than humans can see • Some birds and insects can see in the UV • UV light causes suntans, sunburn, cancer, can be used to sterilize equipment • Astronomy: Used to study the Sun and other hot objects

http://sohowww.nascom.nasa.gov/data/realtime/eit_195/1024/latest.htmlhttp://sohowww.nascom.nasa.gov/data/realtime/eit_195/1024/latest.html

Visible Light • Approximately 400-700nm (4000-7000Å)

Infrared • Slightly longer wavelength and lower frequency than the human eye can see. • Some animals including some snakes, some bats, and some insects can see IR. • IR goggles help firefighters, soldiers, and home insulation experts; remote controls use IR • Astronomy: IR travels through dust so is good to look at young forming stars. (Spitzer Space Telescope)

http://upload.wikimedia.org/wikipedia/en/c/cf/Ir_girl.png

http://www.spitzer.caltech.edu/

http://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=ssc2007-19ahttp://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=ssc2007-19a

Microwave/Sub-mm • Low energy • Low frequency (small numbers) • Long wavelength (large numbers) • Used in microwave ovens, cellphone signals • Astronomy: cooler objects such as clouds of dust, and the Cosmic Microwave Background (light from the Big Bang)

http://apod.nasa.gov/apod/image/0302/sky_wmap_big.jpg

Radio • Very low energy • Very low frequency • Very long wavelengths • Radio transmissions for music, TV, walky-talkies, GPS, communicate with satellites, weather radar, radar guns • Astronomy: cool objects such as gas clouds, entire galaxies, SETI (potential alien communications)

http://cache.eb.com/eb/image?id=96170&rendTypeId=4

Nancay Radio Telescope

http://www.astro.utu.fi/~cflynn/astroII/crab.gif

http://www.thunderbolts.info/tpod/2006/image06/060123nebula.jpghttp://www.thunderbolts.info/tpod/2006/image06/060123nebula.jpg

http://www.andor.com/image_lib/lores/introduction/introduction%20(light)/intlight%201%20small.jpghttp://www.andor.com/image_lib/lores/introduction/introduction%20(light)/intlight%201%20small.jpg

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Electromagnetic Spectrum