Electromagnetic RadiationElectromagnetic Radiation

What is electromagnetic radiation ?What is electromagnetic radiation ?

Transverse waves that transfer energy by Transverse waves that transfer energy by radiationradiation

Examples: Gamma Rays, Visible Light, Examples: Gamma Rays, Visible Light, Infrared, Ultraviolet, Radio Waves, X-rays and Infrared, Ultraviolet, Radio Waves, X-rays and MicrowavesMicrowaves

How to Interpret the ElectroMagnetic Spectrum

As the wavelength increases the frequency decreases

Increased frequency means more energy

Radio WavesRadio WavesElectromagnetic radiation which has the lowest

frequency, the longest wavelength, and is produced by charged particles moving back and forth; the atmosphere of the Earth is ; the atmosphere of the Earth is transparent to radio waves with wavelengths transparent to radio waves with wavelengths from a few millimeters to about twenty meters. from a few millimeters to about twenty meters.

MicrowavesMicrowavesElectromagnetic radiation which has a longer

wavelength (between 1 mm and 30 cm) than visible light. Microwaves can be used to study the Universe, communicate with satellites in Earth orbit, and cook popcorn.

Infrared Infrared We often think of this as being the same We often think of this as being the same

thing as 'heat', because it makes our skin thing as 'heat', because it makes our skin feel warm. In space, IR light maps the feel warm. In space, IR light maps the dust between stars. between stars. http://gallery.spitzer.caltech.edu/Imagegallery/image.php?http://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=ssc2003-06v3image_name=ssc2003-06v3

Visible LightVisible LightElectromagnetic radiation at wavelengths which

the human eye can see. We perceive this . We perceive this radiation as colors ranging from red (longer radiation as colors ranging from red (longer wavelengths; ~ 700 nanometers) to violet wavelengths; ~ 700 nanometers) to violet (shorter wavelengths; ~400 nanometers.) (shorter wavelengths; ~400 nanometers.)

Why should you not buy red Why should you not buy red scuba equipment?scuba equipment?

Ultraviolet or UVUltraviolet or UV

Electromagnetic radiation at wavelengths shorter than the violet end of visible light; the ; the atmosphere of the Earth effectively blocks the atmosphere of the Earth effectively blocks the transmission of most ultraviolet light. transmission of most ultraviolet light.

No Tan Is A Good Tan!!!!No Tan Is A Good Tan!!!!

X-RayX-RayElectromagnetic radiation of very short

wavelength and very high-energy; X-rays have ; X-rays have shorter wavelengths than ultraviolet light but shorter wavelengths than ultraviolet light but longer wavelengths than gamma rays. longer wavelengths than gamma rays. http://chandra.harvard.edu/photo/2005/gctr_bin/bh_swarm_sm.movhttp://chandra.harvard.edu/photo/2005/gctr_bin/bh_swarm_sm.mov

Gamma RaysGamma RaysThe highest energy, shortest The highest energy, shortest wavelength

electromagnetic radiationselectromagnetic radiations. Usually, they are . Usually, they are thought of as any photons having energies thought of as any photons having energies greater than about 100 keV. (It's "gamma-ray" greater than about 100 keV. (It's "gamma-ray" when used as an adjective.) when used as an adjective.)