Standard: Identify the characteristics of electromagnetic and mechanical waves

A. Produced by the motion of electrically charged particles moving back and forth.

A.The charged particles are surrounded by: i.Electric fields ii.Magnetic fields

B.Transverse waves C. Do not require a medium

d. All electromagnetic waves travel at 300,000,000 m/s in a vacuum Nothing travels faster than the speed of light!

e. Travels slower when passing through a medium

A.Particle nature i.Travels in bundles of energy ii.Bundles act like small particles iii.Called photons

A.Wave nature i.All electromagnetic waves travel at the same speed ii.Frequency and wavelength are used to classify the waves in the electromagnetic spectrum

The electromagnetic spectrum is the complete range of electromagnetic waves placed in order of increasing frequency.

Create your own Mnemonic device to remember the Waves of the EM Spectrum Radio Microwave Infrared Visible Light Ultraviolet X-rays Gamma Rays

Rotten Milk Is Very Undrinkable; X-tinguishes Gas

As the frequency increases: a.Wavelength decreases b.Photon penetrating energy increases

A.Uses: Communication (telephones,, radio transmission, global positioning system (GPS) B.Long wavelength and Low frequency C.Lowest Photon energy

A.Uses: Cooking, cellular phones, radar B.Long wavelength and Low frequency C.Lower Photon energy

A.Wavelength is only a little longer than visible light B.Uses – Remote controls, thermal energy transfer (radiant energy) including night vision, infrared photography, locating tumors (Remember all living object give off infrared radiation.)

A.Only wavelengths that can be detected by the human eye B.Use – allow humans to see

A.Higher frequency and shorter wavelength than visible radiation B.Uses– Produces vitamin D in human skin and can be used to kill bacteria and viruses (sterilize equipment) C.Warning! – too much can cause skin cancer; Ozone in the atmosphere blocks it

A.Higher frequency and photon energy – greater penetrating power B.Uses: X-ray pictures; rays will penetrate soft matter like skin and muscle, but it is absorbed by the harder bones

A.Highest frequency -- greater penetrating power B.Uses: destroy human cells and can be used to kill cancerous cells