15.2

 Electromagnetic waves need no medium, are produced by moving electrons in a field.  Can be reflected, refracted, diffracted, produce standing waves

 Tiny bundles of energy that produce light.  They increase as frequency increases and wavelengths decrease

Sound and Light 4 Absorbs Energy

 Light is the fastest wave in the universe  Speed of light is 300 million m/sec- it takes 8 minutes from sun to earth

 Affected by the material that it passes through  Transparent- air, water, glass  Translucent- frosted glass diffuses light  Opaque-light can’t pass through.

 If light travels through an object it is =transparent  If light is blocked by an object and a dark shadow is cast it is= opaque.  If some light passes through but not all and a light shadow is present it is=translucent. *AIMS:Primarily Physics: Just Passing Through Activity

 Quantity of amount of light illuminating a surface, dependant on amount of light.  Decreases with distance

Sound and Light 10

 Describes physical waves using amplitude, wavelength and frequency.  Arranged by Frequency and wavelength

 Left side of spectrum has low frequency and large wavelengths, right side has high frequency and close wavelengths

 You begin with radio wave, microwaves, infrared, visible light, ultraviolet, x-rays and gamma

 Radio- lowest frequency, longest wavelength. Includes AM/FM and radar  Radar- Radio Detecting and Ranging

 Radar uses short radio impulses to locate and monitor speed once the signal is reflected back.  Microwaves follow radio waves and are used in cooking/communication

 Infrared- slightly lower wavelength than visible light  Felt has heat like in the sun and warming lamps

 Visible light – color spectrum  ROY G BIV  Red, orange, yellow, green, blue, indigo,violet

 The colors are ordered by wavelength.  50% of the sun’s light is visible

 Ultraviolet- higher frequency than visible light  Kills bacteria, causes cancer, produces vitamin D

 X-rays- frequency above ultraviolet waves, passes trough skin but is absorbed by bone, Lead can absorb all X-rays

 Gamma rays- has highest frequency and shortest wavelength, has highest energy and can penetrate 3 meters of concrete.