Presentation on theme: " A difficult question, thousands of years in understanding. Very difficult to study, since it cannot be caught, and it is very difficult to measure."— Presentation transcript:
A difficult question, thousands of years in understanding. Very difficult to study, since it cannot be caught, and it is very difficult to measure.
Light is a wave that travels through the universe’s electromagnetic field. Electromagnetism = a combination of electricity and magnetism Light waves do not need a physical medium like air.
Frequency – light is caused by the vibrations of electrons Wavelength – light waves have crests and troughs, just like water waves Speed – the speed of light depends on what it is traveling through.
299, 792, 485 m/s ≈ 3 x 10 8 m/s 186,282 miles per second 671 million miles per hour Can be slowed if passing through water, glass, etc.
Most light is invisible, because it has frequencies that our eyes cannot see. Light with faster frequencies has shorter wavelengths and higher energy Speed = wavelength x frequency Wavelength = 3 x 10 8 m/s ÷ frequency
Type Ballpark Frequency Ballpark Wavelength Radio (AM)10 6 Hz300 minvisible Radio (FM)10 8 Hz3 minvisible Microwaves & Radar 10 10 Hz3 cminvisible Infrared10 13 Hz.03 mminvisible
Type Ballpark Frequency Ballpark Wavelength Visible4.4 x 10 14 Hz700 nmRed 4.9 x 10 14 Hz600 nmOrange 5.1 x 10 14 Hz580 nmYellow 5.8 x 10 14 Hz530 nmGreen 6.3 x 10 14 Hz470 nmBlue 6.9 x 10 14 Hz430 nmIndigo 7.4 x 10 14 Hz390 nmViolet
Type Ballpark Frequency Ballpark Wavelength Ultraviolet10 16 Hz3 x 10 -8 minvisible X-Rays10 17 Hz3 x 10 -9 minvisible Gamma Rays (from space) 10 18 Hz3 x 10 -10 minvisible ???More?Smaller?invisible
Light is a wave. Light has frequency and wavelength. The speed of light in a vacuum is 3 x 10 8 m/s. It is the second fastest thing in the universe (only bad news travels faster).
There are many types of light, which all differ only by frequency/wavelength Faster frequency = shorter wavelength = more energy In order: Radio, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays, Gamma Rays
Light reflects (bounces off of objects), like on a mirror Light refracts (bends while passing through objects), like through a glass Light diffracts (spreads out and separates by wavelength), like making a rainbow