Light Notes

Wavelength

A way of measuring a wave

why am i writing this down? i work with electronics/electricity already know this

Crest=top of wave

Trough=bottom of wave

Amplitide=from 0hz to the top of a wave (how tall a wave is)

Frequency=the speed of a wave - ex: a radio wave has a very low wavelength that can be as big as a building or a human

Microwave=a lower frequency thats about the length of a bug, used in microwaves

InfraRed=about the size of a pinhead, heat/remote control lights

Visible Spectrum=about the size of Protozoans

Ultraviolet Light=about the size of molecules

X-ray wavelength=About as long as atoms, making it able to get through some things other than something like bones

Gamma Wavelength=About the size of an atom nuclei

Radio Waves

Produced by feeding an electric signal to the mast or antenna of a transmitter

It has the longest wavelengths in the spectrum

These waves can be longer than a football field or as short as a football

Ray's TV reception uses radio waves

The satelite at Ray's TV - recieves movies via radio waves from a satelite

TAXI - driver recieves instructions on a CB radio which uses radio waves

Radio Tower - broadcasts radio signals

Large Satelite - dish in field - recieves radio waves from distant stars

Microwaves

Microwaves have wavelengths that can be measured in centimeters

The longer microwaves, those closer to a foot in length, are the waves we heat our food with in a microwave oven

They are good for transmitting information from one place to another because microwave energy can penetrate haze, light, rain and snow, clouds, and smoke

Shorter microwaves are used for radar and the doppler radar used in weather forcasts, Microwaves, used for radar, are just a few inches long.

Infrared waves

The longer, far infrared wavelengths are about the size of a pinhead and the shorter, near infrared ones are the size of cells, or are microscopic

The heat that we feel from sunlight, a fire, a radiator, or a warm sidewalk in infrared

Shorter wavelengths are the ones used by your TV's remote control

The Visible Spectrum

Cones in our eyes are receivers for these tiny visible light waves

The Sun is a natural source for visible light waves and our eyes see the refletion of this sunlight off the objects around us

The color of an object that we see is the color of light reflected. All other colors are absorbed

Water droplets cause the white light to break apart into seven colors. This is how rainbows work

Portrait photographers use film sensitive to visible light

Astronomers look at visible light from planets and stars

UltraViolet Waves

Astronomers have to put ultraviolet telescopes on satellites to measure the ultraviolet light from stars and galaxies - and even closer things like the Sun

A tanning booth uses ultraviolet waves to tan our skin

X-Ray waves

X-ray light tends to act more like a particle than a wave. X-ray detectors collect actual photons of X-ray light.

The Earth's atmosphere is thick enough that virtually no X-rays are able to penetrate from outer space all the way to the Earth's surface

X-ray telescopes and detectors are placed on satellites. We cannot do x-ray astronomy from the ground can not be done from Earth.

Comets emit x-rays

The Sun also emits X-rays

Many things in deep space give off x-rays

Gamma Rays

Gamma-rays are generated by radioactive atoms and in nuclear explosions

They can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells

Gamma-rays travel to us across vast distances of the universe

Instruments abord high-altitude balloons and satellites like the Compton Observatory provide our only view of the gamma-ray sky