K-12 Science, CCSD, 2006
Light
Photos, sounds, and clipart were inserted from Microsoft’s Office products unless noted.
K-12 Science, CCSD, 2006
Light Waves
• Light is another kind of energy that moves in waves.
• Write down 6 words to describe light.
K-12 Science, CCSD, 2006
Light Waves
• Light is another kind of energy that moves in waves.
• Light waves do not need a medium. They can travel through nothing!
K-12 Science, CCSD, 2006
Light Waves
• Light waves can be reflected.
• Light waves can be refracted (bent).
• Light waves can be absorbed.
K-12 Science, CCSD, 2006
Light Wavelength
• Just like sound, light has different wavelengths.
• Review the parts of a wave:
K-12 Science, CCSD, 2006
Parts of a Wave
A = Crest
B = Trough
D = one full wave
= one wavelength
= one period
C = AmplitudeCA
B
D
K-12 Science, CCSD, 2006
Light Wavelengths
• Light has different wavelengths.Red light has a large wavelength.
Blue light has a shorter wavelength.
K-12 Science, CCSD, 2006
Light Wavelengths
Red light has a large wavelength.
Blue light has a shorter wavelength.
• Would it take longer for a red light wave or a blue light wave to go past a point?
K-12 Science, CCSD, 2006
FrequencyRed light has a large wavelength.
Blue light has a shorter wavelength.
• The shorter, blue wavelengths would go past quicker.
K-12 Science, CCSD, 2006
Frequency
Large wavelength = low frequency
Medium wavelength = medium frequency
Small wavelength = high frequency
K-12 Science, CCSD, 2006
Frequency
• Don’t confuse the frequency with the speed of a wave.
• Here’s an analogy:
K-12 Science, CCSD, 2006
FrequencyIf you were looking down on a freeway . . .
And all of the vehicles were going exactly 60 miles per hour (the same speed). . .
K-12 Science, CCSD, 2006
Frequency Speed = 60 miles per hour
Small cars = high frequency (6)
Bus = low frequency (1)
K-12 Science, CCSD, 2006
Frequency Light speed = 186,000 miles per second
Blue light waves = higher frequency
Red light waves = lower frequency
K-12 Science, CCSD, 2006
Frequency – Visible Light
Red light
Orange light
Yellow light
Green light
Blue light
Violet light
K-12 Science, CCSD, 2006
Frequency – Visible Light
Red light
Orange light
Yellow light
Green light
Blue light
Violet light
K-12 Science, CCSD, 2006
Frequency – Visible Light
The light we use to see has all of these wavelengths in it.
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
Let’s start with our eyes.
To Brain
Light waves
Light waves
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
If there is no light . . .
To Brain
Light waves
Light waves
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
If there is no light . . .
To Brain
you cannot see because there are no
light waves reflecting to your eye.Our eyes only see light reflected off things!
K-12 Science, CCSD, 2006
So . . . How Do We See Colors?
The green part absorbs all of the colors except green. It reflects green light.
To Brain
The red part absorbs all of the colors except red. It
reflects red light.
Top Related