1. Waves, Electromagnetic Spectrum & Color Theory
What is Light?

2. How is light generated?
What are some different ways light is generated?
Link to file
Incandescent, fluorescence, chemiluminescence (glowsticks), electric discharge (neon signs), LEDs, nuclear fusion (sun)…

3. Waves
A wave is a disturbance that transfers energy from one point to another without transferring matter.
Which way is this wave travelling?
Watch one particle of the wave. Which way is the particle travelling?
Does the particle move forward with the wave?

4. Parts of a Wave Wavelength Amplitude
Distance from crest to crest or from trough to trough
Amplitude
Height of wave from the rest position

5. Light is a Wave
Light is a form of energy known as electromagnetic radiation.
The light we can see, the visible spectrum, are only a small portion of the energy that surrounds us every day.
This is the visible spectrum. It is made of different colors. Can you think of a mnemonic to remember the order of colors?

9. Light is a Wave
Using a prism, white light can be separated into the different colors that make up the visible spectrum.
Each color has its own, unique wavelength.

10. Additive Color Theory
White light is made of different colors of light.
Additive color theory says that we can produce white light by combining different colors of light. Usually the additive “primary” colors red, green and blue are used.
Can you think of any applications of color theory?

11. Subtractive Color Theory
When light strikes an object, some wavelengths (colors) are reflected, and some are absorbed.
When you see a green apple, what wavelengths do you think are absorbed? Which are reflected?
What color light do red, blue and green light make?

12. Subtractive Color Theory
According to subtractive color theory, the colors that are absorbed by the object are “subtracted” from the reflected light seen by your eye.
Red objects reflect red light , and absorb all other colors
Black objects absorb all colors
White objects reflect all colors
White light
The subtractive “primaries” are cyan, magenta and yellow. They are opposite to the additive primaries.

13. Subtractive Color Theory
Can you think of any examples of subtractive color theory?

14. Color Theory Links Additive color theory: Link 1, Gizmo
Subtractive color theory: Link 1, Gizmo
Color filters: Link 1, Link 2

15. End Here!