1. Light

2. Light – An Electromagnetic Wave
Light is a “wave”.
Light is special because light can travel through vacuum of outer space.

3. Light – An Electromagnetic wave
An electromagnetic wave: is a wave that has both electric and magnetic parts, does not require a medium, and travels at the speed of light

4. Electromagnetic spectrum
The term “Light” usually refers to the visible part of the electromagnetic spectrum.
Video – Electromagnetic Spectrum

5. Wavelength and Frequency
Wavelength – the distance between successive crests on a wave.
Frequency – the number of cycles a wave goes through in one second.

6. More on the EM Spectrum Longer Wavelength Shorter Wavelength
(Low Energy)
Shorter Wavelength
(High Energy)

7. Red Orange Yellow Green Blue Indigo Violet
White Visible Light
Continuous sequence of colors. Color sequence is called the visible spectrum
Red Orange Yellow Green Blue Indigo Violet
ROY-G-BIV

8. The Production of Light
Incandescence
Hot things glow

9. The Production of Light
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Electric discharge
Electric current passing through a gas

10. The Production of Light
Bioluminescence
Chemiluminescence in living organisms

11. The Production of Light
Phosphorescence and Fluorescence
Material absorbing U.V light
In phosphorescence, visible light is emitted over a period of time
In fluorescence, immediately
Phosphorescent powder under visible light, ultraviolet light, and total darkness

12. The Production of Light
                                                                                   
     
Phosphorescent powder under visible light, ultraviolet light, and total darkness.
Triboluminescence
- friction from scratching, crushing, or rubbing certain crystals

13. The Production of Light
Light-Emitting Diode (LED)
Electric current flowing in semiconductors