1. The Electromagnetic Spectrum
Different wavelengths of EM waves.
These wavelengths of light and others make up a spectrum.
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On the Spectrum…
Left Side
Right Side
Type of Wave
Wavelength
Frequency
Energy
Radio
Gamma
Long
Short
Low
High
Low
High
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3. VISIBLE LIGHT Electromagnetic waves we can see.
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Visible Spectrum
The visible spectrum contains seven colors.
Each of these colors corresponds with a particular wavelength.
Longest wavelength= red light
Shortest wavelength= violet (purple) light
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5. How can I remember the seven colors of the visible spectrum?
ROY G BIV
RANGE
REEN
LUE
NDIGO
IOLET ED
ELLOW
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White Light
White light is not a single color; it is made up of a mixture of the seven colors of the rainbow.
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Colour
We can demonstrate this by splitting white light with a prism:
This is how rainbows are formed: sunlight is “split up” by raindrops.
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Why do we see color?
When our eyes see different wavelengths of light in the visible spectrum, we see colors.
Light Wavelengths
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9. How do humans see color? Seeing colour Homework
What we actually see is the light an object reflects or in some cases the light an object produces.
For example, a red book only reflects red light:
Homework
White
light
Only red light is reflected
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A red stoplight appears green because it produces red light.
It’s LUMINOUS!
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11. The colors that don’t get reflected, are absorbed.
Seeing colour
The colors that don’t get reflected, are absorbed.
Absorption – the disappearance of an electromagnetic wave into a medium.
It’s the opposite of reflection!
It absorbs all the other colors. (OYGBIV)
Homework
White
light
Only red light is reflected
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12. A white hat would reflect all seven colors:
A pair of purple pants would reflect purple light
(and red and blue, as purple is made up of red and blue):
Purple light
A white hat would reflect all seven colors:
White
light
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Using coloured light
What about an outfit?
Shirt looks red
White
light
Shorts look blue
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Sun’s Rays (White Light)
Green Wavelength of light
Absorbs all other colors
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15. Black
When you see black, all of the wavelengths of light are absorbed and no light is reflected back at you.
Nothing is reflected.
All visible light is absorbed.
White
light
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16. Moving on to the HUMAN EYE
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