# Light and Color for the Middle School by LoRnJMp

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```									Light and Color for the Middle
School
By Greg Corder
TOC
1.   Reflection and mirrors
2.   Refraction and lenses
3.   Applications of lenses and mirrors
4.   Color: light, pigments, and wavelength
5.   Diffraction
6.   Interference
7.   Light the electromagnetic wave
8.   Photoelectric effect
9.   Nature of light: particle, wave, or both?
The Law of Reflection
Flat surfaces
reflect best.
Curved Mirrors

• Concave mirrors converge light.

• Convex mirrors diverge light.
Concave Mirror
Light converges. This means that it comes together.
Also, the image is flipped past the focal point.
Convex Mirrors
Light diverges. This means that light spreads
out.
Curved Lenses

• Convex lenses converge light. The image is
flipped past the focal point.

• Concave lenses diverge light.
Refractions causes
light to bend.

The shape of the lens
determines how the
light behaves.
Applications of lenses and mirrors
Periscope
Color
Dispersion…
Color separates using a prism because different
colors have different wavelengths.

Red light bends the least and purple light bends
the most.
Color depends on Wavelength of Light.
Colored lights combine to appear
white.
Colored lights add to become white.
to become black?
Pigments are chemicals which are
capable of absorbing one
or more frequency of white light.
Behaviors of light
Diffraction – a wave bends around an object
Light is a wave!
Light
through a
small slit.
Interference: light is a wave!
Polarized
light is a
wave!
The Electromagnetic Spectrum

•

Maxwell - (c. 1864) light is an EM wave
The photoelectric effect: light is a particle!

The puzzle of intensity vs. energy
Einstein - (1905)
– The duality theory of light
– Light has a dual nature: light is both a
particle and wave
Sources:
http://www.glenbrook.k12.il.us/gbssci/phys/Class/BBoard.html
http://www.mhhe.com/tillery
Tillery, Physical Science.
http://cougar.slvhs.slv.k12.ca.us/~pboomer/physicslectures/seco
ndsemester/telescopes/refracting.jpg

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