Waves, Light, Sound and Color

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Waves, Light, Sound and Color
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Waves

• Transfer energy through matter or space

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Waves

• May be longitudinal
• Or transverse

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Waves
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Waves travel through a medium such as
water
air
solids
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Wave Properties
reflection
refraction
interference
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Wave Properties

• Diffraction the bending of a wave around the
  edge of a barrier.

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Reflection, refraction, diffraction and
interference
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Sound waves

• Longitudinal waves
• Need a medium to travel through
• Speed of sound is 340 m/s in air

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Water waves
Water waves have transverse and longitudinal
characteristics. Energy is transferred, but the
particles stay essentially in the same place
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Light particle or wave?
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Particle or wave?
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Light particles are called photons
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Light Particle or wave?

• BOTH!!
• Light does not need a medium to travel through.

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Doppler effect

• Change in frequency and pitch of a sound.
• Due to the motion of either the sound source or
  the observer.
• Listen!

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Doppler effect of sound
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Doppler effect in light

• As stars move away from earth, there is a shift
  in the light towards the red end of the spectrum.

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Color
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Color

• When light strikes a surface, it can be
  transmitted, absorbed, or reflected

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Transmission of light

• When light is transmitted, a substance is said to
  be transparent.
• The color that is transmitted is the color that
  reaches your eye.

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Transparent objects transmit color

• Red glass absorbs all colors of light except red,
  which it transmits.

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Absorption of light
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Reflection and absorption of light

• Opaque objects reflect and absorb light.
• The color of an opaque object is the color it
  reflects.

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Opaque objects reflect and absorb light

• This apple reflects red and absorbs all other
  colors.

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Translucent objects transmit some light
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Color

• Primary colors are red, green and blue.
• Primary colors may be combined to make white
  light.

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Complimentary colors

• 2 colors that combine to form white light.

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Primary colors of light together form white
light. But primary pigments together make
black. This is because they absorb all colors.
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Bye-bye!