Chp 12'112'2

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Chp 12.1-12.2

• Waves

2
Waves

• Waves are oscillations that carry energy and
  information from one place to another.
• Examples of waves light, sound, electricity in a
  wire, cell phone transmissions, ripple in a pond
• Two types of waves transverse and longitudinal

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Transverse Waves
transverse

• Transverse wave has its oscillations
  perpendicular to the direction of the wave. The
  wave moves left to right and the oscillation
  moves up and down
• Ocean waves are transverse waves

4
Longitudinal Wave
longitudinal

• Longitudinal wave has oscillations in the same
  direction the wave moves.
• Sound is a longitudinal wave

5
Frequency, amplitude, and wavelength parts to a
wave
Pitch

• Frequency of a wave is a measure of how often it
  goes up and down and is measured in hertz (Hz)
• Amplitude of a wave is the height of the wave
  above the level surface
• Wavelength is the length of one complete cycle of
  a wave. Typically measured from crest to crest
  or trough to trough

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Speed

• Speed describes how fast the wave moves
• Speed is frequency (f) times wavelength (l)

Speed (m/sec)
Wavelength (m)
Frequency (hz)
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What happens when a wave hits something?

• Reflection bounce off and goes in a new
  direction.
• Refraction bends as it crosses the edge

Ripple Tank
8

• Diffraction bends as it goes around a corner or
  through an opening
• Absorption amplitude gets smaller and smaller as
  it passes through the material