• anything moving back and forth is vibrating
• Wave is wiggle caused by a vibration/disturbance
  • Water wave
  • Pendulum
  • Light
  • Sound
  • etc.
• Pendulums swing back and forth, depends only on length
• Time back and forth is period (again Does not depend on mass)
• Waves
  • 
  • frequency == how often period in 1 second
  • hertz
  • frequency is inverse of period
  • 5hertz = 5 waves per second
• Wave speed
  • $$WaveSpeed = wavelength * frequency$$
• transverse waves
  • vibrating to right angles to direction of propagation
  • 
• longitudinal waves
  • is parallel to propagation/same direction
  • 
• Wave behaviors
  • Reflection
    • change of direction when bounced off barrier
  • refraction
    • Change of direction of wave
  • diffraction
    • change in direction as they pass a barrier
  • interference
    • 2 waves meet each other and interact
    • causes a net effect on the particles
    • Add/subtract the waves in a place
    • Standing waves are interference that pass through each other