Wave Behavior

1
Wave Behavior

• Up to this point we discussed waves continuing on
  forever.
• Is this reality? Discuss with your elbow partner.
  
• Support your claim and give examples to support
  your claim.

2
Wave Behavior

• Waves will eventually reach the end of a medium
  or encounter an obstacle.
• The point where the mediums change is called the
  boundary.
• Behavior of a wave when reaching the end of a
  medium is called boundary behavior.

3
Wave Behavior

• When a wave encounters a boundary between two
  mediums (such as air and water), three things are
  possible
• Reflected
• Refracted
• Diffracted

4
Reflection
the turning back (bouncing off) of a wave When
it reaches the boundary of the medium through
which it is traveling

• A wave bounces off the new medium
• Examples
• Mirror (light)
• Echo (sound)

5
Refraction

• Occurs when a wave is transmitted into a new
  medium at an angle
• Bending of a wave when it passes into a new
  medium
• Occurs because the speed in one medium is
  different than the speed in a second medium

6
Diffraction
the spreading of a wave around a barrier
or through an opening
7
With your elbow partner discuss the following
question

• What do you think will happen when two different
  waves meet each other (interact)?
• Is there any information you wish you would have
  had access to before answering the question?

8
Interference
the result of the superposition of two or more
waves
Superposition Principle
the displacement of the medium when two or more
waves pass through it at the same time is the
algebraic sum of the displacements caused by the
individual waves
9
Wave Interference

• When two waves pass each other their
  superposition
• causes reinforcement or cancellation.

10
Types of Interference
Constructive results in a larger amplitude
Destructive results in a smaller amplitude
11
Constructive interference

• Reinforcement when the crest of one wave overlaps
  the crest of another
• Their individual effects adds together, resulting
  in a wave increased in amplitude

12
Destructive Interference

• Cancellation when crest of one wave overlaps
  trough of another reducing their individual
  effects
• Water waves show these best Out of phase- the
  crest of one wave arrives at a point at the same
  time as a trough of the second wave arrives,
  effects cancel each other In phase- two waves
  crests and troughs arrive at a place at the same
  time, effects reinforce each other