Wave Interactions

Reflection The interaction of a wave with a

surface it cannot pass through.Causes the wave to bounce back.

Ex: Looking in a mirror – light Ex: Echo – sound

Law of reflection – The angle the wave comes in at (incidence) = the angle the wave will be reflected at.

- Interactions of Waves

Refraction

Refraction The bending of waves. Due to a change in speed. Occurs when:

Enters a new medium

Enters it at an angleAND

One side of the wave enters first and changes speed first, causing the wave to bend.

Diffraction

When a wave moves around a barrier

When a wave moves through a hole or opening in a barrier.

OR

- Interactions of Waves

Diffraction

Interference Interaction between waves that

meet (run into each other) 2 types

Constructive (build up)Destructive (tear down)

- Interactions of Waves

Constructive Interference

When waves combine to make a wave with a larger amplitude.

When crest meets crest or trough meets trough.

Add their energies

• The interference that occurs when waves combine to make a wave with a smaller amplitude.

• Subtract their energies

Destructive Interference

Standing Waves A wave that appears to stand

still in one place. Actually 2 waves interfering

as they pass through each other.When an incoming wave

meets a reflected wave at just the right frequency.

Standing waves cont. Node: Point of zero amplitude

on a standing wave.Min. energy

Antinode: Point of maximum amplitude on a standing wave.Max. energy

Resonance When external vibrations

match an objects natural frequency

Increases the amplitude of the vibration