Interactions of Waves

Reflection Reflection – when a wave hits an object and bounces off of it. Reflection – when a wave hits an object and bounces off of it.

Refraction- is the bending of waves as they passes from one medium to another. * caused by a change in speed

Diffraction- when a wave hits an object and changes direction to bend around it. Diffraction- when a wave hits an object and changes direction to bend around it.

Interference – When two waves meet and form a new wave. Interference – When two waves meet and form a new wave. Constructive Interference – the combined waves have a higher amplitude than the original waves. Constructive Interference – the combined waves have a higher amplitude than the original waves. Destructive Interference - the combined waves have a smaller amplitude than the original waves. Destructive Interference - the combined waves have a smaller amplitude than the original waves. Waves are very chaotic or can cancel out. Waves are very chaotic or can cancel out.

Standing Waves Standing Waves – the combining of waves that makes them appear to stand still. Guitar strings, musical instruments Guitar strings, musical instruments Node – Points on the wave that don’t move (rest position). Node – Points on the wave that don’t move (rest position). It is the point where Constructive and Destructive Interference meet and cause an amplitude of zero on the standing wave. It is the point where Constructive and Destructive Interference meet and cause an amplitude of zero on the standing wave. Antinode – Areas on the wave with the greatest amplitude (crest and trough) Antinode – Areas on the wave with the greatest amplitude (crest and trough) the point where Constructive and Destructive Interference meet and form the maximum amplitude. the point where Constructive and Destructive Interference meet and form the maximum amplitude.

Seismic Waves Seismic Waves – waves of energy that travel through the Earth’s crust Seismic Waves – waves of energy that travel through the Earth’s crust P - primary waves (pressure) P - primary waves (pressure) S - secondary waves (transverse) S - secondary waves (transverse) L - surface waves (1 0 and 2 combo) L - surface waves (1 0 and 2 combo)

P Waves P waves –- Primary waves are pressure waves & are the fastest moving waves, they travel thru solids and liquids, Push- Pull Waves AKA Longitudinal waves P waves –- Primary waves are pressure waves & are the fastest moving waves, they travel thru solids and liquids, Push- Pull Waves AKA Longitudinal waves

S Waves S Waves – Secondary Waves are slower than primary waves, they cannot travel thru liquid and are Transverse Waves. S Waves – Secondary Waves are slower than primary waves, they cannot travel thru liquid and are Transverse Waves.

L Waves L Waves (last waves) Surface wave – the combination on the Earth’s surface of Primary and Secondary waves. L Waves (last waves) Surface wave – the combination on the Earth’s surface of Primary and Secondary waves. The rolling chaotic movement of the surface The rolling chaotic movement of the surface Cause the most damage of the seismic waves Cause the most damage of the seismic waves