12/11/08
Post date: Dec 11, 2008 1:42:53 AM
Bell Activity: Reassemble your lab station and continue your observations. Have Mr. B check your observations when you finish.
Finish wave table lab
Wave behaviors
Superposition of waves (click the image below to see the animation)
When multiple waves occupy the same space, the result is the sum of the individual waves
The result of the superposition of two or more waves is called interference
Constructive interference - wave displacements are in the same direction, leading to a larger wave than either of the component waves
Destructive interference - wave displacements are in opposite directions, leading to a smaller wave than the bigger of the two component waves
Total destructive interference - wave displacements are in opposite directions with equal magnitudes, leading to a resultant displacement of zero ... the two waves cancel each other out completely at that moment!
Used in noise-canceling headphones to cancel out the sounds coming from outside the headphones
Standing waves
Interference that creates points which never move, so that a wave seems not to travel down the medium
Node - point along the medium that does not move from equilibrium
Antinode - point along the medium that moves the most
Reflection of Waves
Waves reflect off a barrier at the same angle as they enter
Angle of incidence - Angle they hit barrier at with respect to the normal
Angle of reflection - Angle they leave barrier at with respect to the normal
Law of reflection: Angle of incidence has same measure as Angle of reflection
Same law applies to shots in pool when you hit the wall: the ball hits at the same angle as it leaves the wall