Interference of Waves

What happens when two waves meet? Okay, how did these two waves meet? Did they meet on eHarmony?? Ha,Ha,Ha Now I am serious… Does the wave get bigger? Does it get smaller?

Observe and see while I demonstrate with the wave machine.

Let’s Discuss:

What did you observe? Two crests going in the opposite

direction will _________________ when they meet.

A crest and a trough moving in the opposite direction will ___________ when they meet.

What happens after they meet? What did you see???

Interference

When two or more waves meet, a new wave is made

This is known as interference

Principle of Superposition

This principle states at any point, the amplitude of the two interfering waves is the sum of the amplitudes of the individual waves

Constructive interference: two or more waves create a larger amplitude

Destructive interference: two or more waves create a smaller amplitude

Look at the diagram below:

What would the resultant wave look like???

Technology Using Interference Waves Noise cancelling headphones use the

concept of destructive interference. The electronics inside the headphones generate a wave that is out of phase with sound waves in the exterior environment.

This out of phase wave is played inside the headset

Using destructive interference the outside noise is cancelled, allowing the listener to play music at lower volumes.

Your Turn…

You will be getting a handout. Please complete. Once you have finished the first handout

( both sides), you will be getting another handout or lets say a “package”.

The second handout or ‘package’ is also to be completed.

Enjoy