Helpmyphysics

Here is a simulation of a spring with a mass attached.
Press the play button to start.

The black car is moving towards an observer,represented by the green ball, while sounding its horn.
The sound waves spread out from the car. Notice that the sound waves squash up as the car approaches the observer and stretch out as the car leaves the observer behind.
Press the run button to start the program.
Can you see why the observer hears a higher frequency of sound as the car approaches and a lower frequency of sound as the car moves away?

The amount of scientific programmes on the BBC’s In Our Time hosted by Melvyn Bragg are fabulous.
This one is about the electron and is applicable to pupils studying Higher Physics or National 5.
Find the link below or click on the picture.

The Electron