Chapter 3 - Sound Flashcards
How is sound produced?
Sound waves are produced through vibrations in the air.
Let’s say you have a drum, the vibrating drum makes the air particles next to it vibrate. When then the air next to the drum vibrates, the air particles next to that will also vibrate. The sound wave moves through the air to your ear, the air itself does not travel away from the cone.
How can we use a slinky to represent a sound wave?
If you move a slinky’s ends, forwards and backwards, the coils move together and apart as the wave moves along, the individual coils does not travel to the end, but the wave does.
How do air particles in a sound wave act?
What happens to a slinky, also happens to air particles in a sound wave. Where air particles are close together it is called compression whereas in air particles that are far apart, it a called a rarefaction.
How does sound travel?
Sound waves need materials/medium to travel through such as air, water or solid. The vibrator sources produces a sound wave that makes in the medium vibrate backwards and forwards as the sound wave moves through, if this wave reaches your ear, you hear a sound.
In a vacuum, where there is no air, there are no particles to transfer the sound waves from the source to the detector, so there is no sound.
What are transverse waves?
Transverse waves are waves that can be made by moving a rope up and down. The particles move at right angles towards the direction of the wave. An example of this are Mexican or stadium waves.
What are longitudinal waves?
Longitudinal waves are waves that can be made on a slinky spring by moving your hand in and out. The coils of the slinky spring move to and fro in the same direction as the longitudinal wave is travelling. An example of this are sound waves and some types of earthquakes.
