11 1 Sound travel How does sound travel

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11. 1 Sound travel How does sound travel? • Sound is made by vibrations.

11. 1 Sound travel How does sound travel? • Sound is made by vibrations. • It is heard by your ears and brain. • How does it get from a vibrating object to your ears? © Oxford University Press 2009

11. 1 Sound travel How does sound travel? • The vibrations from an object

11. 1 Sound travel How does sound travel? • The vibrations from an object set the particles in the air around it vibrating. • The vibrations move from particle to particle and the sound moves through the air. • Eventually it hits your ear. © Oxford University Press 2009

11. 1 Sound travel How does sound travel? • Sound moves through air particles

11. 1 Sound travel How does sound travel? • Sound moves through air particles in a very regular pattern of vibration. • It moves as a wave. © Oxford University Press 2009

11. 1 Sound travel Sound waves • A good model of how sound waves

11. 1 Sound travel Sound waves • A good model of how sound waves travel is a Slinky. • The video file shows the energy from a vibration moving as a wave through a Slinky. © Oxford University Press 2009

11. 1 Sound travel Sound waves • As the energy passes through the Slinky,

11. 1 Sound travel Sound waves • As the energy passes through the Slinky, it pushes (or compresses) the coils together. This is called compression. • The picture shows one wave following another through a Slinky: compression © Oxford University Press 2009

11. 1 Sound travel Sound waves • As the energy is transferred forward to

11. 1 Sound travel Sound waves • As the energy is transferred forward to the next coils, those are pushed together and the ones behind spread out (rarefaction). rarefaction compression © Oxford University Press 2009

11. 1 Sound travel Sound waves Watch the video again carefully to see what

11. 1 Sound travel Sound waves Watch the video again carefully to see what happens to the springs as the wave passes through. © Oxford University Press 2009

11. 1 Sound travel Sound waves • When the wave has passed through the

11. 1 Sound travel Sound waves • When the wave has passed through the Slinky, all the springs are in the same place as they were before. • A wave like this travels through a material like air, water or metal but the material itself stays where it is. © Oxford University Press 2009

11. 1 Sound travel Sound waves • This model in the animation shows how

11. 1 Sound travel Sound waves • This model in the animation shows how the vibrations from a tuning fork form waves through the air. © Oxford University Press 2009

11. 1 Sound travel Sound waves • Why doesn’t sound travel through a vacuum?

11. 1 Sound travel Sound waves • Why doesn’t sound travel through a vacuum? • Why does sound travel faster in liquids and solids than it does in air? © Oxford University Press 2009