1. Sound
JC Physics

2. What is sound?

3. Sound is a form of energy

4. Vibrations
Sound is caused by vibrations.

5. Sound is produced when objects vibrate.

7. Vibrations are a form of kinetic energy
Vibrations are a form of kinetic energy. Sound is made by vibrations thus sound is a form of energy

8. Travels in Waves

9. Speed of sound in Air – 340 m/s

10. Needs a medium to travel

11. Some materials are better at carrying sound.
Generally denser materials carry sound vibrations faster because particles are closer together.
For example?

12. Light v Sound
Light travels nearly one million times faster than sound.

13. Speed of Light is?

14. The Ear
Outer ear collects the vibrations and directs them towards the eardrum.
Sound makes the eardrum vibrate and it passes these vibrations into the inner ear where nerves pick up the vibrations and send them as electrical signals to the brain.

17. Decibels
A Decibel is a measure of how loud a sound is.

20. Reflection
Echoes are reflected sound.

23. Speed = Distance ÷ Time
Distance
Time
SPEED

24. If the time-lag between seeing lightning and hearing thunder is 5 seconds, how far away is the storm?

25. When a girl was a certain distance from a high cliff she shouted loudly. One and a half seconds later the echo returned from the cliff. How far was the girl from the cliff?

26. Ultrasound
Can be used to scan inside the human body or to search the sea for fish.

28. How does it work?

29. Also used to find rocks etc

30. Animals also use Ultrasound....Sonar

31. And Dolphins

32. Questions! How is sound produced?
Draw a labelled diagram of an apparatus used to show that sound is a form of energy.
Draw a diagram and write a brief note to demonstrate that sound is caused by vibrations.
What is ultrasound?
What is the speed of sound in air?
Give two differences between sound and light waves.
Give two applications of reflected sound.

33. A guitar string is plucked. The sound is heard
A guitar string is plucked. The sound is heard. It seems simple, but there are a few stages in between. Can you put the following stages in the correct order?
vibrating eardrum, brain, vibrating source, vibrating air, nerve