2. SOUND NOTES SOUND NOTES (Click title to view video)

4. How does sound travel? Sound is a form of energy that moves in waves through matter. Sound waves are longitudinal waves or compressional waves.

5. Properties of Sound Waves Sound waves move out from a vibrating object in all directions. As a sound wave travels further from the object, the wave gets weaker.

6. How is sound produced? The movement of particles around a vibrating object creates a sound wave. – Your vocal cords vibrate air molecules. They vibrate other air molecules and so on until the air molecules by the listener’s ear vibrate their ear drum.

7. Speed of sound The speed of sound in air at room temperature is about 344 m/s. v Sound in Air = 344 m/s

8. Speed of Sound If the particles are closer together, they hit faster and the wave (sound) moves faster. Does sound move faster in: – air or water? – water or steel? Faster than the speed of sound.

9. When one particle bumps another that bumps another and so on, a sound is made. IS THERE SOUND IN SPACE?

10. LOUD and soft Sounds Intensity: strength of a sound – Which sound is more intense, an airplane or talking? – Which has more energy? Intensity is measured in Decibels. Your ear hears intensity as volume of a sound.

11. Intensity of a wave The intensity of a wave is shown by the amplitude. An intense sound is LOUD so it has a high amplitude. LOUDSOFT

12. and sounds The pitch describes high and low sounds. – A high sound like a flute has a high pitch. – A low sound like a tuba has a low pitch.

13. Pitch of a wave The pitch of a wave is shown by the frequency. A high pitch sound has a high frequency and a short wavelength.

15. ECHOS When sound waves reflect, they make an echo. Sonar uses echo to locate objects under water. Ultrasound uses echos to “see” inside the human body.

16. Doppler Effect Watch this segment from TeacherTube to learn more about the Doppler Effect.Doppler Effect