2. What is Sound? Chapter 12 Lesson 1 Pages 406-413

3. Our Goals… Explain what makes sound. Describe how sound varies in pitch and intensity. Identify how the intensity of sound is measured.

4. Sources of Sound Vibration- a quick back-and-forth movement As things vibrate, the air around it vibrates… these vibrations move through the air and we hear them as sounds. Vibrations can move through gases (air), solids, and liquids. Sound waves travel in all directions. The vibrations that cause sound are called sound waves. Sound waves travel in all directions. Sound waves make parts inside your ear vibrate and then a signal travels to your brain, and you hear the sound!

5. Pitch Pitch is how high or low a sound is. Smaller objects usually vibrate faster than large ones, giving a higher pitch. Big objects vibrate more slowly, producing a lower pitch. Faster vibrating objects produce sound waves that are closer together… slower vibrating objects produce sound waves that are more spread out.

6. Intensity Intensity is the measure of how loud or soft a sound is. Sound waves have a certain amount of energy… a heavier object would have more energy, so it would produce sound waves with more energy… thus, producing a louder sound.

7. Measuring Sound Intensity Sound intensity is measured by using a unit called a bel… named after Alexander Graham Bell. For most sounds, the bel is too big a unit to be used, so most sounds are measured in decibels. A dB is one-tenth of a bel.

8. (dB) 100 90 80 70 60 50 40 30 20 10 0 Threshold of hearing Rustling of leaves Quiet restaurant Highway traffic Jet aircraft at 300 m altitude

9. Rally Robin!! You will mix and then partner up to trade information you learned in this lesson. The person with the shortest hair will go first.

10. Quietly take out your remotes

11. A quick back-and-forth motion A.Pitch B.Vibration C.Decibel D.Intensity

12. How high or low a sound is A.Pitch B.Vibration C.Decibel D.Intensity

13. How loud or soft a sound is A.Pitch B.Vibration C.Decibel D.Intensity

14. The unit used to measure the loudness of sounds A.Pitch B.Vibration C.Decibel D.Intensity

15. Vibrations cause sound. A.True B.False

16. Sound can only travel through air. A.True B.False

17. Which dog produces a higher pitch? A. B.

18. Which book would have a higher intensity when dropped on the floor? A. B.

19. The bel was named after Thomas Edison. A.True B.False

20. Sound waves travel in one direction. A.True B.False