1. Sound Unit

2. 1. Vibration – a rapid back and forth movement that produces sound.

3. 2. 3 ways sound is similar to light: 1) Travels outward in all directions. 2) Travels in waves. 3) A form of energy.

4. 3. Compression – region of a sound wave where molecules are crowded together.

5. 4. Rarefaction – region of a sound wave where molecules are spread apart.

6. 5. 3 characteristics that describe a sound wave are: 1) Wavelength 2) Frequency 3) Amplitude

7. 6. Amplitude – height of the wave.

8. 7. Pitch – how high or low a sound seems. Pitch depends on the frequency of waves. Long waves produce low frequencies. Short waves produce high frequencies.

9. 8. Frequency of sound is measured in units called hertz (Hz).

10. 9. Intensity – amount of energy a sound has (loudness). Soft Sound Loud Sound

11. 10. Intensity or loudness of sounds is measured in units called decibels (dB).

12. 11. 3 things can happen when sound strikes matter. Transmit – travels through the material. Absorb – trapped in material. Reflect – bounces off the material.

13. 12. Sound travels 0.2 miles per second.

14. 13. Molecules look differently depending on the type of matter they are in. GasLiquid Solid

15. 14. Speed of sound through materials from fastest to slowest: Solid Liquid Gas

16. 15. Echolocation – using reflected sound to locate objects.

17. 16. Infrasonic Sound – sound with a frequency below 20 Hz.

18. 17. Ultrasonic Sound – sound with a frequency above 20,000 HZ.

19. 18. Sonogram – made when sound waves are reflected off parts of a human’s body.

20. 19. Sonar – method of using ultrasonic sound to locate objects under water.

21. List as many things that you know about sound so far from our unit of study.

22. Which wave shows a low- pitched, soft sound?

23. Which wave shows a high- pitched, loud sound?

24. Which wave shows a high- pitched, soft sound?

25. How are frequency of a wave and pitch related? How do they go hand-in-hand?

26. 19. Sonar – method of using ultrasonic sound to locate objects under water.