Sound is a longitudinal wave that travels faster in denser and more elastic materials and at higher temperatures. It travels fastest in solids like the ground, slower in liquids like water, and slowest in gases like air. The frequency of a sound wave determines its pitch, with higher frequencies corresponding to higher pitches. When a sound source moves towards a listener, the sound waves are compressed, increasing the observed frequency and pitch via the Doppler effect.

1. Unit 31 – The Properties of Sound

3. Sound travels at different speeds in different materials and at different temperatures.

4. Sound will travel faster at higher temperatures than it will at lower temperatures.

6. Wave Speed Waves go faster based on the density of their medium because the tighter packed the molecules, the easier it is to transfer their energy to each other.

8. Larger vibrations make lower sounds and vice versa.

10. A.Freshwater at 0°C

11. B.Freshwater at 25°C

13. A.Freshwater at 0°C

14. B.Freshwater at 25°C

20. A. There is no change in the intensity.

21. B. There is no change in the frequency.

22. C. The frequency seems to decrease.

24. A. There is no change in the intensity.

25. B. There is no change in the frequency.

26. C. The frequency seems to decrease.