1. Sound

2. All sounds are produced by the vibrations of material objects They are compressional waves carried by a medium (air, water, solid) The molecules vibrate to the sound and transfer it to other molecules via collisions

3. Sound The frequency of a sound wave is described by its pitch. High pitch = high frequency, low pitch = low frequency Humans can hear between 20Hz to 20000Hz.

4. Sound The speed of a sound wave is mostly dependent on the density of materials Sound travels much faster in water than in air, and even faster through solids than water. Sound does not travel well through rubber.

5. Sound

6. Speed of Sound

10. Try these problems

11. Sound Natural Frequency – the frequency an object vibrates at which depends on factors like the objects shape and elasticity. Resonance – When the frequency of a forced vibration matches the natural frequency of an object, a dramatic increase in the amplitude of the vibration happens.

12. Sound Sound can also go through constructive and destructive interference Many NFL and NBA stadiums use acoustic technology to make their arenas louder by designing their buildings to magnify the sound made by fans Destructive sound interference is used in anti-noise technology. Noise canceling headphones have microchips that make sound that is out of phase with the loud noises, therefore canceling it.

13. Sound Video on resonance

14. Sound Pg 402 2, 6, 8, 13, 21, 22 EC: 35 We will learn about beats on Thursday