1. Can You Hear It? (Almost) Everything You Need to Know About Sound

2.  Sound is the movement of air.  Sounds begin when something vibrates, or quickly moves back and forth.  For example, a guitar string begins vibrating and a sound is produced.  Another example- our vocal cords vibrate when we talk or sing.  Sound carries energy. This is why loud sounds hurt our ears.

3.  Sound travels in waves called sound waves.

4.  Sound travels through different materials at different speeds.  Sound travels through solids faster than liquids or gases.  Check out how fast sound travels through different materials: Air- 330 meters per second Water- 1,500 meters per second Wood- 4,000 meters per second Granite Rock- 6,000 meters per second

5. Sound goes through the ear canal, hits the eardrum and causes a vibration. The sound enters tubes in the inner ear. Then it travels through nerves to the brain.

6.  Each sound has a different wavelength. A wavelength is the distance from one area of squeezed particles to another.

7.  Every sound has a different frequency. Frequency is the number of times a sound source vibrates in one second.  Frequency determines pitch, or how high or low a sound is.  Fast vibration = high frequency = high pitch  Slow vibration = low frequency = low pitch

8.  Amplitude is the amount of energy in a sound wave.  High amplitude = high loudness or volume