Sounds

Sounds

1. Sounds waves

   • Sounds travel through the air as waves, Sound waves are made by vibrations pushing the air to and fro.

2. Sounsd travel

   • Sound waves travel through solid ans liquids. The particles in solids and liquids are much closer together than the particles in gases, so they pass on sound vibrations more quickly.
     • Space is a vacuum there is no air. Sound waves can only travel where there are solids, liquids or gases to carry them.

3. Musical instruments

   • Strings
     • String instruments, have stretched strings that vibrate when they are plucked. By changing the length or tension can play many different notes.
   • Wind
     • Wind instruments, air vibrate when the musician blows into the tube. The player changes the pitch of the note by opening holes in the side of the tube to change the length of the vibrating air.
   • Percussion
     • Percussion as drums, triangles and cymbals, vibrate when they are hit or tapped.
   • Musical instruments use vibrations to make sounds. Changes the speed play notes of different pitch.

4. Sound reflection and absorption

   • Sound energy is reflected from hard surfaces such as walls and rocks.
   • Echolocation
     • The sounds bounce off the walls of the caves and the bats use the echoes to find their way about. Also bats prey, Sonar is a form of underwater echo location. Boats use sonar to locate underwaterreefs or shoals of fish

5. The decibel scale

   • The loudness of a sound is measureed in decibels (dB).
     • Loud sounds can damage your hearing. Short exposure to sound levels above 130 dB or long-term exposure to levels above 100 dB can cause permanent damage.

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