Sound

Sound

1. Waves

   • A wave is an oscillation or vibration that transfers energy or information
   • Amplitude- The distance from the middle to the top or bottom of a wave
   • Frequency-The number of waves that go past a particular point per second
   • Wavelength-The distance from one point on a wave to the same point on the next wave
   • The top of a wave is called a peak or crest and the bottom of a wave is called a trough
   • In a transverse wave you can move hand at right angles to the spring. At 90 degrees
   • If you push and pull you create a longotidinal wave.
   • when waves are put together they superpose. Which means that they add up or cancel out

2. Sound and energy transfer

   • A vibration produces a sound wave
   • Sound needs a medium like a solid, liquid or gas to travel through
     • It cannot travel through empty space, a vacuum as there isn't any air molecules to vibrate
   • Sound travels at 340m/s in air
   • Sound travels fastest in solids
     • In steel it can travel at 500m/s
   • The speed of light is 300,000,000 m/s
     • It is almost a million times faster than sound

3. Loudness and pitch

   • You can plug a microphone into an oscilloscope to see what the sound of your voice looks like
   • A high sound has a higher frequency than a low sound
   • You have the biggest audible range when you are younger 20-20,000Hz
   • Frequency is measured in Hertz

4. Detecting sound

   • Your ear detects sound waves
   • You measure sound intensity in decibles
   • very loud sounds or head injuries can permanently damage your hearing
     • A build up of ear wax can also be damaging
   • Your hearing can be damaged if a sharp object makes a hole in your eardrum, but your eardrum will gr0w back

5. Echoes and ultrasound

   • when sound reflects of a surface it produces an echo