A sound wave is a transfer of energy as it travels away from a vibrating source. Sound waves are formed when a vibrating object causes the surrounding medium to vibrate. A medium is a material (solid, liquid or gas) which a wave travels through. As sound waves move through a medium the particles vibrate forwards and backwards. A sound's volume, how loud or soft it is, depends on the sound wave. The more energy put into making a sound or a sound wave, the louder the volume will be. The father a sound wave travels, the more it spreads, this makes it more difficult for us to hear a sound. So the nearer you are to a sound the louder it sounds to us. A sound wave enters the ear and is changed into nerve signals, which are interpreted by the brain.12
There are three aspects of a sound wave that cause different types of sounds to be produced, frequency, wavelength, and amplitude. Sound waves vibrate at different rates or frequencies as they move through the air. Frequency is measured in cycles per second, or Hertz (HZ).13
1 Hertz = 1 vibration/second
Sound travels at 330 meters per second or 740 miles per hour. Sound travels the fastest through solids and the slowest through gases. The faster an object vibrates the higher the frequency, which causes the pitch of the sound to be higher. The higher the frequency sounds come from shorter wavelengths. A wavelength is one aspect of a sound wave. A wavelength is the length of one cycle of sound. The period of a sound wave is the time taken for one wavelength to pass a certain point before a new wave begins to pass by. Longer wavelengths have a lower pitch. The lowest tones that your ears can hear are about 16 vibrations per second, or 16 Hz. Amplitude specifies the sound's loudness. A low amplitude will produce a soft sound and a higher amplitude will produce a louder sound.14
