This applies to all waves, including light waves and even waves on the sea: woooo-woooo' (or a passing race-car sounds like 'eeee-yoooo'): Through this, we can make a very important observation Sound waves rely on the medium for. Blocking your ears creates a discontinuity in the medium due to which the flow of sound energy is disturbed. SOUND WAVE meaning: a wave that is formed when a sound is made and that moves through the air and carries the sound to your ear. So a passing siren sounds like 'nee-nee-nee-nee . The sound waves travelling around you are now unable to get through to your ear or the intensity of the sound you hear is greatly reduced. And as the source moves away the waves have a lower frequency.As the source approaches, the waves arrive at a higher frequency.The Doppler Effect happens when a wave's source is moving in relation to us: They send out ultrasound squeaks (20 kHz to 120 kHz) to find their way at night, find insects to eat and even avoid hitting small wires!Īnd ultrasound can be used for images inside our bodies. Sonar (with computer help) can map out the sea floor and even find shipwrecks!īats use a similar method (called 'echolocation'). Sonar ( SOund Navigation And Ranging) is a way of listening to the echo of sound waves (usually underwater) to locate objects: You will hear the echo of the clap some time after you hear it from your hands. The sound bounces off the wall (angle in matches angle out). EchoĪn echo is a reflection, usually of sound from a hard surface.

So if you count 15 seconds until you hear thunder, the lightning strike was 5 km (3 miles) away. The light reaches you almost immediately (at about 300,000 km/s), but the sound takes longer.ģ43 m/s is about 3 seconds per km, or 5 seconds per mile.

It also has a wavelength associated with it. Next time there is a thunderstorm watch for lightning and start counting seconds. A sound wave is a simple pressure wave that is caused by the movement of air molecules away from the source and like all waves we expect it to have a frequency and an amplitude.

Soundwaves definition