Sound

Sound Master Document (contains the unit outline with links to all documents)

This video shows an example of how resonance can have destructive effects!  The sound waves generated by the speaker cause the glass to begin to vibrate.  The black object on the left is a high-frequency speaker.  Note:  It is NOT touching the glass!  It is putting out a sound wave that matches the resonant frequency of the wine glass.   Eventually the movement of the glass is too much, and it breaks!

Another example of resonance’s destruction.  The wind blowing by the bridge matched the resonance frequency of the bridge.  Like the wine glass, eventually the structure of the bridge was not flexible enough to withstand all the motion, so the bridge broke apart.   This bridge is about 3 hours from my home town!

The infamous and all-too-catchy Echolocation song.  Marine mammals (porpoises, dolphins, whales, etc.) and bats are the most well-known users of echolocation.  By sending out a sound wave (usually higher than human ears can hear), then listening for how long it takes to come back, these animals are able to locate objects without using their eyes!  Not only can they determine the distance of the object, but the direction as well.   Sonar is basically humans trying to do the same thing…..

Using sonar to detect the depth of the ocean can tell us what the bottom of the sea floor looks like.  Is it flat?  Bumpy?  Are there canyons, mountains, or perhaps a sunken ship?