(WVS) Mechanical Waves Lesson

Mechanical Waves

Waves are everywhere! In the air, in water, and even in solid objects, visible and invisible, waves carry information - sometimes useful (like speech or TV data) and sometimes purely incidental (waves in the sea, or noise in the street).  Whether you realize it or not, our lives are dominated by waves.  

To introduce us to the topic of waves, please watch the videos below.  As you watch the video be sure to listen for how energy and waves are related, the types of waves, the parts of various waves, and how wave speed is affected.

Visible waves are probably the easiest to think about, and many types of mechanical oscillation generate visible waves. Have a look at the example below: a group of people jump up and sit back down in sequence...

..note that something (we could call it information) travels from left to right, but the people themselves only stand up and sit down - no one swaps seats. Here the medium in which the wave propagates is 'people'...no people = no waves. The wave is mechanical - no electrical or acoustic stuff is happening, just a physical movement. In general, mechanical waves are transmitted by vibrating particles (in this case the particles are the people), but although they oscillate (stand up / sit down) the particles do not move from their normal position.

Waves transport energy without transporting any matter. Mechanical waves must travel through a medium. A medium is the matter (solid, liquid, or gas) that the wave is traveling through.  Examples include ocean waves traveling through water, earthquakes releasing energy to create waves that are powerful enough to travel through the rock of the Earth, and sound waves traveling through the air to your ears. A wave is simply the disturbance of a medium by moving energy.

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