Sound Waves

Definition for Today Class’

Resonance - Rhythm with which you push, produce a large amplitude.

Sound of Reflection - the repetition of a sound resulting from reflection of the sound waves. (Echoes)

Sound of Refraction - The turning or bending of any wave, such as a sound wave, when it passes from one medium into another of different optical density.

Forced Vibration — The oscillation of a system under the action of a forcing function. Typically forced vibration occurs at the frequency of the exciting force.

temperature inversion - condition in which the temperature of the atmosphere increases with altitude in contrast to the normal decrease with altitude.

Out of Phase - an unsynchronized of sound

On the beginning of the class Ms K. Hand back our notes that we done yesterday. Ms K. show another video of Paul Hewitt about Sound Wave. On the first scene of the video, Paul talked about how the dolphin communicates to each other. He also talked about which sound will travel fastest, is it in Cold weather or Warm weather? à Paul answer is warm weather, because the air is less dense and also a collision of molecules of air in warm air is greater. Paul Hewwit also talked the gAng about which can you hear well is it Day time or Night time. à Paul answer is Night time, because the sound waves are bent when they travel from cold air into warm air. (Related: Refraction of sound).

Also he demo to the video how does resonance work. Click the link below to view the demo. à http://www.youtube.com/watch?v=zWKiWaiM3Pw&feature=fvwrel

. ‘’ It is not how hard you push the swing it is about the rhythm how you push the swing’’ à(Resonance)

After Paul lecturing to the gAng, he show the video about the Tacoma Narrow bridge that was a tragedy to the Washington people where the Cat fault... kiddingJ. The bridge collapse because the oscillating of the wind into the bridge. After the cat destroyed the bridge the video ended and Ms K gave us some time to finish our lab report but luckily she gave us more time to hand in the lab tomorrow. Ms K asked us to read the booklet page 1-6.

Next Scribe: BryanC.