Chapter 2 Book O Page 35

What is sound, how do we hear? Sound is a movement of particles. Sound: Is a disturbance that travels through a medium as a longitudinal wave. How do we make sound? Sound occurs when particles start to vibrate and produce a wave. Time to try it. We are going to use tuning forks. When we hit one of these what will happen?

So what made the tuning fork ring? The ringing came from the two forks vibrating. We can see that in water. Next experiment: lets put the tuning forks and see if we can get them to show their waves in water. So what did we see in the water? So does this prove that there are waves. And that energy is being transferred.

As we saw in the water. Sound waves carry energy through a medium without moving the particles of the medium Each particle of the medium vibrates as the “disturbance “ passes. When the disturbance reaches your ears they vibrate agents your ear drum and you precive this vibration as sound.

When talking about interaction of sound waves we use words like reflection, diffraction, interference, elasticity density, and temperature All of these things can effect how we sense sound and how the sound travels. Who knows what an echo is. An echo is a reflection of sound from a hard and smooth surface. Today when you are in the gym, listen to all of the echo’s. apposed to being in here the carpet everywhere absorbs the sound.

Does anybody know what diffraction is? Diffraction is the ability of sound waves to travel around corners and through holes or openings Light waves do not have this ability Interference As we learned Earlier interference can be constructive or destructive depending on how they interact

The speed of sound depends on the elasticity, density, and temperature of the medium the sound travels through. Have you ever seen something happen like on the 4 th of July you see a firework go off a long way away then you hear the BANG, why? Does it matter weather it is warm or cold, air or water, ect. Yes Sound travels at different speeds through all of these variation.

The speed of sound depends on how close the particles are in the medium. Open your book to p. 39 book O the more solid the medium the faster sound will travel through it. How ever the more dense the material is in the same state(solid, gas, liquid) for the most part the slower the sound will travel. Lead is more dense than glass but sound travel faster through the glass faster.

Loudness : is the perception of the energy of the sound. Loudness depends on two things. 1 st the amount of energy it takes to create the sound, 2 nd the distance you are from the source of the sound. In general, the more energy use to make a sound the louder it is. And the closer you are to the source the louder it is.