1. Today is Tuesday, May 7th, 2013 Homework:
Homework Packet Due this Friday
Finish Reading Ch. 14 by Friday
Ch Combined Test on Monday, May 13th
Warm UP:
Discuss with your shoulder partner:
What are some ways that you interact with light and sound in your daily lives?

2. Goal for Today
SWBAT demonstrate the ability to recognize various forms of energy by exploring how sound energy behaves and transfers.

3. Sound…. Sound is a vibration that spreads from its source
Must travel through a material; molecules vibrate in a pattern
A basic sound wave:
Compressions – areas where particles are very close together
Rarefactions – areas where particles are far apart
Wavelength – distance between crests
Frequency – measure of how fast particles are vibrating. Greater frequency, higher pitch the sound
Pitch is related to frequency
Decibels – units that measure sounds loudness
Volume is related to amount of vibration. Louder the sound, the higher the crest (or the energy squeezes particles closer together)

6. Place your hands on your vocal chords. Make a sound
Place your hands on your vocal chords. Make a sound. Do you feel it vibrate
Vocal chords cause the air that passes through to vibrate
Where else do you see vibrations when sound is made?
Sound energy can travel through solids, liquids and gases. Can’t travel through a vacuum. Why?

7. When sound energy reaches the border of a new material, 3 things can happen: 1) bounce back, 2) be absorbed, 3) pass through
Sounds travels at different speeds in different materials and when conditions of a material change
Echo results when sound is reflected back
In a soundproof room, sound is bounced and absorbed. Each time sound bounces, material vibrates and some of the energy is turned to thermal energy
For sound to be heard, the energy from the vibrations must be transferred (through the air to your ear to your eardrum)

8. Closing it up….
Let’s see what Tim and Moby have to say….