1. WHAT IS
SOUND ENERGY?
CHAPTER 14 SECTION 2

2. SOUND a wave of vibrations that spreads from its source.
Vibration is the back-and-forth motion of an object.

3. Crest - areas where particles are very close together
Frequency - The number of crests that pass by a point each second
The greater the frequency is, the higher the pitch of the sound

4. Why Are Some Sounds Louder Than Others?
The source of the louder sounds is vibrating more.
These sound waves have more energy.
A sound’s loudness can be measured in units called decibels.

5. YOUR VOICE Your vocal cords vibrate when you talk.
The vibrations are caused by air rushing past them.
Your vocal cords make the particles in the air around them vibrate.
These vibrations travel outward through the air as sound waves.

7. How Does Sound Behave?
Sound can travel through solids, liquids, and gases
It cannot travel through a vacuum, which is empty space that contains no particles
The speed at which sound waves travel is different in different materials.

8. Sound Transfers Energy
For a sound to be heard, energy must first cause an object to vibrate.
Vibrating objects give off energy in sound waves in air.
Some of the energy reaches your ear, and your eardrum absorbs some of the energy.
In this way, the energy of the original material’s vibrations passes to you.