1. Sound

2. If a tree falls in the forest and there is nobody around does it make a sound?

3. Sound Disturbance (energy source) Medium (wave travels through) Air Water Steel

4. Sound in (Medium) Air Compression waves travel through air Sound wave are called Longitudinal Waves

5. Sound in (Medium) Air Sound can not travel in a vacuum

6. Speed of Sound The speed of sound in dry air at 0 o C is about 330 meters per second( 330m/s ) 770 miles per hour mph

7. Speed of Sound Water vapors in the air increase the speed of sound slightly

8. Speed of Sound Increase in temperature also increases the speed of sound For each 0 o C, the speed of sound in air increases by 0.06m/s Example: At normal room temperature of about 20 0 C sound travels at about 340m/s

9. Loudness Loudness is sound intensity. The greater the disturbance (intensity) the greater the sound wave Loudness is measured in units of Decibel (dB)

11. Forced Vibration The transfer of vibration from the primary medium to secondary medium, increasing amplitude

12. Natural Frequency When an object composed of an elastic material is disturbed, it vibrates at its own special set of frequency, which together forms a special sound. We speak of an object’s natural frequency, which depends on factors such as the elasticity and shape of the object

13. Resonance When the frequency of a forced vibration on an object matches the Object’s natural frequency, a dramatic increase in amplitude occurs This phenomenon is called resonance. Resonance means to re-sound or sound again.