Sound
Sound is the rapid compression and expansion of molecules in fluids and solids.
Characeristics of Sound
Loudness: the amplitude of the vibrations
| Soft | LOUD |
|---|---|
A 256 Hz tone |
A 256 Hz tone four times bigger in amplitude |
Question: Does the loud tone sound four times louder?
- Frequency: how rapidly the vibrations occur
| Low-Frequency | High-Frequency |
|---|---|
| A 256 Hz tone |
A 512 Hz tone |
Question: Does the high-frequency tone sound twice as high?
- Location: where is the sound coming from?
| Low-Frequency | High-Frequency |
|---|---|
| Locate based on time differences: It takes longer for sound to travel to the left ear than the right. Occurs for frequencies less than 1,000 Hz.  |
Locate based on amplitude differences: The sound at the right ear is louder than at the left. Occurs for frequencies greater than about 5,000 Hz.  |