1. SOUND UNIT
VOCABULARY

2. SOUND WAVES
Vibrations that spreads away from a vibrating
object
• Drop a pebble into a pond the waves go away
from where the pebble was dropped

3. RAREFACTION
 Part of a sound wave where molecules are spread out

4. HERTZ
 how frequency is measured (one vibration/second is one hertz Hz)
• Unit of measure

5. VOLUME
 how loud or soft something is (depends on the amount of energy
in the sound wave)

6. DECIBEL
 how volume is measured (dB) F 59 Chart of decibels

7. ECHO
 reflected sound wave (singing in the shower)

8. ECHOLOCATION
 finding things or navigating using sonar (bats, whales, dolphins use
this) Echolocation

9. DOPPLER EFFECT
 change in frequency and pitch as a sound moves towards or away
from you (named for scientist Christian Doppler who discovered it)
 Doppler

10. QUALITY
 what makes a sound different from another sound of same volume
and pitch (2 singers same note, same pitch, one is better)

11. FUNDAMENTAL
 main or basic (fundamental frequency is the lowest frequency
something vibrates, guitar string after it is strummed)

12. OVERTONE
 vibrating at a higher frequency (more times) than the fundamental

13. RESONANCE
 a fullness and richness of sound, build up of vibration (it
“resonates” with you)

14. MICROPHONE-
 an instrument that amplifies sound

15. ABSORPTION
 disappearance of a sound wave into a surface (think of a towel
absorbing) hard surfaces sounds bounce off, soft ones it absorbs