scIENCE 5

1. Sound and
Matter

2. Sound – is an energy associated with
vibrations in matter.
– vibrations travel or move through
a medium and are heard when
they are detected by a receiver,
such as your ears.

3. Properties of Sound
• Pitch – the slowness or fastness of the
vibration of the sound
– Fast vibrations produce high-
pitched sounds
– Slow vibrations produce low-
pitched sounds

5. • Intensity – the loudness or softness of
the sound
– it depends on how hard the
vibrating source is struck

6. How Sound Travels?
Medium – the carrier of the sound from the
source to your ears
- solid, liquid, and gas
• Sound travels faster through a liquid than
through a gas.
• Solid medium is the best carrier of sound.

7. Materials that absorb sound:
– Acoustic foam
– Fiber
– Sponge
– Cotton
– Wool
– Cork

8. Materials that reflect sounds:
– Glass
– Wood
– Brick
– Concrete
• Echo – is sound that is reflected back to
its source

9. Sound Insulators:
– Carpets
– Curtains
– Fabric in furniture
– Canvas paintings

10. Threshold of hearing – the range at which
humans can pick up a vibration and
interpret it as sound
• Intensity of the sound is measured in
terms of decibels

11. • The near the sound source, the louder
the sound you hear.
• Sound can also be described in terms of
frequency or the number of waves that
it produces.

12. • Infrasonic Sounds
- sound frequency that is too low for
humans to hear
• Ultrasonic Sounds
- too high for humans to pickup