Science 8 - Sounds

1. TRY THIS!
Place your fingers over your throat and hum your favorite
song!

2. TRY THIS!
How do you think your vocal chords makes a sound?

3. PROPAGATION
OF
SOUNDS!

4. Sound is ….
• produced when matters vibrates.
• These vibrations travel outwards
the source.
• Sound consist of waves and these
waves travel as a Longitudinal
Wave.

5. Medium is ….
Any material or substance
which can propagate
Waves or Energy.

6. Longitudinal Wave:
• Waves that are usually created by
pulling and pushing the material
or medium.
• Alternating compressions and
rarefactions are observed.

7. Longitudinal Wave:
- Compressions and rarefactions moves along with the
direction of pushing and pulling activity of the material.
Thus, the waves are parallel to the motion of the
material or the particles of the medium.

8. Transverse Wave:
• Medium or the channel moves perpendicular
to the direction of the wave. Here, the
particles move up and down as the waves
move horizontally.

9. Can Sound
Waves travel in
Solid, Liquid or
Gas?

10. Yes!
- Sound Waves can travel through solids,
liquids and gases but NOT through a
Vacuum.

11. Sounds in Different Mediums
• Sound waves that travel in Air
come in contact with our
eardrums causing it to vibrate.
• People hearing sounds while
submerged in a pool is
evidence sounds travels
through a liquid.
• People hearing sounds with
their ear pressed against a
table is evidence sound travels
through solid.