In space there is a vacuum and this is about the only thing
sound does not travel through. You can scream your head off
and no-one will hear you!
Instruments like woodblocks and cymbals make sounds like noises.
This is because they make waves that do not make a pattern.
The note middle A is made when something vibrates at 440 times
per second.
The next A (8 steps or an octave higher)
is made by a vibration that is twice as fast (880Hz).
Double the speed of vibration and
you get the next note higher with the same name.
This is called an octave.
There
is a huge amount of energy in thunder.
Have
you ever felt the vibrations from a big lorry passing
by. The sound is strong enough to shake the ground.
Sound
(or sonic) vibrations are used to clean complicated
mechanical objects in a tub of liquid.
You
can now even use sound to clean your teeth (in a sonic
toothbrush the vibrations kill the bacteria on your
teeth and gums).
Two different
people playing the same instrument make different sounds.
Plucking a string has a different timbre to bowing it.