We started our sound unit last week by discussing what sound is - can it be seen, observed, touched etc. After they realised that sound is caused by vibrations we took it abit further with a number of activities.
We dropped pebbles into water to see what vibrations look like,
looked at rice/beans bouncing when a drum is hit,
observed sound using torchlight (reflected torchlight off of cling film wrapped around the end of a tube - when you speak into the tube the vibrations are visible in the reflected light)
used string wrapped around our fingers to hear sounds when our ears were blocked,
(the vibrations from the metal rod banging against the table travel up the string, along your fingers and into your ear so you can 'hear' it)
watched the sound vibrations put out a candle flame (cut the bottom off a bottle, cover in a cut balloon and flick the balloon to make a sound - the vibrations blow out the candle)
and demonstrated how the air molecules collide with a coathanger and some beads (think executive desk toy and you're close).
We finished by watching a great video on Brainpop all about sound.