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Weird Whirring Widget
Feel like throwing your recorder through a wall? Feel some good vibrations and become a noisy nuisance with this wacky instrument.
Australian Curriculum links
- Science > Physical Sciences > Year 1 > ACSSU020
- Science > Science as a Human Endeavour > Year 1 > ACSHE022
You'll need
- Two pop sticks (from a craft shop or ice blocks)
- Large, wide rubber band, about 6mm thick and 9cm long when not stretched
- Scissors
- 1 plastic drinking straw
- 2 small, thin rubber bands, about 6.5cm long when not stretched
Try this
- Use the scissors to cut two pieces from the straw, each about 3cm in length and wrap the large rubber band length-ways around one of the pop sticks.
- Place one of the pieces of straw under the large rubber band, close to one end of the pop stick. The straw should be at right angles to the pop stick.
- Lay the second pop stick on top of the first one so the straw is in between the pop sticks.
- Use one of the small, thin rubber bands to tie the two pop sticks together at the end that has the piece of straw by wrapping the rubber band around the sticks until it is tight.
- Place the other piece of straw between the second pop stick and the large rubber band, at the opposite end to the other piece of straw.
- Use a small rubber band to tie the two pop sticks together at the end that has the second piece of straw.
- Hold your ‘widget’ with one end in each hand, place your lips on the pop sticks and blow between them to make the rubber band vibrate. Listen to what happens to the sound if you blow harder or softer. Move the pieces of straw closer together and notice what happens to the sound.
Further investigation
Try making four ‘widgets’ and tune them by moving the pieces of straw to change the pitch. With a few helpers, each playing a different note, try playing a simple tune like Mary Had a Little Lamb.
What's happening?
All sounds are produced by vibrations and a vibration is simply something moving backwards and forwards. When you blow into the widget, you make the large rubber band vibrate, and that vibration produces a sound. Fast vibrations result in high sounds and slower vibrations give lower sounds. Blowing harder into the widget makes the rubber band vibrate faster, and the pitch should become higher.
Long or large objects vibrate more slowly and produce a lower-pitched sound, whilst shorter or smaller objects vibrate quickly and produce a higher-pitched sound. When you move the straws closer together, you shorten the part of the rubber bands that is vibrating, so the pitch becomes higher.
Real world links
The frequency of sound is measured in hertz (Hz) which is the number of times something vibrates (moves back and forth) every second. Humans can only hear sounds with frequencies between 20 Hz and 20,000 Hz. As a person grows older, the range of sounds they can hear becomes smaller and they may not be able to hear very high or very low sounds. Some animals can hear higher or lower sounds than humans, for example, dogs and bats can hear very high sounds and whales can hear very low sounds that humans cannot hear.