Making a shaker loud or soft
Physics · Key Stage 1 · The School
Building a simple shaker
A shaker is just a closed container with something loose inside. Take an empty bottle. Put a material inside. Close the lid tightly. Shake it. The material bounces around inside and makes a sound. Different materials sound completely different.
Predicting before shaking
Before shaking, look at your material and predict. Rice: will it be loud or quiet? Cotton wool: loud or quiet? Paperclips: loud or quiet? Say your guess out loud first. Then shake each one and check if you were right.
It is not just about how hard you shake
Shake a bottle of paperclips gently. It is still fairly loud. Shake a bottle of cotton wool as hard as you can. It stays quiet. The material inside matters just as much as how hard you shake, sometimes even more.
Testing five materials fairly
Put rice, dried pasta, paperclips, cotton wool and dried beans into five identical bottles, one material per bottle. Give each bottle exactly the same three shakes, no harder, no softer. Line them up from loudest to quietest. Hard materials like paperclips and pasta make sharp, loud sounds. Soft materials like cotton wool make almost no sound at all. Same shake every time. Only the material changed, and that alone explains the whole order.
Making your own instrument
Now build your own shaker. Choose a material on purpose, for a loud rattle or a soft hiss. Test it. If it is not right, swap the material and test again. That is exactly how a real instrument gets designed.