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Science project idea

Rain stick from a cardboard tube: the sound of falling rain

Many grains falling past obstacles make a sound like rain. We hear the vibrations of grains hitting the tube walls and the pins.

Make it yourself8 numbered steps, the materials and the science, all free.Go to the stepsGet a ready-made kitReady-made models, kits and spare parts in the store under Best Out of Waste.Browse Best Out of WasteAsk on WhatsAppAsk the head office whether a model or kit for this idea is available.Send a message

What it shows

Many grains falling past obstacles make a sound like rain. We hear the vibrations of grains hitting the tube walls and the pins.

The science

When rice falls, each grain hits a toothpick or the wall and sets it vibrating, making a small tick. Hundreds of ticks one after another sound like rain. Fewer sticks make a slower fall and a longer sound. The tube makes the sound louder because the air inside vibrates too.

Materials

Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.

  • A long cardboard tube from a foil or wrapping roll (free)
  • About 40 toothpicks or short pins
  • Rice or dal, a handful
  • Two circles of cardboard for the ends
  • Tape and glue
  • Paint or coloured paper

Safety

For this project: An adult must push in the toothpicks and cut the cardboard. Keep sharp ends inside the tube.

Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.

All the safety rules

Step by step

8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.

  1. Close one end of the tube with a cardboard circle and tape it tightly.

  2. Push toothpicks through the tube in a spiral around it, about 2 cm apart.

  3. Break or cut off the toothpick ends that stick out and tape over them.

  4. Pour a handful of rice into the open end.

  5. Close the other end with the second circle and tape it.

  6. Tilt the tube slowly and listen to the sound.

  7. Decorate the tube with paint and paper.

  8. Compare the sound with more rice and less rice.

What you should see

Tilting the stick makes a gentle sound like rain. More rice gives a longer sound.

Viva questions

A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.

1What makes the sound?

Grains hitting the sticks and the wall.

2Why does it last long?

Grains fall slowly past many sticks.

3What does the tube do?

It makes the sound louder.

4Where are rain sticks used?

In some traditional music.

Free ebook: Viva Questions for Science Projects

Take it further

Use lentils or sand instead of rice and compare the sound.

Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.

Free ebooks for this project

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