Back to activities

Indoor activity

Water Xylophone

Fill glass jars with different amounts of water, add rainbow food colouring, and tap them to play real musical notes — build your own instrument at home!

Ages 5-8 0-1 hours Education 7/10

Materials

  • Food Colouring
  • Glass Jar
  • Markers optional
  • Spoon

Illustrated Steps

1

Line Up Your Jars

Gather 6–8 matching glass jars and arrange them in a row on a towel-covered table. Identical jars give the clearest notes — jam jars or pasta sauce jars work perfectly.

2

Fill with Water

Fill the first jar nearly to the brim, then add less water to each jar so the last has only 2 cm. Each different level creates a different musical note.

3

Add Rainbow Colours

Add a few drops of a different food colouring to each jar and stir. Make a rainbow row — red, orange, yellow, green, blue, and purple.

4

Tap and Tune

Tap the rim of each jar gently with a metal spoon. The fuller jars play lower notes. Adjust water levels until you can pick out a clear musical scale.

What You’ll Create

You’ll transform ordinary glass jars into a shimmering rainbow xylophone 🌈🎶 that plays real musical notes! By filling each jar with a different amount of water and tapping with a spoon, you’ll discover how scientists and musicians both use the same magical principle — more water = lower pitch, less water = higher pitch. Your homemade instrument will actually play tunes!

How to Set It Up

Step 1: Line Up Your Jars

Gather 6–8 glass jars of the same size and arrange them in a row on a table covered with an old towel. Matching jars produce the clearest notes — try jam jars or clean empty pasta sauce jars!

Step 2: Fill with Water

Fill the first jar almost to the brim, then fill each jar with a little LESS water than the one before. The last jar should have only about 2 cm of water. Use a ruler to measure the water heights if you like precision!

Step 3: Add Rainbow Colours

Add a few drops of food colouring to each jar to make a rainbow row — red, orange, yellow, green, blue, and purple. Stir gently with the spoon. Now your xylophone looks as brilliant as it sounds! 🌈

Step 4: Tap and Tune

Gently tap the rim of each jar with a metal spoon. Listen! 👂 The fullest jar plays the lowest note. Adjust water levels up or down until you can pick out a clear musical scale — do-re-mi-fa-sol-la-ti-do. Now try tapping a simple tune like “Twinkle Twinkle”!

Have fun!

  • 🎵 Challenge each other: can you play a recognisable tune your family can identify?
  • 🔬 Cover one jar with your hand while tapping — does the sound change?
  • 💧 Add one drop of water at a time and listen to the pitch slowly rise
  • 🎤 Sing each note as you tap it to train your musical ear
  • 🎶 Record your musical creation and play it back!

Why It’s Amazing

  • Physics of Sound: Tapping the jar creates vibrations. More water = more mass = slower vibrations = lower pitch. This is real acoustics! 🔬
  • Mathematical Thinking: Ordering jars from most to least water develops sequencing and comparison skills. 📐
  • Musical Ear Training: Adjusting water levels to match a scale trains pitch recognition — a foundational music skill. 🎵
  • Creative Expression: Composing tunes on your homemade instrument nurtures musical creativity and confidence. 🌟

Pro Tips

For ages 5–8: Focus on making the rainbow beautiful and exploring free play. Don’t worry about exact pitches — just enjoy discovering the sounds!

For ages 8–12: Challenge them to tune the jars to a proper C major scale using a free tuning app on a phone. Real science and music theory combined!

⚠️ Use sturdy, wide-mouthed glass jars and tap very gently with a metal spoon. Supervise younger children with glassware at all times.