What's Going On?

Bottle orchestra

Activity overview

15 mins
Ages 7 – 9

Science topics:


Spark a conversation with these musical bottles! This activity is great for describing observations and applying ideas in unfamiliar contexts.

Run the activity

1. You’re going to watch a short video. The aim isn't to find right answers, it's to explore ideas and find out what they know.

  • Do they know what might happen based on the image?

2. After you've watched the video, lead a discussion with your class:

  • Why do the class think the bottles are lined up like this?
  • What do they think will happen to each bottle when they're tapped?
  • Why do the class think there are different levels of liquid in each bottle?
  • How do they think the sound is made?

3. Ask the class to describe what they saw using only one word.

Background science

This video shows how many notes you can make with a few glass bottles and some liquid! When you tap an empty glass bottle the glass vibrates and makes a sound, or note. Adding liquid to each bottle slows the speed of the vibrations of the glass. Slower vibrations lower the pitch, so a bottle full of water has a low pitch and an emptier bottle has a higher pitch. We’ve used coloured liquid to make this really clear, but plain water works just as well.

Take it further

If you recreate this activity in the classroom and blow over the mouths of the bottles, rather than tap them, you'll get a completely different result. The bottle with the smallest amount of water, that made a high note when tapped, will make a low note when blown. This is because when you blow over a bottle you're vibrating the air, not the bottle! 
You could continue to explore sound with this Rice and rhythm What’s Going On?, or with this brilliant activity from the Science Museum that explores how sound travels in a really fun way! 

Image and video credit: Wellcome