Play a tune on glasses
You will listen to gentle taps on glasses with different water levels. Similar-looking glasses can make different notes, so start with matching ones if your household has them.
- Science
- Starter
- About 15 minutes
Help needed: yes for setup, nearby supervision and handling water or small items
What you need
- Five intact drinking glasses selected by someone
- Water
- A wooden spoon
- A tray
The rule
Tap gently.
How to do it
- Ask someone to check and place the glasses firmly on a tray.
- Have them fill the glasses to five different levels.
- Tap the outside of the first glass very lightly with the wooden spoon.
- Listen before gently tapping the next glass.
- Arrange the heard notes from lower to higher.
- Ask the helper to move the filled glasses away afterwards.
Why it works
Tapping makes the glass vibrate, and its movement sends sound into the air. Water couples to that vibration, changing the effective moving load and often lowering the main tapped note as the level rises. The glass’s shape and thickness also affect its sound. Blowing over a bottle is a different experiment, so its water-level rule should not replace this one. Matched glasses help you hear the effect of water without confusing it with different containers.
Make it harder
- Compare two nearly matching water levels.
- Play three gentle notes in a chosen order.
- Predict the change before someone adds a little water to one glass.
Ask Taz
- Why does a tapped glass make a note?
- Why can more water lower the tapped note?
- Why do different glasses sound different at the same fill?
Before you start
A helper stays throughout, checks the glasses and stops the activity immediately if anything chips or cracks. Use tiny taps rather than volume. The aim is listening and comparison, with no pressure to reproduce a tune exactly. Ask at dinner: “Which other feature could change a note besides the water level?”
Taz is an AI and can be wrong, so check what matters. Read how safety works on Taz.
Show us yours
Film your hands and what you made, not your face or name. If you are under 18, ask a parent or guardian before posting anywhere else.
Common questions
Can we use what we already have?
Start with the listed household materials. Keep the basic setup small and choose suitable items before beginning. The stated time is an estimate, so let the observation decide whether you need longer.
What should we record?
Note the prediction, the result and the one thing you changed. Keeping those separate helps everyone discuss what happened without turning an activity into a competition.
Must the result be shared online?
No. A conversation at home is enough. If you choose to share, keep identifying details out and follow the privacy line above.
More to try
See all Taz Challenges, or look through the science labs. One place for every why. Start exploring at aitaz.com
Try it in 3D: Sound waves.