How tall can you stack?
You will stack cups using one hand and count the standing layers. Each new cup raises the tower, so a tiny lean can become a big problem.
- Build
- Starter
- About 10 minutes
Grown-up needed: yes for setup, nearby supervision and clearing spills or loose pieces
What you need
- Ten paper or plastic cups
- A flat table
- Paper and pencil for a count
The rule
One hand only.
How to do it
- Place three cups upside down in a small triangle on the table.
- Use one hand to place a cup on the widest supported area.
- Add another cup while keeping its weight above the base.
- Let go of the tower before counting its standing cups.
- Rebuild with a different bottom arrangement using the same cups.
Why it works
A tower stays upright when its combined weight acts over the area supporting it. A broad base allows more leaning before that line falls outside the support. Adding cups higher up raises the centre of mass and can make tipping easier. Cups also need firm contact; an edge can slip even when the base is wide. Compare arrangements with the same cups to see whether width, height or contact caused the first wobble.
Make it harder
- Use a narrower base.
- Repeat with the other hand.
- Reach the same height using a different arrangement.
Ask Taz
- Why does a wide base help a tower stand?
- Why does a tall tower tip more easily?
- Why does one slipping cup bring others down?
For grown-ups
Give your child room to rebuild without racing or reaching above shoulder height. Notice whether they explain a fall through height, base width or contact. Counting cups is useful, but the explanation matters too. Ask at dinner: “Where would you put an extra cup to help the tower stay upright?”
Taz is an AI and can be wrong, so stay close by. Read how safety works on Taz.
Show us yours
Film your hands and what you made, not your face or name. Ask a grown-up before posting anywhere else.
Questions parents ask
Do we need special equipment?
Use the household items listed above. Begin with a small attempt on a clear surface before trying any harder version. The listed time is an estimate, so leave room to rebuild or repeat without rushing.
What if the first attempt does not work?
Notice where the result first changed. Alter one feature, keep the rest similar and try again. An unsuccessful attempt can still give you a useful question.
Do we have to post the result?
No. You can show it to a grown-up at home. Online sharing is optional and needs the permissions in the privacy line above.
More to try
See all Taz Challenges, or look through the science labs. One place for every why. Ask for early access at aitaz.com