Same-Volume Bottles: Shapes, Volume and Buoyancy

Six bottles in very different shapes (sphere, pyramid, star, heart, twist, torus) that all hold about the same amount: 150 to 160 mL. They stack and balance in surprising ways and float.

Young learners discover that a tall bottle and a squat one can hold the same volume (conservation of volume), and explore balance and floating in a water tray.

Design by Yxaj on Printables, shared under CC0 1.0 (public domain). The files and photos are the designer's, unchanged.

1. Print without supports at 0.16 mm layers.
2. Ask: which bottle holds the most? Let children guess, then pour water from one to another to find out.
3. Stacking challenge: how tall a tower can you build?
4. In a water tray: which ones float upright, and what happens as you fill them?