An iron nail sinks, yet a ship made of iron floats

Why does a lump of iron float?

Board 1 · Put things in the tank

Drag the things below and drop them into the tank. Finish by pouring in the jar of salt.

An empty glass tank on a grey table

Fresh water

Board 2 · Load the ship

This ship is made of iron. Drag the crates onto the deck one at a time. The gold line on its side marks how far it may safely be loaded.

Fresh water

The story behind this board

It reads far more easily after you have tried it.

Ships — why a lump of iron floats, and why there is a bulge under the bow Buoyancy Density Archimedes — a thought in the bath
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