Floating and sinking
Chemistry · Early Years · The School
Guess first, then test
Before you drop anything in the water, SAY what you think will happen. Guessing first is what makes it an experiment instead of just playing. A cork, a coin, a stick, a stone, a plastic lid — write down or say your guess for each one, then try it.
Big things can float
This is the surprise. A tiny coin sinks and an enormous log floats. So it is not about how big something is. Ask what else might matter: what it is made of, and whether it is hollow. A closed plastic bottle floats; fill it with water and it sinks.
Boats
Metal sinks — but a metal ship floats, because it is a shell with air inside. Try it with foil: a screwed-up ball sinks, and the same foil shaped into a little boat floats. Same material, same amount, different shape.