Sink or Float

What your child learns

• Making a guess, then testing it, like a little scientist
• Whether something sinks or floats is not about being big or small, but about being heavy or light for its size
• Hollow things with air inside (ping-pong balls, empty bottles, rubber ducks) float
• Surprises: a big log floats while a tiny pebble sinks, and apples and ice cubes float too

How to play

1. Press "Play now". An object sits on a stool next to a tub of water and the voice asks "Will the rock sink or float?".
2. Tap "Sink" or "Float", or drag the object onto one of them. On a computer, use Tab and Enter.
3. The object drops into the tub with a splash, then bobs on top or sinks to the bottom, with a short "why".
4. A right guess earns a star. A wrong guess is fine too: it is a chance to learn something new.

For parents

• It starts with easy objects (wood, a rubber duck, a rock, a key); once your child guesses well, surprises like an apple, a coin and an ice cube appear.
• Only objects with a clear result in plain water are used; paper, eggs and oranges are left out because the result can change.
• Try it for real with a bowl of water: an apple, a spoon, a cork. Ask "Will it sink or float?" before each drop.
• Remind your child that heavy does not always mean sink: a big heavy log floats because wood is light for its size.