Floating foil and sinking foil

About the video

In the video two balls of the same foil behave differently: one floats and one sinks. At home your child cuts three 20 cm squares, crushes one in the air and one under water, lays the third flat, and watches all three in a bowl of water for 1 minute.

Aluminium is 2.7 times denser than water, but whether a ball floats depends on its average density, including what is trapped inside. A ball crushed in air traps air and floats, while a ball crushed under water fills with water and sinks.

What your child learns

• Explain floating and sinking with average density
• Calculate density from mass and volume
• Compare densities using >, < and =

What's on the worksheet

1. 1Predict first
2. 2Record your results
3. 3What did you see?
4. 4The science behind it
5. 5Key words
6. 6Calculate the density
7. 7Compare the densities
8. 8True or false
9. 9Explain it