Packing mass into volume

Science · Matter & Materials · ages 15-16

Name ______________________ Date ____________

Which set of units fits density?
- Joules per second
- Newtons per square metre
- Kilograms per cubic metre
How do you calculate density?
- Mass divided by volume
- Volume divided by mass
- Mass plus volume
Two lumps can have the same mass but very different densities.
Circle one: True False
A block has density 4 g per cubic centimetre and volume 50 cubic centimetres. What is its mass in grams?
Answer: ______________
A stone weighs 300 g and pushes water up by 100 cubic centimetres. What is its density?
- 3 g per cubic centimetre
- 30 g per cubic centimetre
- 300 g per cubic centimetre
Why is swimming in the sea easier than in a pool?
- Sea water is colder
- Sea water has bigger waves
- Sea water is denser, so it pushes up harder
A sealed syringe of air is warmed so its volume grows. What happens to its density?
- It rises
- It falls
- It stays the same
A student says a gas sample is dense because its particles move fast. What is wrong?
- Gases have no mass
- Speed does not set density, wide spacing does
- Gases cannot be weighed

Answer key

For grown-ups. Fold this page away before handing over the rest.

Kilograms per cubic metre · Density is mass over volume, so its units match that.
Mass divided by volume · Density packs mass and volume into one number by dividing.
True · Equal mass with different volumes gives different densities.
200 · Mass equals density times volume.
3 g per cubic centimetre · Divide 300 g by 100 cubic centimetres to get 3.
Sea water is denser, so it pushes up harder · Denser fluid gives a stronger upward push on the swimmer.
It falls · The same mass now fills a bigger volume.
Speed does not set density, wide spacing does · Gas particles fly far apart, so density stays low whatever their speed.