Solids, liquids, and gases: sorting by how they act

Science · Matter & Materials · ages 8-9

Name ______________________ Date ____________

Which describes a gas?
- It keeps a fixed shape
- It flows but takes the shape of the container
- It spreads out and fills all the space it can
Which describes a solid?
- It flows and takes the shape of its container
- It keeps its own fixed shape
- It spreads out to fill all the space around it
Milk is a liquid because it flows and takes the shape of its cup.
Circle one: True False
Tom is sorting a wooden block, a puddle of water, and the air in a balloon. Which group is correct?
- Block: solid, Water: liquid, Air: gas
- Block: liquid, Water: solid, Air: gas
- Block: solid, Water: gas, Air: liquid
Which group are all liquids?
- Juice, honey, milk
- Rock, ice cube, brick
- Steam, smoke, air
Sand is a liquid because it can be poured from one container to another.
Circle one: True False
A shopkeeper sorts bricks (solid), cooking oil (liquid), and helium in balloons (gas). Toothpaste flows slowly but holds a squiggly shape when squeezed out. Which group fits best?
- Solid, because it holds a shape
- Liquid, because it flows when squeezed
- Gas, because it can be squeezed
Priya sees a white cloud rising from a boiling kettle and says, 'That's the gas, steam.' What is wrong with her idea?
- Nothing is wrong, that white cloud is the gas
- The white cloud is tiny liquid droplets, not the gas itself
- The white cloud is ice crystals forming in the air

Answer key

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

It spreads out and fills all the space it can · Gases spread out until they fill whatever space they are in.
It keeps its own fixed shape · Solids keep a fixed shape, whether or not they are in a container.
True · Milk pours and shapes itself to whatever holds it, so it is a liquid.
Block: solid, Water: liquid, Air: gas · The block keeps its shape (solid), the water takes the puddle's shape (liquid), and the air spreads to fill the balloon (gas).
Juice, honey, milk · Juice, honey, and milk all flow and take the shape of their container.
False · Sand only looks like it flows. Each grain is a hard solid; the grains just slide past each other.
Liquid, because it flows when squeezed · Toothpaste flows and takes the shape of its tube, which puts it closest to the liquids, even though it holds its shape too.
The white cloud is tiny liquid droplets, not the gas itself · Real steam gas cannot be seen. The visible cloud is water that has already cooled back into tiny liquid droplets.