# Tests for Solids and Liquids

Students consider simple ways of testing the differences between soilds and liquids.

Key stage:  KS 2

Curriculum topic:  States of Matter

Curriculum subtopic:  Solids, Liquids and Gases

Difficulty level:

### QUESTION 1 of 10

Look at the coloured liquids in these bottles:

The have a flat surface, which will stay flat if the bottle is tilted. Each liquid takes on the shape of its container - in other words, it fills the container, there are no air gaps.

We can see that these solid marbles do not fill the jar or take its shape, because there are air gaps between the pieces. The surface is not flat. If we tilt the jar, the marbles will move to make another shape, but the surface will always be lumpy, or uneven.

Is the following statement true or false?

Solids take the shape of their container.

true

false

Which statement is true

solids always have a flat surface

liquids always have a flat surface

Peter pours salt into one petri-dish and shower gel into another.

What will happen to the shower gel if he pushes it with his finger?

it will not flow back

it will make bubbles

it will flow back

Peter tests the salt pile in the same way, by pushing his finger into it. What will he notice this time?

it will flow back

it will change colour

it will not flow back

Peter tests other liquids by pushing his finger into a small amount in a petri dish.

He says: "Golden syrup takes a long time to flow back so it can't be a liquid."

Do you think Peter is correct?

yes

no

What is the best way to explain why syrup takes longer to flow back than water?

it is thicker

it is a different colour

it is frozen

Peter looks at the jar of marbles:

Which TWO statements are true?

the marbles take the shape of the jar

there are air gaps between the marbles

the surface is flat

the surface is not flat

Peter takes the marbles out of the jar and replaces them with dry sand.

He says: "Because the pieces of solid sand are small, I cannot see the air gaps, but I know they are there."

Do you agree with Peter?

yes

no

To show that there is air between the grains of sand, what can Peter add to the jar?

more sand

another solid

water

As Peter pours the water into the jar, what will he see on the surface of the sand?

air bubbles

water droplets

nothing

All the air is forced out of the jar of sand because.........

liquids have a flat surface

liquids take the shape of their container

the pieces fit exactly together when the water is added

• Question 1

Is the following statement true or false?

Solids take the shape of their container.

false
• Question 2

Which statement is true

liquids always have a flat surface
EDDIE SAYS
Careful scientists! We can change the surface of liquids by applying a force. Without a force acting on the surface of a liquid it will be flat.
• Question 3

Peter pours salt into one petri-dish and shower gel into another.

What will happen to the shower gel if he pushes it with his finger?

it will flow back
EDDIE SAYS
Liquids flow back if 'pushed'.
• Question 4

Peter tests the salt pile in the same way, by pushing his finger into it. What will he notice this time?

it will not flow back
EDDIE SAYS
The solid pieces of salt will not flow back if they are pushed.
• Question 5

Peter tests other liquids by pushing his finger into a small amount in a petri dish.

He says: "Golden syrup takes a long time to flow back so it can't be a liquid."

Do you think Peter is correct?

no
EDDIE SAYS
Some liquids take longer than others to flow back, but all liquids do flow back.
• Question 6

What is the best way to explain why syrup takes longer to flow back than water?

it is thicker
EDDIE SAYS
Some liquids are thicker than others, which makes them flow more slowly.
• Question 7

Peter looks at the jar of marbles:

Which TWO statements are true?

there are air gaps between the marbles
the surface is not flat
EDDIE SAYS
Solids do not take the shape of their container because of the air gaps between the pieces.
• Question 8

Peter takes the marbles out of the jar and replaces them with dry sand.

He says: "Because the pieces of solid sand are small, I cannot see the air gaps, but I know they are there."

Do you agree with Peter?

yes
EDDIE SAYS
There are very small air gaps between the grains of sand.
• Question 9

To show that there is air between the grains of sand, what can Peter add to the jar?

water
EDDIE SAYS
Water will replace the air gaps between the pieces of sand.
• Question 10

As Peter pours the water into the jar, what will he see on the surface of the sand?

air bubbles
EDDIE SAYS
The air will bubble out of the sand as it is forced out by the liquid.
• Question 11

All the air is forced out of the jar of sand because.........