◆ Materials · Quarter 1

Does It Keep Its Shape? Does It Keep Its Space?

Two questions. Three answers. That is the whole of the three states of matter.

A stone, a bottle of water and a balloon on the desk. Say nothing yet. 1 min

Three things on the desk

A stone. A bottle of water. A blown-up balloon.
One of them is a solid, one is a liquid, one holds a gas.
Most of you already know which is which.

But how do you know? What is the test?

Take answers. Do not accept 'because it just is'. 4 min

The first question

Take the stone out of your hand and put it on the desk. Same shape.
Pour the water into a cup. New shape — the cup's shape.
Let the balloon go. The gas fills the whole room.

Does it keep its own shape?

Do all three in front of the class. It takes ninety seconds and it is the lesson. 5 min

The second question

The stone takes up the same space wherever it is.
A cup of water is a cup of water in any container. Pour it into a basin and it is still the same amount.
The gas from the balloon spreads out until it fills whatever it is in.

Does it keep its own space?

Space here means volume. Say the word and keep saying it. 5 min

Two questions, three answers

Shape

Solid keeps its shape.<br>Liquid does not.<br>Gas does not.

Space (volume)

Solid keeps its volume.<br>Liquid keeps its volume.<br>Gas does not.

Slide 5 and slide 6 are the wall chart. Point at it and leave it up. 4 min

The curriculum's own words

Solids: definite shape and volume
Liquids: no definite shape; definite volume
Gases: no definite shape or volume

Which of the three is the odd one out, and why?

Liquid — the only one that answers no to the first and yes to the second. 4 min

Now this

Sand.

Solid, liquid, or gas?

Pour it from jar to jar. Let the disagreement run. Do not settle it yet. 5 min

Ask the two questions of sand

Does it keep its shape?

The pile does not — it takes the shape of the jar. But look closer: each grain does.

Does it keep its space?

Yes. A cup of sand is a cup of sand in any container.

So which state is sand?

Solid. Many solids together, behaving like a liquid when poured. 5 min

Why sand fools everybody

Pouring is not one of the two questions.
A powder pours. A pile of rice pours. Salt pours.
Every one of them is a solid.

What was the wrong test we were using?

'Can you pour it?' — a real answer, and not the one the definition uses. 4 min

Matter is anything that…

A stone has mass. Obviously.
Water has mass. You can feel a full bottle.
Air has mass. That is the one nobody believes.

has mass and takes up space

Competency 1 says exactly this. It is not an aside. 3 min

Weighing air

Two identical balloons on a stick, balanced.
Blow one up. Hang them again.
The blown-up one goes down.

What does that prove?

Air has mass. Do this if there is a stick and string; describe it if not. 4 min

When the water boils away

What learners often say

"The water disappeared. It is gone."

What happened

It became a gas and spread into the room. Same water, same matter — no definite shape, no definite volume.

This idea comes back in Quarter 4 as the water cycle. Flag it forward. 4 min

Heat changes the state

Heat a solid and it can become a liquid — ice to water.
Heat a liquid and it can become a gas — water to steam.
Cool a gas and it can become a liquid again — the drops on a cold glass.
The material does not change. Only the state does.

Competency 6. One sentence today; a full week in Week 6. 4 min

Measuring the space

Volume is measured in millilitres and litres.
Read a cylinder with your eye level with the surface.
Read the bottom of the curve.

Why does it matter where your eye is?

Because the same water gives two different readings. Show it. 4 min

One sentence to leave with

Two questions, asked in order, name every state of matter.

Say it together. It is on the worksheet and on the wall chart. 2 min