Solids, Liquids and Gases
Solids, Liquids and Gases
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Solids, Liquids and Gases
Open with familiar objects in the classroom so pupils connect the title to things they already know: table, water bottle, air in a balloon.
Glossary
matter - anything that takes up space and has mass
state of matter - the form a material is in, such as solid, liquid or gas
solid - a state of matter that keeps its own shape
liquid - a state of matter that flows and takes the shape of its container
gas - a state of matter that spreads out to fill a space
particle - a tiny piece of matter in the particle model
volume - the amount of space something takes up
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What?
I can identify solids, liquids and gases and describe their properties.
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What words come to mind when you hear solids, liquids and gases?
Use this to surface prior knowledge and everyday examples such as ice, water, air, shape, flow or particles.
What is matter?
Everything around us is made of matter.
Matter takes up space and has mass.
The three main states of matter we learn about are:
solids
liquids
gases
Keep this simple and concrete. At this age, 'mass' can be explained as how much matter is in something.
Three states of matter
The same material can be in different states.
For example, water can be:
ice — a solid
water — a liquid
water vapour — a gas
This slide helps pupils see that state is about how particles are arranged and behave, not about what the substance is called.
How particles behave
Scientists use a particle model to explain matter.
In a solid, particles are packed closely and stay in place.
In a liquid, particles are close together but can move past each other.
In a gas, particles are far apart and move freely.
These differences give each state its properties.
You can mime the particle movement with your hands or bodies: still and packed for solid, sliding for liquid, spread out for gas.
Scientific diagram: particles
A particle diagram shows:
solid: particles in neat, tight rows
liquid: particles close together, not in rows
gas: particles spread far apart
Although the stock image search may return a teaching-style diagram, explain clearly that particles are too tiny to see with our eyes.
Which state has particles packed tightly and stays in shape?
Liquid
Gas
Solid
Steam
Checks the particle model and the key property of solids. 'Steam' is included as a common confusion with gases.
Complete the particle ideas
Everything around us is made of matter. In a solid, particles are packed closely. In a liquid, particles are close together but can move past each other. In a gas, particles are far apart.
Echoes the wording from the matter and particle-model slides so pupils recall the key scientific terms.
Properties of solids
Solids have these properties:
they keep their own shape
they have a fixed volume
they do not flow like liquids
their particles are packed tightly
Examples: rock, spoon, book, brick
Fixed volume means the amount of space the solid takes up stays the same unless it is cut, squashed or changed in another way.
Examples of solids
A solid can be big or small, hard or soft.
It is still a solid if it keeps its shape.
Examples:
pencil
chair
toy block
apple
Pupils sometimes think only hard objects are solids. Remind them that a soft rubber or sponge is still a solid if it keeps its shape.
Which object is a solid even though it can feel soft?
Milk
Balloon air
Sponge
Steam
Targets the misconception mentioned in the solids examples: not all solids are hard.
How can a soft object still be a solid?
Look for the idea that a solid keeps its own shape, even if it is soft or squashy. Accept simple examples such as sponge, rubber or pillow if pupils explain the shape idea.
Properties of liquids
Liquids have these properties:
they flow
they do not keep their own shape
they take the shape of the container
they have a fixed volume
their particles stay close but move around
A liquid changes shape when poured, but the amount of liquid stays the same.
Examples of liquids
Liquids can be poured.
Examples:
water
milk
juice
cooking oil
If useful, contrast liquids with powders like sand or sugar, which can be poured but are made of tiny solids.
What happens to a liquid in a cup?
Fills all space
Keeps its shape
Takes cup shape
Becomes a solid
Checks the key liquid idea: it changes shape to match its container but keeps the same volume.
Complete the liquid facts
Liquids flow and do not keep their own shape. They take the shape of the container, but they still have a fixed volume.
All four blanks are load-bearing vocabulary from the liquids slides.
Properties of gases
Gases have these properties:
they spread out to fill a space
they do not have their own shape
they do not have a fixed volume
they can often be squashed into a smaller space
their particles are far apart and move quickly
Use air in a syringe or balloon as a familiar example of a gas taking up space.
Examples of gases
We cannot usually see gases, but they are all around us.
Examples:
air
oxygen
carbon dioxide
water vapour
Clarify that 'steam' from a kettle is mostly tiny water droplets we can see; the water vapour itself is invisible.
Which property belongs to a gas?
Fixed shape
Fixed volume
Flows only downhill
Fills a space
Focuses on the main difference between gases and liquids: gases spread out to fill the whole space.
Complete the gas facts
Gases spread out to fill a space. They do not have their own shape and do not have a fixed volume. Their particles are far apart and move quickly.
Reinforces the taught phrasing from the gases slide.
Compare the three states
Solid - keeps its shape; fixed volume
Liquid - changes shape; fixed volume
Gas - changes shape; no fixed volume
All three are forms of matter, but their particles are arranged differently.
This is the key comparison slide. Pause on shape and volume because those are the main sorting rules pupils will use.
How to identify each state
Ask about space
Does it fill the whole space?
If it fills the container, it is a gas.
If it only takes the shape of the bottom part, it is a liquid.
Does it keep its own shape?
If yes, it is likely a solid.
If no, it could be a liquid or a gas.
Ask about shape
This gives pupils a simple sorting method rooted in scientific properties rather than guessing from appearance.
Identify solids, liquids and gases
Use what you know about shape, volume and flow.
Solids: table, coin, shoe, crayon
Liquids: rain, paint, shampoo, soup
Gases: air, helium, water vapour, oxygen
This matches the teacher's request for a page where children identify examples they know, while keeping it content-only. The later interaction pass can turn this into a sorting task.
Which state fills the whole container?
Solid
Liquid
Gas
Ice
Uses the sorting rule from the compare and identify slides.
Which clue helps you most when identifying a state?
Shape
Volume
Flow
Space filled
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