States of matter

Understanding the properties of solids, liquids and gases, and how particles are arranged in each state

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1
Put these states of matter in order from most tightly packed particles to least tightly packed. Put these in order: Gas, Liquid, Solid
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2
Match each state of matter to its properties. Match each item on the left to one on the right. Left: Solid, Liquid, Gas Right: Fixed shape and fixed volume, No fixed shape but has a fixed volume, No fixed shape and no fixed volume
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3
Which of these is a gas? A) Water vapour B) Ice C) Juice D) Sand
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4
True or false? Liquids can be poured and they take the shape of their container. A) True B) False
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5
Why can gases be compressed (squashed) but solids cannot? A) Because gas particles have lots of space between them that can be reduced B) Because gas particles are smaller than solid particles C) Because gas particles are lighter D) Because solid particles are heavier
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6
Match each example to its state of matter. Match each item on the left to one on the right. Left: Oxygen in the air, Milk, A diamond, Steam from a kettle Right: Gas, Liquid, Solid, Gas
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7
True or false? Sand is a liquid because you can pour it. A) True B) False
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8
Order these by how quickly their particles move, from slowest to fastest. Put these in order: Particles in ice, Particles in steam, Particles in water
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9
A balloon is blown up and sealed. Why does it keep its round shape? A) Gas particles inside push outward against the balloon in all directions B) The gas particles are stuck to the inside of the balloon C) The balloon is a solid so it keeps its shape D) Air is not really inside the balloon
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10
Is toothpaste a solid, a liquid, or something in between? Explain your reasoning. A) It has properties of both solids and liquids - it holds its shape but can flow when squeezed B) It is definitely a liquid because it comes from a tube C) It is definitely a solid because it holds its shape on the brush D) It is a gas because it contains air bubbles
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Answer key

States of matter · for parents and teachers

1
Solid, Liquid, Gas
In solids, particles are tightly packed in a fixed arrangement. In liquids, they are close but can move past each other. In gases, they are spread far apart.
2
Solid → Fixed shape and fixed volume; Liquid → No fixed shape but has a fixed volume; Gas → No fixed shape and no fixed volume
Solids keep their shape. Liquids take the shape of their container but have a definite volume. Gases spread out to fill any container completely.
3
Water vapour
Water vapour is water in its gas state - it is invisible and fills the air. Ice is solid water. Juice is a liquid. Sand is made of tiny solid particles.
4
True
True. Liquids flow and take the shape of their container because their particles can move past each other, but they stay close together.
5
Because gas particles have lots of space between them that can be reduced
Gas particles are spread far apart with lots of empty space between them. When you compress a gas, you push the particles closer together. Solid particles are already packed tightly with no space to reduce.
6
Oxygen in the air → Gas; Milk → Liquid; A diamond → Solid; Steam from a kettle → Gas
Oxygen and steam are gases (they spread to fill spaces). Milk is a liquid (it flows and takes the container's shape). A diamond is a solid (fixed shape).
7
False
False. Sand is made of tiny solid particles. Although you can pour it, each grain keeps its own shape. Pouring is not what defines a liquid - having particles that flow past each other does.
8
Particles in ice, Particles in water, Particles in steam
Particles in solids vibrate slowly in fixed positions. Liquid particles move faster and slide past each other. Gas particles move very quickly in all directions.
9
Gas particles inside push outward against the balloon in all directions
The gas particles inside the balloon move quickly in all directions, hitting the balloon walls and pushing outward (gas pressure). This is what inflates and maintains the balloon's shape.
10
It has properties of both solids and liquids - it holds its shape but can flow when squeezed
Toothpaste behaves like both: it holds its shape (solid-like) but flows when force is applied (liquid-like). Scientists call this a non-Newtonian substance.