The document discusses the three states of matter - solids, liquids, and gases. It explains the differences between the three states using the particle model, where all substances are made up of particles that are in constant motion. For solids, the particles are tightly packed and can only vibrate. For liquids, the particles are more loosely packed and can move past one another but maintain contact. For gases, the particles are very far apart and move rapidly in all directions.

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Solids, liquids and gases

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States of matter

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What are the substances described in the table?
(Clue: the first letters spell out another word for ‘substance’.)
mercury
aluminium
tin
ethanol
radium
iron
argon
liquid metal
solid used in aircraft
solid used to coat steel cans
intoxicating liquid
solid that rusts
radioactive solid
unreactive gas
solid used by Roman plumbers
Description Substance
lead
Different substances

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At room temperature all substances exist in one of three physical states.
Three states of matter
solid liquid gas

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Solid, liquid or gas?

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The particle model

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The difference between solids, liquids and gases can be explained
by the particle model.
 All substances are made up of
particles.
 The particles are attracted to
each other. Some particles are
attracted strongly to each other
and others weakly.
 The particles move around.
They are described as having
kinetic energy.
 The kinetic energy of the
particles increases with
temperature.
The particle model

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Particles in action

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Solids, liquids and gases

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 has a high density as the particles
are very close together.
 cannot be compressed as there is
very little empty space between
particles.
 has a fixed shape as the particles
are held together tightly by strong
intermolecular forces of attraction.
 cannot diffuse as the particles are
not able to move freely, vibrate
about a fixed point only.
 does not exert any pressure as the
particles cannot move around to
collide with the walls of the
container.
What are the properties of solids?
A solid:

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 has a fairly high density as the particles are close
together enough to touch and slide past one another.
 cannot be compressed as there is very little empty
space between particles.
 takes up the shape of its container
as the particles can move to an
extent– are not in a fixed position.
 can exert some pressure as the
particles are able to move by
sliding past one another and collide
with the sides of the container.
What are the properties of liquids?
A liquid:

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 has a low density as the particles are far apart
 can be compressed as there is space between
particles
 has no fixed shape as the particles move
about rapidly in all directions
 can diffuse as the particles can
move freely in all directions.
 can exert a lot of pressure as the
particles are able to move in all
directions and collide with the sides
of the container.
What are the properties of gases
A gas:

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Solids, liquids and gases: which one?

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Diffusion

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 gas – The state of matter in which particles can freely move, and
in which substances have no fixed volume or shape.
 liquid – The state of matter in which particles are close together
but free to move, and in which substances have a fixed volume
and assume the shape of their container.
 matter – The stuff that everything is made of.
 particle – The smallest unit of matter.
 pressure – The force produced when particles move against a
surface.
 solid – The state of matter in which particles are close together
and cannot move, and in which substances have a fixed shape
and volume.
Glossary

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Anagrams

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Multiple-choice quiz