The document discusses the three states of matter - solid, liquid, and gas. It introduces kinetic theory, which explains that matter is made up of particles that are constantly in motion. The way these particles are arranged determines the three states of matter and their properties. Solids have particles that are close together and do not move much. Liquids have particles close together but able to move and change position. Gases have particles far apart that move freely throughout their container.

1. 3. THE STATES OF MATTER

2. NEXT
This unit starts with an introduction to the three states
of matter: solid, liquid and gas. To explain these three states and
their characteristics, we need to understand that matter is
discontinuous. In other words, it is made up of small particles.
You'll have an introduction to kinetic theory. Scientists
use this theory to explain what matter is like and why it occurs in
such different forms.
Then, we'll apply kinetic theory to examining the
various changes of state and the changes in the general
properties of matter that result.
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3. IN THIS UNIT YOU WILL FIND
OUT THE ANSWER TO THESE:
 What is matter?
 What are the three states of matter?
 Can a substance exist in all three states? Can you think
of an example?
 What is a change of state?
 What is melting?
 What is condensation?
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4. KEY WORDS
 MATTER: physical substance that everything in the universe consists of.
 STATE: specific physical form (solid, liquid or gas) that matter has and
that can change.
 SUBSTANCE: specific type of solid, liquid or gas.
 MELTING: when a solid becomes a liquid by heating .
 CONDENSATION: when a gas becomes a liquid by cooling.
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5. 1. THE THREE STATES OF MATTER
KEY WORDS Matter has three main forms
called states. The three states are: solid,
 MASS: amount of matter that an
liquid and gas.
 Solids have a definite mass, shape
object contains. and volume.
 SHAPE: external form of something.  Liquids have a definite mass and
volume, but nota definite shape.
 CONTAINER: object (such as a box They take the shape of the
container they are in.
or bottle) used to store things.
 Gases have a definite mass, but not
 DEFINITE: fixed and specific. a definite shape or volume. Gases
take the shape of the container
they are in, and occupy its total
BACK NEXT volume.
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6. SOLIDS LIQUIDS GASES
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7. KINETIC THEORY
Scientists believe that matter is
composed of very small particles. These
KEY WORDS
particles are so small that they cannot be seen  Particle: very small piece of
matter.
even with the most powerful microscopes.
 Supposition: something you
Scientists also believe that these
think is true but that you can't
particles are constantly moving. prove.
These suppositions are the basis for the  Arranged: put in a specific
Kinetic theory of partides. According to this order.
theory, the way in which the particles in  Far apart: separated by a large
matter are arranged determines the three
distance.
possible states and also the properties of each
 aggregation: when many
separate things are close to each
state.
other or come together.
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8. ACTIVITIES
1. Listen and say what state the substance is usually found in.
Example: salt: solid. Answer
2. Put the words in order to make questions. Listen and check.
Ask and answer the questions with a partner.
a) the properties / What / state of matter / are / of each /?
b) of matter / the general properties / What / are /?
c) in all three states / is often found / natural substance / What /?
d) how / the kinetic theory, / is matter arranged / According to /?
e) take the shape / can / of the container they are in / liquids / Why /?
f) and / where / the fourth state of matter / What / is it usually found
/ is /? Answer
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9. BACK ANSWERS
a) Salt: a) What are the properties of each state of matter? All the states of matter
Solid
have three properties; mass, shape and volume.
b) Milk.
Liquid b) What are the general properties of matter? The most common properties
c) Chocolate of matter are mass and volume, from which density is obtained.
Solid
c) What natural substance is often found in all three states? Water. Ice is
d) Oxygen
water in a solid state, water is the same substance in a liquid state and
Gas
e) Paper water vapour is the gas state. Clouds are formed of drops of liquid water or
Solid by snowflakes in suspension but not by water vapour, as this is invisible.
f) Orange juice d) According to kinetic theory how is matter arranged? According to kinetic
Liquid
theory, matter is formed of constantly moving particles.
g) Air
Gas e} Why can liquids take the shape of the container they are in? Liquids can
h) Hydrogen adapt to the form of the container they are in because their particles are not
Gas as close together as in solids and they can move and change position relative
i) Seawater
to each other.. Next
liquid
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10. f) What is the fourth state of matter and where is it usually
found? The fourth state of matter is plasma. Most matter in the
universe exists as plasma, as the high temperatures needed to
form it occur there: but plasma is rarely found on Earth as it is
not hot enough.
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11. SOLIDS
In solids the particles are
very close together. They may
vibrate a little but they do not
move: they have a fixed position.
In some solids the particles are
arranged more regularly, in
special geometric shapes.
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12. LIQUIDS
In liquids the
particles are close together
(but not as close as in
solids), and they can move
and change position
relative to each other. This
means liquids can flow and
take any shape.
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13. GASES
In gases the
particles are far apart from
each other and they move
freely and very quickly.
They occupy all
the space available and do
not have a definite shape or
volume.
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