1. Particle theory Aims: 1. To know the three states of matter
2. To be able to relate the particle theory
to changes of state
3. To know the terms used to define each
change of state

2. Matter is made up of anything that takes up space and has mass.
Does air take up
space?
Does air have
mass?

3. There are three states of matter.
Solids
Liquids
Gases

5. Particle Theory All matter is made of tiny particles
Particles are called molecules or atoms
The particles are attracted to each other
The particles are always in motion
The amount of motion of particles depends on the amount of (heat) energy

6. The Three States of Matter
Matter can be in one of three “states”. The three states of matter are SOLIDS, LIQUIDS and GASES.
What are their properties?
Solid
Liquid
Gas
Very difficult to squash, can’t be poured
Difficult to squash, can be poured
Easy to squash, can be poured

7. Solids
Have a definite shape
Have a definite volume
Particles are packed tightly together
Particles cannot move freely

8. Liquids Have no fixed shape Have a definite volume
Particles are packed loosely together
Particles can move a little

9. Gases Have no definite shape Have no definite volume
`Particles are far apart
Particles move freely

10. Activity: Copy out the three states of matter leaving a gap beneath each.
GAS
SOLID
LIQUID

11. Words to use – strong, close, vibrate, fixed
Particle theory
Particle theory is all about explaining the properties of solids, liquids and gases by looking at what the particles do.
SOLIDS
In a solid the particles ______ around a _____ position. There is a ______ force of attraction between each particle and they are very _____ together
vibrate
fixed
strong
close
Words to use – strong, close, vibrate, fixed

12. Words – fixed, collide, any, quickly, close, very, solids
LIQUIDS
In a liquid the particles are _____ together but can move in ____ direction. They won’t keep a _____ shape like _____ do.
close
any
fixed
solids
GASES
In a gas the particles are far apart and move _____ in all directions. They often ______ with each other and because they are far apart they can be easily _______.
quickly
collide
squashed
Words – fixed, collide, any, quickly, close, very, solids

13. Changes of State Liquid Solid Gas melting evaporating freezing
condensing

14. Changes of State
Changes of state occur when one state of matter (i.e. solid, liquid or gas) is changed into another…
2) If even more energy is supplied to the liquid the bonds will be completely broken and the liquid will turn into a…
1) If enough energy is supplied to a solid the particles will break free from their fixed positions and the solid will become a…
GAS
LIQUID
3) A gas can be turned straight back into a solid, but this is very rare

15. Changes of State
What are these processes called? Choose from freezing, boiling, melting, condensing
Boiling
Melting
Freezing
Condensing

16. Some definitions… Melting A change of state – solid to liquid
A change of state – liquid to gas
A change of state – gas to liquid
A change of state – liquid to solid
Evaporation
Condensing
Freezing

17. Quiz
Solid, liquid and gas
Name the 3 states of matter
Which of the 3 states can’t be poured?
Which of the 3 states is water vapour?
Which of the 3 states will match the shape of any container?
Which of the 3 states is most easily compressed?
What is the name of the change of state for when a liquid turns into a gas?
What is the name for when a gas turns back into a liquid?
Solid
gas
Gas & liquid
gas
boiling
Condensation

18. Activity: Pretending to be particles
Thunderbolt kids