Changes of state
6/11/20
What are the three states of matter?
• Solids
• Liquids
• Gases
Solids
Solids are easily controlled
Cannot easily be compressed (squeezed)
Cannot flow (or diffuse)
Can be cut
Have a definite shape
and volume
Liquids
Quite difficult to control
Cannot easily be compressed (squeezed)
Can flow and take the shape of their
containers
Cannot be cut
Have a definite volume but
different shapes
Gases
Hard to control
Can easily be compressed
(squeezed)
Flow easily spreading into open
spaces
Cannot be cut
Do not have definite
volume or shape
Changing States
When a solid is heated it melts to become a liquid.
When a liquid is heated it boils
and becomes a gas i.e. Boiling.
If a liquid becomes a gas
without bubbling we call it
evaporation.
Changing State
When a liquid is cooled until it becomes a solid
we say it freezes.
When a gas is cooled till it becomes a liquid we
say it condenses.
Changing States of Matter
Melting
Evaporation
Liquid
Solid
Freezing
Gas
Condensation
Changing States of Matter
Melting
Evaporation
Liquid
Solid
Freezing
Copy me
down!
Gas
Condensation
3 minutes
Changing States of Matter
What is
melting
point?
Melting
Evaporation
Liquid
Solid
Freezing
Gas
Condensation
Changing States of Matter
Melting
What is
boiling
point?
Evaporation
Liquid
Solid
Freezing
Gas
Condensation
Finish these sentences.....
1. Melting point is the temperature where.......
2. Boiling point is the temperature where........
Melting
Evaporation
Liquid
Solid
Freezing
Gas
Condensation
4 minutes
Changing States of Matter
-The Particles
Changing States of Matter
-The Particles
Increasing vibrations & movement
Changing States of Matter
-The Particles
As more energy is
added – what happens
to the space between
the particles?
Increasing vibrations & movement
Changing States of Matter
-The Particles
It increases! That’s
why the substances
become less dense.
Increasing vibrations & movement
Changing States of Matter
-The Particles
There is more space
between particles, so
less particles per unit
area.
Increasing vibrations & movement
Changing States of Matter
-The Particles
For example, in 1cm3
of substance, there
would be far more
particles in....
Increasing vibrations & movement
Changing States of Matter
-The Particles
A solid compared to a
gas, even if it’s the
same substance!
(e.g water)
Increasing vibrations & movement
Changes of state
9/11/20
Changing States of Matter
Melting
Evaporation
Liquid
Solid
Freezing
Subliming
Gas
Condensation
Changing States-The Particles
Explain in terms of the energy of particles
why:
1. Solids melt
2. Liquids evaporate
3. Gases condense
4. Liquids freeze
Remember! When particles
gain energy they start to
vibrate more and more and
more until....?
Extension: Give an example of each.
In your book – draw a 3 x 3 table
Temperature
Heat
oC
Joules
Energy
Thermal
Hot
Metals
Wood
Conductor
Insulator
Well
Badly
Particles
Vibrate
Saucepan
Solid
Liquid
Gas
Condense
Evaporate
Freeze
Melt
Boiling Point