Matter

What is matter?

Matter is anything that has mass and volume (takes up space).

There are three physical states of matter. Solid, liquid and gas.

Solid ice Liquid water Iodine gas

Solids retain their shape. They have a fixed volume.

Liquids take up the shape of their container. They have a fixed volume.

Gases fill their container. They have a variable volume. This means the volume changes. It depends upon the volume of the container.

Experiments - physical changes

Experiments and ideas: Physical changes

  1. Can the three states of water exist together in a test tube?
  2. Is steam different from water vapour?
  3. How do clouds form?
  4. Water passing through a beaker?
  5. Examine your breath! 
  6. Boil water in a paper cup.
  7. How to pick up an ice cube with string and salt?
  8. To sublime or not to sublime! That is the question.
  9. Does water boil past 100ºC?
  10. Observe a candle burn
  11. How to make a heat pack. (Sodium acetate)
     

Physical change

Physical changes

Matter exists in one of three physical states - solid, liquid or gas.

In a physical change matter changes state from one physical state to another.

For example when an ice cube melts it changes from the solid state to the liquid state.

Physical changes are easily reversible. In the melted ice cube is put back into the freezer it will change back into a solid.

Key points:

  • Matter exists in three physical states - solid, liquid and gas.
  • Matter can change from one physical state to another.
  • The physical changes of state are easily reversible
  • Energy is absorbed or given off during physical changes of state.

What are the physical changes of matter?

  • A solid changing to a liquid it is called melting or fusion.
  • A liquid changing to a gas is called evaporation.
  • A gas changing to a liquid is called condensation.
  • A liquid changing to a solid is called solidification or freezing.
  • A solid changing to a gas is called sublimation.  

Examples of physical changes.

Physical change Example
 Sublimation Dry ice change from a solid to a liquid
 Melting or fusion  An ice cube melting
 Condensation  The formation of dew on grass in the morning
 Evaporation  A puddle disappearing on a hot day
 Solidification or freezing  The formation of hail stones

 

The particle theory

The particle theory of matter

The particle theory states

  • All matter is made up of particles.
  • All particles are attracted to one another.
  • All particles are constantly moving.
  • Temperature is a measure of the average speed of the particles.

This theory can be used to help explain some of the properties of matter.
 

The Properties of Solids, Liquids and Gases and the Particle Theory

  Solid Liquid Gas
Properties
  • fixed shape
  • fixed volume
  • cannot be compressed
  • no diffusion*
  • variable shape
  • fixed volume
  • cannot be compressed
  • slow diffusion*
 variable shape
variable volume
can be compressed
rapid diffusion*
Beaker  Beaker with solid  Beaker with liquid  Beaker with gas

Conical
flask

  Conical flask with solid  Conical flask with liquid  Conical flask with gas

Particle
theory

The particles are close together and are vibrating in fixed positions.

 The particles are close together and are moving slowly over one another. The particles are far apart and are moving quickly past one another.

 * Diffusion is the random movement of particles from an area of high concentration to an area of low concentration.