States of matter

 

 

Solids

Some examples of solid materials are paper, bricks, wood, metal and ice.

The particles in a solid are held together by strong forces that keep them in fixed places, in a regular pattern. The particles are very close and only shake around these fixed places. They cannot move around.

 

Solids have a fixed shape and do not flow like liquids or gases because the particles are in fixed places. Solids cannot usually be squeezed because there is hardly any space between the particles. The particles in a solid should be drawn as close together, in neat, ordered rows.

 

 

A particle model of a solid (Note: Particles are all touching)

Liquids

Water, oil and fruit juice are some common examples of liquids. The particles in a liquid are not in fixed places because the forces between them are weaker than in a solid.
The particles in a liquid are still close together, but they are randomly arranged. They can vibrate and also move around.

Liquids do not have a fixed shape and can flow because the particles can move and vibrate. This means that a liquid will fit the shape of the bottom of its container. Like a solid, liquids cannot usually be squeezed because there is hardly any space between the particles.

The particles in a liquid should be drawn as close together with very few gaps, in a random pattern.

 

 

A particle model of a liquid (Note: The particles in a liquid are closely spaced and randomly arranged.)

 

Gases

Some examples of gases are:

 

• the air we breathe
• the helium that fills balloons.
• the steam that comes out when a kettle boils

 

The particles in a gas are so energetic that they can break free from the forces that try to keep them together. This makes the particles in a gas spread out and move in any direction. The particles in a gas do not shake - they move fast in straight lines, randomly. This means they can hit each other and the walls of any container they are in.

 

Gases do not have a fixed shape because the particles can move freely in all directions. They can fill up their container and flow to take its shape. Gases can also be squeezed easily because there is a lot of space between the particles.

 

The particles in a gas should be drawn as far apart and in a random pattern.

 

A particle model of a gas (Note: The particles in a gas are widely spaced and randomly arranged.)

 

Below is a table that compares the three states of matter.

 

State	Solid	Liquid	Gas
Arrangement of particles	Regular arrangement	Random arrangement	Random arrangement
Movement of particles	Vibrate around a fixed position	Move around each other	Moves quickly in all directions
Closeness of particles	Very close together	Close together with no regular arrangement	Very spaced out

 

Summary:

 

• There are three states of matter that substances can be in - solid, liquid and gas.
• The forces between the particles that make up substances are different in each state of matter.
• The properties of solids, liquids and gases depend on how the particles are arranged, how they move and how much space they have.