Particle Model - BBC Bitesize

Seite 1

You can use the idea of particles to explain the properties of solids,

liquids and gases.The strength of bonds between particles is different

in all three states. It explains why solids cannot flow, and why gases

can be compressed.

This Revision Bite covers:

Solids

Liquids

Gases

Flowing

Arrangement and Movement

Solids

Steel, plastic and wood are solids at room temperature. Ice is solid water.

The particles in a solid have the following characteristics:

they are arranged in a regular pattern

they are close together

they are held together by strong forces called bonds

they can vibrate in a fixed position

they cannot move from place to place

The table shows some of the properties of solids and why they are like this.

Property of solids

Why they are like this

They have a fixed shape and cannot flow.

The particles cannot move from place to place

They cannot be compressed or squashed. The particles are close together and have no space to move into.

Liquids

Mercury, lemonade and water are liquids at room temperature.

The particles in a liquid are:

close together

arranged in a random way

The particles in a liquid can:

move around each other

The bonds in a liquid are strong enough to keep the particles

close together, but weak enough to let them move around each other.

The table shows some of the properties of liquids and why they are like this.

Property of liquids

Why they are like this

They flow and take the shape of their container.

The particles can move around each other.

They cannot be compressed or squashed.

The particles are close together and have no space to move into.

Gases

Air, helium and chlorine are gases at room temperature. Water vapour is water as a gas.

The particles in a gas are:

far apart

arranged in a random way

The particles in a gas can:

move quickly in all directions

There are no bonds between the particles in a gas, so they are free to move in any direction.

The table shows some of the properties of gases and why they are like this.

Property of gases

Why they are like this

They flow and completely fill their container.

The particles can move quickly in all directions.

They can be compressed or squashed.

The particles are far apart and have space to move into.

Arrangement and movement

The table summarises the arrangement and movement of the

particles in solids, liquids and gases. It also shows simple diagrams of

the arrangement of the particles that you should be able to draw and

recognise.

Solid

Liquid

Gas

Arrangement of particles

Close together

Regular pattern

Close together

Random arrangement

Far apart

Random arrangement

Movement of particles

Vibrate on the spot

Move around each other

Move quickly in all directions

Diagram

Introduction

Solids

Liqiuds

Gases

Arangement and Movement