1.1 The particle model
Summary: Look around you. Can you see things made of wood, plastic, or steel? The different types of stuff that things are made from are called materials. There are millions of materials. Tags: science oxford-science student-book-7 chemistry Created: 2026-05-19 Last Updated: 2026-05-19
After this topic, you will be able to:
- use the particle model to explain why different materials have different properties
- state the factors in the particle model that determine the properties of a substance.
Think back
- Name three materials.
- Give two properties of gold.
- How are the properties of ice and liquid water different?
Key idea All materials are made up of particles. Most materials are made up of more than one type of particle. However, a substance is made up of one type of particle only. The particle model explains some of the properties of materials.
Key words material, particle, mixture, substance, property, particle model
Look around you. Can you see things made of wood, plastic, or steel? The different types of stuff that things are made from are called materials. There are millions of materials.
What is in a material?
Materials are made up of tiny particles. You cannot see the particles because they are too small. Many materials are Mixtures. Wood, milk, and air are mixtures. The bridge in Figure 1 is made from another mixture: steel.
Figure 1Figure 1 The bridge cables (wires) are made from steel. Steel is a mixture of substances.
A Name the tiny things that materials are made up of.
What is a substance?
Some materials are not mixtures. They are just one substance. A substance is made up of one type of material only. It is the same all the way through. Substances include gold, pure water, and oxygen.
Particles in substances
In a substance, every particle is the same. In the air, all oxygen particles are identical. One water particle is the same as all other water particles. One gold particle is the same as all other gold particles. The gold bar in Figure 2 is made up of gold particles only.
Figure 2Gold is a single substance. All of its particles are the same.
But gold particles are not the same as oxygen particles. Oxygen particles are not the same as water particles. Every substance has its own type of particle.
B Explain why gold is a substance.
What gives a substance its properties?
The properties of a substance describe what it looks like and how it behaves. Every substance has its own properties. The particle model describes the movement and arrangement of particles in a substance. You can use the particle model to explain the properties of a substance.
The properties of a substance depend on four things, or factors:
- what its particles are like, for example, their shape and size
- how its particles are arranged and separated
- how its particles move
- how strongly its particles hold together.
For example, gold and silver particles are almost the same size. However, a gold particle is heavier than a silver particle. This explains why a gold ring is heavier than a silver ring of the same size.
In liquid water, particles move over each other. In an ice cube, the particles do not move around. This explains why you can pour water from a glass, but you cannot pour water from an ice cube.
The particles in gold are held together less strongly than the particles in diamond. This explains why gold is easier to scratch than diamond.
C Choose one factor that explains why you can pour water, but you cannot pour ice.
Stretch zone
- Copy and complete the sentences. There are hundreds/millions of materials. Materials are made up of practicals/particles. In a substance, all the particles are the same/different. The particles of different substances are the same/different. The properties of a substance describe its behaviour/particles.
- Name four factors that give a substance its properties.
Stretch zone
- A material is made up of three types of particle. Explain whether the material is a substance, or not.