Physical and chemical properties - BBC Bitesize (2024)

• All substances have properties. These describe how a substance looks and behaves.
• There are two types of properties: physical and chemical.

Watch this video about how physical and chemical properties affect which materials we use in everyday life.

While you're watching, try to look out for properties which are opposite to each other.

A is something that describes how a substance behaves. There are 2 types of properties:

• - chemical changes happen when chemical reactions occur. They involve the formation of new chemical elements or compounds.

• - in a physical change, a substance simply changes physical state. For example, from a solid to a liquid.

Did you know?

Most cooking pans are made from aluminium and steel. This is because a property of aluminium and steel is that they are excellent of heat. This means that thermal energy from the stove transfers efficiently into the food we cook.

Physical properties can be seen and can usually be measured quite easily in an experiment. Here are some examples:

• By applying force to an object you can observe it's physical properties. If something is the object may snap, or if it is the object will bend.
• By observing a solid's , or a liquid's these physical properties can be measured.

Chemical changes happen when occur. However, the properties cannot be learnt just by looking at, touching or taking a simple measurement of the substance.

Examples of how we can measure chemical properties include:

• Observing how elements react with air.

For example, the Group 1 elements react with moist air. They are stored in oil to stop air and water vapour coming into contact with them. Moist air reacts with potassium to form potassium oxide. This creates a layer over the surface of the metal.

Find out more about the Group 1 elements in this guide.

• We could measure the pH of a liquid.

The pH scale shows how acidic a substance is. It can be measured using a pH meter which gives a numerical value. pH can be also be measured using an indicator and comparing the colour with a comparison chart.

Find out more about the pH scale in this guide.