The 3 types of ionising radiation

P2 Concept 2

Can radiation be stopped?

• recall the three types of ionising radiation emitted by radioactive materials

• distinguish between alpha, beta and gamma radiation by their properties – penetration & ionising ability

Notes…A radiation is ionising if it has enough energy remove electrons from atoms, producing ions.

The ionising ability of the 3 types of radiation can be seen using a spark counter. When atoms in the air is ionised, sparks will jump across.

If ionisation happens to atoms in individual cells, the ions

produced can damage DNA. This mutation can lead to cancer.

Demonstration

Watch carefully and note down your observations.

Demonstration

Watch the demo and think about these questions:

• Which radiation is easily stopped?• Which radiation is the most ionising?

Radiation Source Range in air Stopped by Ionisation

alpha

       

beta

       

gamma

       

Recap

Check learning - Explain

Look at the information you have recorded. 1. Which radiation is most easily stopped?2. Which radiation is most ionising?3. Suggest how your answers might be related.

Applying ideasAmericium-241 emits alpha particles. The fact that it is radioactive would not help doctors detect that it was in a patient’s body. Explain why.

alpha

beta

gamma

alpha

beta

gamma

paper

alpha

beta

gamma

aluminium

alpha

beta

gamma

paper

aluminium lead

Copy the table into the back of your book4

3

2

6

6

4

6

2

1

9 5

6

0Starter Designed by Eugene Brunet; Adapted for PowerPoint by A. Camburn, St George School