Teaching and learning about ionising radiation

Building up an understanding of something that is not visible

Teaching and learning about ionising radiation takes us into one of those physics contexts where the phenomenon being studied, in this case the radiation, is not directly visible. The challenge for the learner (and for the teacher) is therefore to build up a picture of the similarities and differences between the types of radiation in terms of their properties (what they do) and origins (where they come from). Here we'll consider teaching and learning challenges relating to the properties of ionising radiation before moving on to the origins/sources of ionising radiation in episode 05.

A further challenge for teaching and learning in this area of physics follows from the fact that ideas about ionising radiation and radioactivity are quite commonplace in everyday situations. Thus students are likely to have heard or read about:

• Debates relating to nuclear power, particularly in light of the Fukushima Power Station disaster.
• The terrible damage from nuclear weapons.
• The use of radioactive materials in medical contexts.

Such existing knowledge is good because it provides a starting point for subsequent teaching and learning to build upon. At the same time, the teacher needs to be aware that these common-sense ideas are often at odds with the physics point of view and therefore need to be challenged directly if a deep understanding is to be the outcome:

Teacher: So today we're going to start a new topic: radioactivity. Who can tell me anything about radioactivity?

Jade: It's dangerous. Look at that Japanese accident!

Teacher: Well, in some situations it is, in some it isn't. We need to find out!