1 What do students find difficult about electricity?
Apart from the abstract nature of the concepts involved, it is possible that students have developed misunderstandings about electricity from everyday experience. For example, younger students see a piece of electrical equipment connected to the electricity supply by a single cable and plug, but have to learn that there must be a complete circuit inside this for the device to work.
Research has shown that some misunderstandings of electrical circuits are common even among older students. These misunderstandings include the examples in Table 1.
|Student idea||Accepted science idea|
|The battery provides current or charge||The battery provides the potential difference needed to move charge round the circuit|
|The current is ‘used up’ by the components in a circuit||The current is the same throughout a series circuit. The best way to challenge these misunderstandings is to provide evidence to the contrary by showing that ammeter readings are the same on either side of a lamp, but some students may still hold on to this idea|
Some students may also find it difficult to distinguish between voltage and current, or between current and energy.
For some students, it is also difficult to relate neat, deceptively simple circuit diagrams to the array of wires and components that make up some of the circuits that they will work with. There is a lot to take in when looking at the construction of many circuits. Your students may find it difficult to pick out the important detail unless you explain the circuit, asking them to tell you what is connected where, whether it is connected in series or in parallel, and so on.
Case Study 1: Difficulties faced when learning about electricity
At a recent training session, Miss Joshi learnt about some of the things that many students find difficult or confusing when learning about electricity.
In the training session we discussed some examples of the problems that many students have in learning about electricity and where we might encounter some of these in lessons.
We started with ideas about what a battery does, but it soon led into other areas of confusion. I hadn’t really thought about it before, but as we talked, I realised that I had seen this problem in some of my students that I had taught. They thought the battery was providing the charge, and needed to keep doing this because the charge was ‘used up’ as it went through components in the circuit. If they didn’t believe that the charge was there already and the battery provided the potential difference to make the charge move, then how could closing a switch make everything come on instantly? The idea of charge drifting along at millimetres a second doesn’t make sense unless the charge is already there …
As we talked about where some of the difficulties might occur in the Class X electricity lessons, I realised that having some of these misunderstanding and difficulties could cause problems again and again. I would need to take account of the possible difficulties when planning my lessons.
Pause for thought
Activity 1: Planning how to teach students about electricity
This activity will help you to plan for teaching about electricity by considering what kinds of difficulties your students may encounter in particular lessons.
Look at each section of Chapter 12 in the Class X textbook and identify the key points and sources of difficulty in each section. Use Table 2 to record your ideas. (You will look at some possible strategies for countering these difficulties in a later activity.)
When you have finished, compare your notes to Resource 1,which includes some possible comments.
|Section||Activity||Key teaching points/what do I want students to learn from activity and related text?||Sources of difficulty?|
Current (measured in amperes) is the flow of charge (measured in coulombs) per second
Current measured by an ammeter. Conventional current flow is from + to –
Current and electron drift through a conductor. Current is instantaneous but drift speed is about 1mm s–1
Charge is not something that is visible.
Reconciling slow drift of electrons with instantaneous current.