# 2. Modelling atoms

Difficult ideas can often be helpfully illustrated using a role play. This can make something very abstract feel concrete and can help the students to understand. The danger, of course, is that an inaccurate model can introduce more misconceptions and difficulties at a later stage.

Resource 3 is about modelling in science. When you are using a role play to represent an idea, you should always get your students to explain what they are doing. By identifying the strengths and weaknesses of the model, you will also add to their understanding. The teacher in Case study 2 has a really big class. This can be discouraging and may put teachers off doing activities like role play. But she has come up with a plan of how to make it work. You could use her idea for other activities that would be difficult to do with a large number of students. Activity 2 describes a role play that your class should enjoy. You could set it up like a game, with some students acting out a process, and some guessing which process it is. This will make everyone concentrate and think about the ideas.

## Case study 2: Working with a large class to do a role play

Mrs Lomwe had 80 students in her class. She was keen to do a role play to help them understand ideas about particles but was not sure how to organise so many students for a role play. She talked to some of the other teachers and between them they made a plan.

Mrs Lowme was fortunate to have some students who were natural leaders. She selected eight students and asked them to stay behind after school one day. She explained the purpose of the role play and that she wanted them to act as group leaders. She did the whole activity with the group of eight and showed them exactly what she wanted them to do. The idea was to get the students to behave as particles and to act out processes such as ‘condensation’ and ‘evaporation’.

The next day, she split the class into four groups, with two of the leaders in each group. Two groups stayed in the classroom, but two of the groups went outside. The leaders had to split their group in half. One half acted out one of the processes while the others had to guess which one it was. Then they swapped over. The students were encouraged to praise or criticise each others’ ‘shows’. If they thought it was good they had to explain why. If they thought it could be improved, they had to explain how. Many thought that the group acting out a liquid could have improved their performance if one or two of the students had left the group, showing that all liquids evaporate. But they liked the way the ‘particles’ kept bumping into each other.

## Activity 2: Helping students model atoms

Divide your class into three groups. Draw a large square on the floor with chalk. Ask one group to act out being a solid. Get the other students to say two good things about the performance and one thing that could be improved. Repeat for a liquid and a gas, so each group gets a turn.

Then give each group the name of a process such as evaporation, condensation, freezing, melting or dissolving. Ask them to act out their process. The other groups have to guess which process it is. They have to explain why they think it is that process and say what is good about the performance. Research shows that students find it difficult to explain these processes in terms of the particles. This activity will help your students to understand the processes.

1. Probing understanding

3. Making revision fun