Modelling levers

What the Activity is for

You can use this model to bring out and keep to the fore the central qualitative relationships between the forces, lengths and distances related to levers.

What to Prepare

• Either one computer, connected to a large display, running the modelling program VnR
• Or a collection of computers running the modelling program VnR, so that pupils can work in groups of two or three
• A plan to allow pupils to build models like in the example (see below)

What Happens During this Activity

Either you or the pupils build the models shown. The reconstruction given gives the salient points, but you need not follow the sequence slavishly.

In particular, you can adapt the starting points, perhaps giving the pupils the variables and asking them to connect them together. They could then move on to a larger range of variables, with a different goal set by you.

In any case it is wise to set the pupils mileposts along the way to the final destination, and to get them to check their models as they go.

If you choose to build the model up with the class, you may find it a good strategy to have a volunteer to do the keyboarding and pointer driving for you, allowing you to concentrate on running the discussion with the class.

A good way to work is for you to build up one of the models, then allow the pupils to build, or at least be in the driving seat for, one or both of the others.