## Modelling skydiving

Classroom Activity for 11-14

What the Activity is for

You can build this model with pupils to show how the balance between the different forces leads to different terminal speeds.

What to Prepare

- either one computer, connected to a large display, running the modelling program VnR
- a computer linked to a large display running a modern browser, to share some of the interactive diagrams below

or

- a collection of computers running the modelling program VnR, so that pupils can work in groups of 2 or 3
- a computer linked to a large display running a modern browser, to share some of the interactive diagrams below

What Happens During this Activity

Either you or the pupils build the models shown. The reconstruction given here 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 them 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 parts of the model then allow the pupils to build, or at least be in the driving seat for, the remaining significant linking steps.

You can explore the different facets of the argument using these partial models.

Discuss the evolution of the forces on the skydiver using this interactive diagram:

Using this tool to draw four diagrams to show snapshots in the evolution of forces acting on the skydiver:

Exploring how the drag force varies with velocity: