Classroom Activity for 5-11
What the Activity is for
To help children describe the world by:
- mixing and matching surfaces to see the effects on grip and slip
- reasoning about the roughnesses of surfaces and the slip or grip forces
What to Prepare
- friction hand puppet pairs: slippy and grippy (grippy can be made of reversed leather, slippy of parachute nylon – see what materials are to hand)
- a varied collection of flat surfaces: carpet tiles, hardboard, linoleum
What Happens During this Activity
Drag a friction hand puppet over a variety of surfaces, and place them in order, according to the slip force experienced. Children might draw up a chart using slip force arrows of different lengths : prefer these to verbal descriptions or numbers.
You might extend this by trying out shoes with different sole designs on different surfaces. Again we'd suggest a report that used slip or grip arrows, depending on the experiment done (remember that slip is all about reducing movement between surfaces, grip is all about preventing movement between surfaces – and so is essential in allowing you to walk).
We'd suggest avoiding anything with wheels, as there are significant slip forces at the bearings (that's why these are often oiled and contain special bits of engineering, such as ball bearings) and these are very hard to analyse.