S3.7.6 For the adult
Levers and turning forces
How can a small child balance a bigger child on a seesaw?
What this chapter teaches
The turning effect of a force is the force times its distance from the pivot. A seesaw balances when both sides match, so a small force far from the pivot can balance a big load close to it.
Three questions to ask
There is no one right wording. Listen for the idea.
- Two caps sit at mark 3 on one side. Where could 3 caps go to balance them?
- Why can a long crowbar lift a stone that you cannot lift by hand?
- Does the heavier side always go down? Why or why not?
After the chapter, the learner can
- Explain how a lever lets a small force lift a big load
- Balance a ruler seesaw with coins at different distances
What they copy into their notebook
Turning effect = force × distance from the pivot. A seesaw balances when both sides are equal. A lever lets a small force far from the pivot balance a big load close in.