Some mechanisms, including levers, pulleys and gears, allow a smaller force to have a greater effect.
A pulley is simply a collection of one or more wheels over which you loop a rope to make it easier to lift things.
The more wheels you have, and the more times you loop the rope around them, the more you can lift.
We have been making our own pulleys and recording how much force is needed to lift a load.
Some children even constructed pulley systems outside at break time.
