Book 26, Question 132
How can you build a gadget using a lever or pulley?
Levers and pulleys are simple machines that make work easier.
A lever, like a ruler resting on a pencil, can lift a small weight by pushing down on the other end. A pulley changes the direction of a pull so you can lift by pulling down. You can build a mini crane that lifts a small bucket using a spool, string, and a stick.