A lever allows you to lift heavy objects using less force by acting as a mechanical advantage, with your arm acting as the lever itself when picking up heavy objects. Scientists like Archimedes began studying levers around 200 BC to understand why they worked. A screw is also a type of lever that provides mechanical advantage.

2.  Whenever you pick up anything heavy
your arm bone acts as the lever itself.

3.  By about 200 BC scientists like
Archimedes were beginning to figure out
why levers worked.

4. A screw is a lever.