2. Levers
A lever is a simple machine.
A lever is a rod or a bar that can help lift a load.
3. Levers
Levers are made for lifting things.
People have probably used levers as tools for at
least two hundred thousand years.
By about 17,000 BC people were using levers as
atlatls.
By the time people were living in cities, about
3500 BC they used levers for many more things.
By about 200 BC, scientists like Archimedes were
beginning to figure out why levers worked.
4. Levers
There are three kinds of levers.
The three kinds of levers are named 1st
class, second class, and 3rd class levers.
Levers have a fulcrum a force and a
lode.
