"Give me a place to stand, and I will move the earth" -- Archimedes
A Class 1 lever is a lever where the force and weight are on opposite sides of the pivot.
Example:
Force Weight
\/ \/
_______________________
(_______________________)
/^\
Pivot
Class 1 levers are useful for gaining a force or distance advantage by modifying the ratio of lengths on either side of the pivot.
Example: Seesaw.