Levers work by having a effort that lifts a load, and a fulcrum balances the two.
A seesaw is an example of a lever. This is because it has a fulcrum in the middle of the bar. A class one lever always has a fulcrum that it not on either end of the bar. A force applied on one side of the lever is exerted across the fulcrum on the other side of the bar. The input force on one end of the lever is magnified by the difference in the length of the lever from the fulcrum to the input and the length from the fulcrum to the output of the force. This means that small forces in the input can be magnified if the input is far from the fulcrum while the output is close to the fulcrum.
A seesaw is an example of a lever. This is because it has a fulcrum in the middle of the bar. A class one lever always has a fulcrum that it not on either end of the bar. A force applied on one side of the lever is exerted across the fulcrum on the other side of the bar. The input force on one end of the lever is magnified by the difference in the length of the lever from the fulcrum to the input and the length from the fulcrum to the output of the force. This means that small forces in the input can be magnified if the input is far from the fulcrum while the output is close to the fulcrum.