The load is the object you are trying to lift. It sits on the resistance arm of the lever. The effort is the force you use to push down on the lever to lift the load. It’s applied to the effort arm of the lever. The resistance arm and the effort arm are separated by the fulcrum, the point where the lever pivots.
Ruler (30 cm)
2 paper cups
A small rock or other weight
Handful of pennies
Label one cup “Load” and the other cup “Effort.” Use tape to attach the cups to opposite ends of the ruler.
Position the pencil underneath and perpendicular to the ruler, so the pencil crosses below the 5 cm line. It may be helpful to tape the pencil to the desk so it doesn’t roll around!
Place the rock in the “Load” cup. One by one, place pennies in the “Effort” cup until the load lifts into the air. Record the number of pennies it took using a table like the one below.
Position of Fulcrum
# of pennies
Repeat Steps 5 through 7 with the pencil placed at 15 cm and 25 cm.
Levers help us do work by multiplying the effort you use to move something. The closer the fulcrum is to the resistance force, the easier it is to lift the object. At the same time, the distance over which you must apply the effort increases. Levers do not increase the amount of work done; instead, they make work easier by distributing the effort over a longer distance.
© 2015 Museum of Science and Industry, Chicago – All rights reserved.
Visit the Museum of Science and Industry online! http://www.msichicago.org