Inclined Plane

INTRODUCTION

Inclined planes are useful in many ways, more than are usually noticed. Inclined planes, like all simple machines, make work easier. The goal of this experiment is to demonstrate how an inclined plane lowers the amount of force needed to raise objects.

MATERIALS

• 3 boards (12, 24, and 36 inches long)
• Pile of books or support for the boards
• 200 gram weight
• Spring scale or clamp pulley
• Paper or plastic cup
• Gram weights

WHAT TO DO

1. First use the spring scale to measure the force needed to lift the weight straight up from the tabletop to the top of the books or support.
2. Form an inclined plane between the tabletop and top of the pile of books. Slide the weight up the inclined plane from the tabletop to the top of the pile of books. Measure the force needed to move the weight using the spring scale or by adding the gram weights to the cup, which is connected to the weighted string that is threaded through the pulley.
3. Measure the force necessary to move the weight using all three boards.

QUESTION

1. Which board required the least applied force to move the weight to the top of the pile of books? Why?

EXTENSION

1. You are an engineer for the space station; make a drawing that illustrates the use of inclined planes on the space station.
2. Make a list of inclined planes in your house.

SUMMARY

Inclined planes trade distance for applied force. Examples of other inclined planes-stairs, wheelchair ramps, roads that wind up mountains, and screws (a screw is an inclined plane wrapped around a shaft).

SOURCE

"Machines." Janice Van Cleave, John Wiley, and Sons, New York. ISBN:0-471-57108-3.
"Bathtubs, Slides and Roller Coaster Rails: Simple Machines That Are Really Inclined Planes." Christopher Lampton, Millbrook Press, 1991. ISBN: 1-878841-23-8.

Grade Level: Appropriate for grades K through 5.

© S. Olesik, WOW Project, Ohio State University, 2001.