Lesson Six

Inclined Plane

                Work  smarter, not harder

Objectives:Students will be able to:
   Define inclined plane.
   Describe the uses of the inclined plane.

Time and Materials:
   30-60 minutes
   3  thick books, 1 smaller book, 1 board approximately 8"x 48", spring scale, approximately 24" of  string.

   Review what a simple machine is.(Something that helps people do work)  Does a simple machine have a motor?  Where does it get its power?
   Has anyone ever ridden up a driveway on a bicycle rather than go over the curb?  Why?  A driveway is a kind of ramp.  What other ramps do you know?  Ramps are a type of simple machine called an inclined plane.
   An inclined plane is usually a flat surface on a slant.  It helps us do work more easily because it moves the load gradually.  We are going to do an experiment today to see how the inclined plane helps people do work.

   1.  Tie the string around one of the large books and attach the spring scale.  What does the spring scale do?(measures the force used to move a load)  Have a student lift the book using the spring scale and record the amount of force needed on the chalkboard.
   2.  Now we'll use the inclined plane to move the same load.  Set the end of the board on the books to create a ramp and have a student pull the book attached to the spring scale up the inclined plane.  Will this take more or less force than lifting the book?  Record the force used on the chalkboard.  If we increase the angle of the inclined plane will it be harder or easier to raise the load?  It is easier to move a load up a gradual incline than a shorter, steeper inclined plane.
Allow the students time to record their observations and conclusions using the steps of the scientific method found in their Science Journal.

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