Standard 3, Objective 1

Utah Core, 3rd Grade Science

Standard 3, Objective 1 

Demonstrate how forces cause changes in speed or direction of objects.

1. Show that objects at rest will not move unless a force is applied to them. 
2. Compare the forces of pushing and pulling. 
3. Investigate how forces applied through simple machines affect the direction and/or amount of resulting force. 

Activity:

Use two broomsticks and a rope to create a simple pulley. Demonstrate how the force applied through this simple machine is much stronger than the force we can apply without it. One student pulling on the rope will be stronger than two students trying to hold the broomsticks apart. See the following document for directions:

http://www.msichicago.org/fileadmin/Education/learninglabs/lab_downloads/Pulley.pdf

Activity:

After discussing the demonstration and the effect of a simple machine, have students write a short description about what happened with the demonstration. Ask them to explain what made the difference so that one child was stronger than two!

Essential Questions:

1. What is another way you could use a pulley to do work?

2. Is there any other kind of simple machine that could help pull the broomsticks together?