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Grade: Middle
Subject: Science

#3937. Truth is stranger than FRICTION

Science, level: Middle
Posted Thu Mar 8 10:09:27 PST 2007 by Tim Mangiaracina (
MS88, Brooklyn, NY USA
Materials Required: 2 hot wheels cars, a smooth board covered in fabric, 3 textbooks
Activity Time: 1 45 minute period
Concepts Taught: experimenting on friction and how it works

Truth is Stranger than Friction
Motion, Forces and Energy
Mr. Mangiaracina

Objectives: 1. Friction is a force that opposes motion, or makes it difficult for an object to move across a surface.
2. The amount of friction depends on the surface type and the force pressing two surfaces together.
Materials: 2 toy cars cardboard towel or fabric textbooks
Tape yardstick
Procedure: Activity 1
1. Cover half the cardboard with the towel or fabric and tape it into place.
2. Write down observations about the 2 surfaces.
3. Using books, make a stack about 6 inches high and make a ramp with the cardboard.
4. Tape the board to the table so it doesn't slide.
5. Take the 2 cars and place them at the top of the ramp, use the yardstick to hold them
from rolling.
6. Make your hypothesis about the effect of the towel or fabric on the speed of the car
7. Raise the yardstick and observe how the car on the smooth side and the car on the
rough side moved. Did they move the same or differently? Write down in your
observation section of the organizer at least 2 sentences about what you saw.
Activity 2
1. Remove all from table except a large textbook.
2. Using only one pinky, push the text across the table.
3. Using the same pinky, push 2 textbooks across the table the same distance.
4. Write down any observations you might come up with from this activity, which was more difficult to push and why?

Conclusion Questions:

1. Explain how surface type influences the amount of friction there is.
2. What is the relationship between the size and weight of an object and the amount of friction that is present?
3. Analyze and explain how friction can be both a positive and a negative part of our everyday life. Use examples to support your statements.
4. Sports such as soccer involve running, stopping, jumping, and kicking. Explain how friction helps soccer players.
5. Describe a situation in which using wheels would reduce friction between a moving object and the surface it is traveling on.
6. Hypothesize how your life would be if there were no friction. Which actions would be more difficult? Which would be easier?

If you are Creating a Lab Report, it needs to be written in pencil on loose leaf or typed on computer, if not use Loose leaf to write your hypothesis' and Observations and write your questions with answers.