# Force, Friction and Washington

### Summary

Students will learn about the intuitive meanings of Newton's first and third Laws of Motion through coin related science experiments.

• Quarter

• Generic

• Science

### Class Time

Sessions: One
Session Length: 90 minutes
Total Length: 46-90 minutes

• Whole group
• Small groups

• Force
• Friction

### Preparations

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1. Discuss with students how people try to find answers to their questions. We are constantly trying to understand our world and asking questions like Why do the sun and moon move through the sky, why does it get dark, and why do things fall to the ground. Isaac Newton, who was born in 1642, guessed that there must be some basic laws that governed or controlled these and other motions. He was right, and he discovered those laws that are today known as Newton's three laws of motion.
2. Write on the board Newton’s First and Third Laws of Motion:

Law 1: Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.

Law 3: For every action there is an equal and opposite reaction.

3. Explain to the students that they will be working in groups of 2 or 3 to explore these ideas. Each group will have 2 quarters, graph paper, a tape measure and something to write with. They will need a flat surface to work on.
4. Have the students conduct the following experiments and record their observations.
• Slide a quarter across a smooth surface (slate) and then across a rough surface (carpet). Try to use the same force for each surface. Write down your observations.
• Place one quarter about 12 inches from another quarter on a smooth surface. Hit one quarter so that it slides and hits the other quarter. (It works well to flick with your finger and thumb.) It may take a few tries to hit it, using different forces. Record your observations.
5. Have the students come back together and discuss their findings.
6. Introduce the concept of Friction (the force that resists relative motion between two bodies in contact).
7. Talk about how the experiments illustrate Newton’s laws.

### Enrichments/Extensions

Have students hit the quarter at different angles. (With some practice, they can see how forces are vectors and different striking angles produce different results, but still equal and opposite reactions.)

Use the students' observations recorded during the experiments to ascertain whether they have met the lesson objectives.

### Games

This lesson plan is not associated with any Common Core Standards.

Discipline: Science
Domain: 5-8 Content Standards
Cluster: Physical Science
Standards:

• Properties and changes of properties in matter
• Motions and forces
• Transfer of energy

Discipline: Science
Domain: 5-8 Content Standards
Cluster: Science as Inquiry