Do this as a home lab activity have parents sign it.

    Items used: Toy Car
                        Stack of coins
                        Writing utensil
                        Masking tape

    Procedure: Follow steps in the book on p. 44M.

    Assignment: See page 44M

Assign Reading

    Go over "Guide for Reading" and "Reading Strategies" p. 44 m

Objectives: The student will be able to…

• Explain how balanced and unbalanced forces relate to motion
• State Newton's first law of motion

1. Place a book on the table for each group have them take turns finding ways to move it using a different method each time.
2. Have them list methods and write whether they are using a push or a pull.
3. Discuss their brainstorming lists.

• "What does it always take to move an object?" a push or a pull, so all motion needs some type of push or pull.
• What about a ball rolling down a hill or an apple falling from a tree?
• The moon moving through space, Earth orbiting the sun? All motion needs a push or a pull and these are the types of questions that Newton asked when discovering the laws of motion.

• Have students read pp. 44-46.
• What causes objects like an arrow, soccer ball or long jumper to move?' Push or pull
• What causes them to stop? Push or pull
• What if you want to change direction? Push or pull
• A push or pull on an object is called a force.
• If an object is moved by a push or pull we say there is a force working on it.
• Like velocity and acceleration, forces are described by how strong they are and by the direction they are moving in. We show these forces with vector arrows.

• Because forces are in vectors they can add together if they all push the same direction.
• EX:

1. Try to lift your chair with one finger.
2. Now you and your partner try to lift your chair with one finger.
3. Now you and a third person try to lift a chair,
4. now a fourth person.

• Does the chair get easier to lift each time?. That is because the force from each of you is added together.

1. Draw the force diagram on the board.

• When forces are added in opposite directions they also add together
• The direction of movement is always in the direction of the overall force.
• EX: Arm Wrestling both people exert a force but the one with the greatest force wins. The force he may win by may be very little and it may be very difficult if they are almost equal. If one is much stronger then he has more than enough force and wins easily
• We show the forces applied with vector arrows. And the resulting force with a net arrow. Each is usually a different color and size with size based on the largest force.
• Anytime you have a net force you have unbalanced forces. Unbalanced forces result in a change in motion.

• Forces exerted on an object do not always change the motion.
• EX: Your chair on the floor is a force, but neither are moving
• EX: To arm wrestlers of equal strength, neither one moves
• EX: Two people on a teeter totter with their feet off the ground
• When forces are exerted but no change in motion occurs you have balanced forces.

Newton’s First Law of Motion p. 48 Book M

    DEMO: Have students push their book a short distance on their desk.

    How do you keep it moving at a constant speed? Push it with a constant force

    How do you get it to stop? Stop applying the force

Aristotle: 2000 years ago Was a Greek philosopher, similar to a scientist who tried to determine how the world worked. One of the things he discussed was how things move. He came up with three statements that discuss motion.

1. To set an object in motion a force is needed.
2. To keep an object moving at constant speed a constant force needs to be applied.
3. If the force is removed the object will stop.

Galileo Galilei: Early 1600’s was an Italian astronomer who would later become more famous for his work on the planets.

He had a problem with the idea that a force is needed to keep objects moving. He saw how the planets moved no push or pull was needed to keep them moving.

1. Force is needed to start an object moving.
2. No force is needed to keep it moving.
3. Forces are needed to change direction (orbit) or stop motion.
4. At moving, or at rest, all objects resist motion this resistance to motion is called Inertia.

1. Force is needed to start motion
2. It continues on its own without outside forces.
3. Another force is needed to stop or change direction.

Sir Isaac Newton late 1600's

• Newton's First Law of Motion: Newton looked at Galileo's ideas on inertia and tried to apply it to the Universe instead of just to objects on the Earth like the Greeks did.

• Newton’s First Law of Motion States that an object at rest will remain at rest. And an object that is moving at constant speed will continue moving at constant speed unless acted on by an unbalanced force. This is also called Newton’s Law of Inertia.

1. EX: Jumping in an airplane going 330 mph
2. EX: Jumping in an airplane and a wind gust slows the plane
3. EX: Jumping in an airplane on the outside.
4. EX: Crash test dummies in Fig. 4 and your discover activity

DEMO: Baseball and rubber baseball. Bounce baseball then switch it and throw the rubber baseball. They know the inertia is different.

Mass:one physics definition of mass is any object with inertia. This is especially hard to determine with very small pieces of matter like parts of atoms, are they energy or are they matter?

A cup card and water, DEMO, also coins on your elbow, table cloth and set table.

Go over activity in the book p. 25M

Skill Lab p. 26M and 27M:

Handout and do with golf balls and rulers or meter sticks.