SCIENCE CONCEPT: In a moving object there are dynamics that take place that were first described by a gentleman names Sir Isaac Newton. He stated them in Laws of Motion. In a portion of his First Law of Motion, Newton stated that an object at rest remains at rest and an object in motion remains in motion unless acted upon by an outside force. STUDENT OBJECTIVE: The student will explore this portion of Newton's Law using books and a chair or a cart on rollers. They will discover that an object in motion remain in motion unless acted upon by an outside force. OVERVIEW: In this activity, the student will discover how inertia works in relationship to objects. The student will stack books on the seat of a chair and push the chair forward and then stop the chair quickly. The chair will stop, but the books will continue to move forward through the air and then fall to the floor.

PREPARATION TIME: 10 minutes. LESSON TIME: 15 - 20 minutes. TEACHER PREP: Gather books and a cart with rollers if possible. If not use a regular chair.

WORDS TO KNOW:

push roll stop

continue motion inertia

TEACHER TEXT:

You and a frog have something in common. Both of you tend to keep moving once you both start moving. When you ride on a bus and the driver hits the brakes, the bus lurches to a stop. But you don't! You bump the seat ahead of you. You didn't stop moving when the bus did because of inertia. The bus brakes acted on the bus, but they didn't act on you. Inertia kept you moving until the seat in front of you applied a force and stopped you. A frog leaps and will soon land on the next lily pad. If there were no force of gravity pulling the frog down, the creature would shoot off in a straight path. That's what Sir Isaac Newton's First Law states: an object in motion will continue in motion in a straight line unless acted upon by an outside force. On earth, the force of gravity affects the path of the frog. So, instead of following a straight line, the frog curves back toward the ground, pulled by gravity. All objects have inertia. It's a physical property that keeps moving things moving or keeps motionless things still unless an outside force acts on them. Inertia kept you moving inside the bus until the force of the seat in front of you stopped you. A stationary object, such as a pebble resting on the ground, will continue to rest there motionless resting on the ground, will continue to rest there motionless unless an outside force, such as you shoe kicking it, moves it.

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