Introducing Force and Work

Objectives:

• Students will define force as a push or a pull.
• Students will identify when they have used force in their lives.
• Students will learn a new definition for work. Work is a push or pull on an object causing movement.

Materials:

• Chairs and other moveable objects

Procedures:

1. Ask children to move something surrounding them, their chair, pencil, book, paper, desk, etc.
2. Ask what caused the objects to move. (push or a pull)
3. Tell the children they used a "force" to move the objects. Write force on the board.
4. Ask the children other ways to move objects. (Use their legs, use their bodies, use other objects, etc.) When have they used force in their lives?
5. Lift a book. Ask if this is a pushing or pulling force. (Pulling it up into the air.)
6. Ask the children what "work" is. Children may talk about their parent's going to work, a job. Explain there is another definition for work, a scientific definition. Work is using a force, push or pull, to move an object a certain distance. The actual definition of work is Work=Force x Distance. Write this on the board.
7. Have a student push against the wall as hard as they can. Have another drop a piece of paper on the ground. Ask the class who is doing more work. The children may answer the one pushing the wall.
8. Explain to the children that the wall pusher is doing no work at all. Ask the children if they know why by looking at the definition of work. The wall pusher has force but no distance. The wall is not moving anywhere. The paper dropper has both the force of pushing the paper to the ground, and the paper is moving a distance.
9. Give the children examples of work and non-work. Have them call out whether it is work or non-work. Ask a child why he/she answered the way she did.

Evaluation:

1. Were children able to identify what they use to move objects?
2. Were children able to give examples of times when they have used force?
3. Were children able to accurately distinguish between work and non-work activities?

Reteaching:

• Give numerous examples of work and non-work. Show why there is a force or no force. Show whether there is movement or no movement.

Challenges:

• Have children show examples of work or non-work. Have classmates call out whether work is being done.