GRADE: Third

CONTENT STANDARD: Physical Science

CONTENT TOPIC: Simple Machines/Technology

CONCEPT: Machines use energy to make work easier.

CONTENT OBJECTIVE: 3A4.00 To understand force and how it can be applied

INSTRUCTIONAL OBJECTIVES: The learner will:

4.01 define force and identify the cause of movement as pushing or pulling.
4.02 relate the types of force used in operating the six simple machines.
4.03 identify which object requires the most force to move.

I. Define force
II. Relate the types of force when using the six simple machines
III. Discuss which object uses the most force

TN COMPONENT OF SCIENCE: Process Of Science

TN GOAL:

To enable students to demonstrate the process of science by posing questions and investigating phenomena through language, methods and instruments of science

1.1 OBSERVING - The senses are used to develop an awareness of an event or object and the properties thereof.

1.1a Observing is a process used to develop an awareness of the surrounding environment.

BENCHMARK: Awareness of our surroundings is a result of individual observations and prior knowledge.

TIME REQUIRED:

Three lessons, 30 minutes each

Simple machines, objects in classroom, cardboard, paper clips, tape, rubber bands, large rope

Today, class, we are going to define force; identify the cause of movement, as pushing or pulling; relate the types of force used in operating the six simple machines; and identify which object requires the most force to move.

Force is anything that causes an object to move or accelerate. An object's motion changes more if you apply a stronger force. We can relate the types of force used in operating the six simple machines. A lever is a long, rigid bar with a support. (Ask children if they can name an example of a lever crowbar, seesaw.) A lever can help you move objects by multiplying the force you exert.

Another simple machine that can be thought of as a special lever is a wheel and axle. A wheel and axle works together. If you push on the wheel, the axle also turns. If you rotate the axle, the wheel turns also. An example of a wheel and axle is a screwdriver.

A pulley consists of a grooved wheel over which a rope passes. Some pulleys may change the direction of force. An example of this is the pulley on a flagpole that raises and lowers the flag.

An inclined plane is a flat surface with one end higher than the other. You exert less force on a long slope than on a short one. An example of this is that it is easier for a dock worker to slide a heavy box up a plank onto a dock than to lift the box and put it on the dock.

A wedge is an inclined plane with either one or two sloping slides. A knife is a wedge with two sloping slides. Each sloping slide would be thought of as an inclined plane.

A screw is a spiral inclined plane. The screw works by increasing and transferring the force that is exerted on it. When you turn a screw, the direction of the force changes.

When using any of these simple machines, the types of force will vary. Objects with a large mass require more energy to move than objects with a small mass.

1. Have students manipulate simple machines to determine if a push or pull is necessary to operate the machines.

2. Playground equipment may be used as examples of machines.

3. Have the students identify objects in the room that require the most force to be moved. Rank these objects.

4. Have the students construct a force-o-meter with cardboard, paper clips, tape, and rubber band. Lift objects with the force-o-meter. Force is related to the amount the rubber band stretches.)

Each student divides a sheet of paper into three columns. Label them "Push," "Pull," and "Lift." Ask the students to name objects that do these things, and tell in which column each object should be listed.

Students tour a factory to see "work." Students should evaluate the type of work a machine does ( a fork lift, lifts etc.) Make a point to ask the Safety Supervisor to clarify the company's safety policy and incentives (see next lesson concerning safety rules).

This is the time this file has been accessed since 05/18/97.

The University of Tennessee at Martin is not responsible for the information or views expressed here.

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