# AGRIC6: Simple Mechanics

### Vocabulary

axle: the bar or rod on which or with which a wheel or wheels turn

inclined plane: a flat surface that is higher on one end; a simple machine used to move objects to a lower or higher place

lever: a device which pivots on a fixed point called a fulcrum

machine: a device used to help make work easier

pulley: a wheel over which a rope or chain passes; used to lift or move things

screw: theoretically a rolled up inclined plane; a simple machine used to hold objects together or lower and raise things

wedge: a triangle-shaped object with one pointed end and one thicker end; a simple machine used for raising, holding, or splitting objects

wheel: a disk or circular object arranged to revolve on or along with an axle that passes through its center

### Background Agricultural Connections

This lesson is part of a series called Simple and Complex Machines Used in Agriculture. These lessons introduce students to the simple and complex machines used in their daily lives and in food and fiber production. Through a variety of hands-on activities, students create models of the six types of simple machines and discover the concepts of force and friction. The essential role of complex machines in people’s daily lives and in agriculture is interwoven through a number of class and homework activities that incorporate cooperative learning, writing, mathematics, art, and drama. Together these activities are designed to stimulate creative thinking and motivate learning. Other related lessons include:

Activity 1: Six Simple Machines

1. Lever Activity:
1. Cut out the lever pattern.
2. Fold and tape the base (fulcrum).
3. Set a small paper clip on one end of the lever and push the other end down. It should lift the paper clip up.
• There are three classes of levers. The model is a first class lever.
• Examples of levers include: see-saws and car jacks (first class), wheelbarrows and nutcrackers (second class), and shovels and brooms (third class).
• A lever has three parts—effort, fulcrum, and load or resistance. The fulcrum is the point on which the lever pivots. This allows the weight to be moved a short distance with a concentrated amount of force (effort).
2. Inclined Plane Activity
1. Cut out the inclined plane patterns found in the attached Simple Machine Templates file. Fold and tape as shown.
2. Set the inclined plane on the table with one long side down.
3. Roll a pencil up and down the incline.
• Examples of inclined planes include boat ramps, stairs, wheelchair ramps, truck loading ramps, driveways, and grain elevators.
• An inclined plane makes it easier to move an object to a higher or lower place.
3. Wedge Activity
1. Cut out two wedge patterns found in the attached Simple Machine Templates file.
2. Fold and tape them together.
• Examples of wedges include axes, wedges, nails, ice picks, knives, plows, discs, and treads on tires.
• A wedge is a triangle-shaped object with one pointed end and one thicker end. A wedge makes work easier for people by raising, holding, or splitting objects.
4. Screw Activity
1. Cut out the triangle found in the attached Simple Machine Templates file.
2. Using the arrows as a guide, roll the paper around a pencil and then tape in place.
• Examples of screws include bolts, wood screws, jar lids, augers, and drill bits.
• A screw is an inclined plane rolled up. A screw is a simple machine used to hold objects together or lower and raise things.
5. Wheel and Axle Activity
1. Cut out the two circle patterns found in the attached Simple Machine Templates file and punch or poke a hole in the center of each circle. The hole should be slightly smaller than the diameter of the straw.
2. Insert the straw through both holes.
3. Roll the wheel and axle across the desk. The circles are the wheels and the straw is the axle. If appropriate, have the students tape the wheels to the axle.
• Examples of wheels and axles include tires, doorknobs, the crank shafts on bicycles, steering wheels, gears, and egg beaters.
• A wheel and axle reduces the amount of friction an object creates during its motion. A wheel revolves on or along with an axle that passes through its center.
6. Pulley Activity
1. Cut a 1′ (30.48 cm) piece of string, and thread it through the middle of a round wooden tinker toy, drapery pulley, thread spool, or bobbin.
2. Tape the two ends of the string on the edge of the desk so that the “pulley” hangs freely off the edge of the desk.
3. Thread the 2′ (60.96 cm) piece of string around the top of the pulley so that it fits into the groove. Have students attach their pencils or other objects to one end of the string and provide time for students to experience how a pulley works.
• Items that contain pulleys include drape draws, elevators, flagpoles, sails on windsurfers and sailboats, scaffolding for window washers, engine hoists, and cranes.
• Pulleys make work easier by changing the direction of the force applied. With a pulley, when one pulls down, the object goes up.

Activity 2: Simple Machines—Can You Match Them?

1. After discussing the directions on the activity sheet, have each student complete the activity, Simple Machines—Can You Match Them?
2. Direct a classroom discussion to assess the results of the students’ work.

Activity 3: Machines Helping the Rancher

1. After discussing the directions, have each student complete the activity, Machines Helping the Rancher.
2. Direct a classroom discussion to assess the results of their work.

Activity 4: Keeping It Simple

1. Distribute and explain the homework assignment, Keeping It Simple to your students. Have the students complete the assignment at home.
2. After collecting the homework, discuss which kinds of machines seemed to be the most common around the house.

Conclusion:

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