Students investigate six kinds of simple machines—inclined plane, pulley, screw, wedge, lever, and wheel and axle, and determine that simple machines can be combined to form complex machines. Grades 3-5

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

complex machine: two or more simple machines working together

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: an apparatus using or applying mechanical power and having several parts, each with a definite function and together performing a particular task; 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

simple machine: a device that changes the magnitude or direction of a force

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

1. Print one copy of the attached file, Simple Machine Pictures. Place the pictures of the six simple machines on the board in front of the class. Explain that each picture represents a simple machine.
2. Draw on the prior knowledge of your students by asking them if they can name any of the machines.
3. Place the word strips with the names of the machines where the students can see them. Help the students match the word strip with the correct machine. Inform your students that they will be learning how these simple machines work and how they make hard jobs on the farm easier.

Activity 1: Six Simple Machines

Discuss with the students that each team will do the following for each simple machine:

• Make a model of it.
• As it is built, discuss geometric terms such as faces, vertices, planes, etc.
• Write the name of the simple machine on the model.
• Explain how it makes work easier for people.
• Create a list of examples of the simple machine.

1. Lever Activity:
   1. Cut out the lever pattern from the Simple Machine Templates.
   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 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 Simple Machine Templates.
   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 Simple Machine Templates.
   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 Simple Machine Templates 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:

Variations

• Bring in a large variety of simple machines. Divide the class into two teams in front of a starting line, giving each team an equal number of machines. Set up large name cards for each kind of simple machine at a finish line. Have students carry their machines to the finish line and place them in front of the correct name card. The team that completes its work the fastest is the winner. Call this game the Machine Relay.
• Gather small machines such as an eggbeater, spatula, wooden spoon, rolling pin, paintbrush, screwdriver, hammer, toy tractor, key, and tweezer. Place each machine in a brown paper bag. Have a student reach in, feel the machine, and answer a variety of questions pertinent to the machine. As the student answers the questions, have the rest of the class try to identify the machine. Possible descriptive questions are listed below:
  • Is it hard or soft?
  • Is it rough or smooth?
  • Is it large or small?
  • What do you think it is made of?
  • Who might use it and for what reason?

After conducting these activities review and summarize the following key concepts:

• Tools and machines make work on a farm (or other location) easier.
• There are 6 simple machines- levers, wedges, screws, wheels and axels, pulleys and inclined planes.
• When multiple simple machines are combined, they form a complex machine.

This lesson was funded in 1996 by the California Beef Council and the California Farm Bureau Federation. To meet the needs of California educators, Simple and Complex Machines Used in Agriculture was revised to support the Curriculum Content Standards for California Public Schools and updated to include recent agricultural innovations. Funding from the Wells Fargo Foundation made this revision possible.

Illustrators: Karin Bakotich, Pat Houk, Sherri Hughes, Regina Johnson
Layout and Design: Nina Danner

• Hey, Hey, Hay!
• Machines on the Farm
• Modern Marvels: World's Largest Combine
• Simple Machines: Wheels, Levers, and Pulleys
• Tractor Timeline- A History of Tractors
• Up Close Experience: Combines