Students explore simple and complex machines and discover how they are used in agriculture. Grades K-2

agriculture: the science or practice of farming, including cultivation of the soil for the growing of crops and the rearing of animals to provide food, wool, and other products

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

complex machine: two or more simple machines working together

force : a push or a pull on an object

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

Simple and complex machines are used in our daily lives and in agriculture. Machines are devices that help make work easier. A simple machine is a device that changes the magnitude or direction of a force—a lift, a push, a pull, or anything that makes an object move or remain still. A complex machine consists of two or more simple machines working together. Most machines consist of multiple elements that work together in a complex way. But no matter how complex they are, machines are made up of one or more simple machines. There are six types of simple machines—wedge, inclined plane, screw, lever, wheel and axle, and pulley.

Wedge: A wedge is a triangle-shaped object with one pointed end and one thicker end. It is used for raising, holding, or splitting objects. A wedge makes it easier to split things apart. When the wedge is pushed down, the object it is pushed into splits apart. For example, after a farmer harvests apples and sells them, the apples are often peeled, cored, and sliced to be used into pies. The knife, apple peeler, and cutter used to prepare the apples are wedges.

Inclined Plane: An inclined plane is a flat surface that is higher on one end. It is used to move objects to a lower or higher place. It is much easier to move a heavy weight up or down if an inclined plane is used. A ramp (a type of inclined plane) is very useful when a cattle rancher loads cattle onto trucks to move them from one pasture to another.

Screw: A screw is a rolled up inclined plane. It is used to hold objects together or lower and raise things. In an agricultural machine called a combine, an auger—or moving screw—pushes grain into a container.

Lever: A lever is a device which pivots on a fixed point called a fulcrum. A lever makes it easier to move heavy things. Levers concentrate a force around a pivot point. A cattle rancher needs to use fences around the pasture. The heavy gates open and close easier because they have hinges that are levers. The gate fasteners are often levers too.

Wheel and Axle: A wheel is a disk or circular object arranged to revolve on or along with an axle that passes through its center. An axle is the bar on which or with which a wheel or wheels turn. Wheels allow things to roll instead of slide when a force is applied. Wheels help move objects.

Pulley: A pulley is a wheel over which a rope or chain passes. It is used to life or move things. Pulleys make lifting easier for people by changing the direction of a pull. There are many different kinds of pulleys that lift and move heavy loads. A pulley can be used to place hay in a barn.

1. Read Hey, Hey, Hay! by Christy Mihaly aloud to the class. As you read, ask the students to raise their hands when they see a tool or machine being used to do work on the farm. Stop each time hands are raised and write the name of the tool on the board. (pitchfork, tractor, mower, tedder, hay rake, baler, grapple)
2. Clarify for the students that a machine is a piece of equipment that helps make work easier. Most of the machines on our list are complex machines. They are made up of two or more simple machines working together. 
3. Explain to the students that they will be exploring the six different types of simple machines and discover different ways machines can be used to make the process of growing and producing our food and fiber easier.

Activity 1: Simple Machines Exploration

1. Prior to this activity, place the station materials and instructions in six locations around the room.
2. Divide the class into six groups. Explain to the groups that they will be rotating through six discovery stations.
3. Have the groups rotate from station to station every 10 minutes, completing each activity. Give the groups a 5-minute and 1-minute warning before time is up. Variations: Do each station as a whole class activity. Assign older students from another class or parent helpers to lead each station. 
4. When the rotations are complete, lead a class discussion about each simple machine:
   • Wedge:
     • Ask the students, "What was the wedge in this activity?" (the knife or apple cutter)
     • Ask, "What did the wedge do?" (The wedge cut the apple apart.)
     • Ask, "What wedges did you use in your mouth?" (Teeth)
     • Explain that tractor tire treads are wedges. Ask, "Why are there treads on tires?" (Tractor tire treads dig into the ground for traction.)
     • Ask, "What are some examples of wedges?" (jack hammer, knife, chisel, hatchet, ax, plow, nail, fork, pizza cutter, tire tread, hoe)
     • Read the section about wedges in Simple Machines by David Adler.
   • Inclined Plane:
     • When did the rubber band stretch less—using or not using the inclined plane? (The rubber band stretched less when using the inclined plane.)
     • Farmers use ramps to load and unload animals from trucks. When does an inclined plane come in handy for you?
     • Ask, "What are some examples of inclined planes?" (ramp, stairs, slide, loading ramp, conveyor belt system, escalator, wheelchair ramp, grain elevator, skateboard ramp)
     • Read the section about inclined planes in Simple Machines by David Adler.
   • Screw:
     • Ask the students to describe what they did to put the screw through the pieces of wood.
     • Ask, "Did the screw go away from you or towards you?" (The screw went away from me.)
     • Explain that screws can be used to hold objects together, like in the activity, but can also be used to lower or raise things, like a grain auger. Show how a grain auger works by viewing minutes 7:55-8:32 of the Everything About Grain Bins video.
     • Ask, "What are some examples of screws?" (propeller, meat grinder, pencil sharpener, windmill, grain auger, wood screw, jar lid, bolt, hose nozzle)
     • Read the section about screws in Simple Machines by David Adler.
   • Lever:
     • Ask the students to describe how it felt to pick the books straight up with their hands.
     • Ask, "Was it easier or harder to lift the books using a lever? Why?" (Easier, because the lever allows you to use less force.)
     • A shovel lifting soil out of the ground is an example of a lever and a wedge. How can a shovel make the job of lifting soil out of the ground easier? (A shovel helps you to move more soil using less force.)
     • Ask, "What are some examples of levers?" (wheelbarrow, crowbar, oar, nutcracker, scissors, pliers, see-saw, salad tongs, hoe, rake, broom, shovel, tweezers, hammer, tin snips)
     • Read the section about levers in Simple Machines by David Adler.
   • Wheel and Axle:
     • Ask, "What happened to the rubber band when you pulled the books without using the wheels?" (The rubber band stretched far.)
     • Ask, "What happened to the rubber band when you pulled the books with the wheels?" (The rubber band did not stretch as far.)
     • Ask, "Did it take more or less force to pull the books when they were on wheels? Why?" (It took less force because there was less friction.)
     • Ask, "What are some ways farmers use wheels and axles to make work easier on the farm?" (farm vehicle wheels, wagon wheels, cart wheels, wheel line irrigation, etc.)
     • Ask, "What are some examples of wheels and axles?" (bicycle wheels, skate wheels, potter's wheel, spinning wheels, Ferris wheels, egg beater, wheelbarrow, windmill, vehicle tires, door knob, wagon wheels, steering wheels, gears)
     • Read the section about wheels and axles in Simple Machines by David Adler.
   • Pulley: 
     • Ask, "Was it easier to lift the books with your hand or the pulley?" (the pulley)
     • Explain to the students that farms long ago used simple pulley systems to place hay in a barn. Ask, "What are some examples of pulleys?" (elevator pulleys, crane, flag pole pulleys, engine hoist)
     • Read the section about pulleys in Simple Machines by David Adler.

Activity 2: Machines on the Farm

1. Reorganize the students into six groups. Provide each group with one of the three Farm Pictures so that each picture is given to two groups. Each group should also be given a piece of poster paper and markers.
2. Explain to the groups that each picture contains a scenario on the farm where a simple or complex machine can be used to complete a task. Remind the students that a complex machine is made up of two or more simple machines working together. 
3. Have the students work in groups to determine what kind of simple or complex machine will help perform the work. Ask the students to draw a large picture of their solution on the poster paper and label the simple machines.
4. Allow time for each group to share their solutions with the class.
5. After the groups have presented their ideas, share with the class the ways in which the tasks are often performed on farms. Compare how the group ideas were similar or different.
   • Moving the baby calf: Placing the calf in a wheelbarrow uses a wheel and axle and a lever to lift the weight of the calf and move it to the new location.
   • Transporting grain to the silo: Grain is often moved from place to place with an auger. An auger is a rotating screw located inside a tube. As the screw rotates, the grain is moved up the tube and into the silo.
   • Transporting hay bales: Most large hay bales are lifted using a loader. Loaders use a lever to lift the bale. The bales are then loaded onto a trailer which uses wheels and axles.

After conducting these activities, review and summarize the following key points:

• There are many simple tools and complex machines used in agriculture.
• Tools and machines make the process of growing and producing our food and fiber easier and more efficient.
• Farmers and ranchers can produce more food with less effort with the use of machines and tools.

• Big Book of Big Tractors
• Big Tractor
• Hey, Hey, Hay!
• Machines on the Farm
• Simple Machines: Wheels, Levers, and Pulleys
• Tractor Timeline- A History of Tractors
• Trax the Tractor and His Farming Friends
• Up Close Experience: Combines