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.