Simple Machines: Wheel and Axle
Students will be able to explain how the wheel and axle work as a simple machine. Students will be able to identify objects which use the wheel and axle.
- Introduce the topic by telling your class that a simple machine is a device that can change the direction or strength of force. There are six simple machines that people can use to move objects.
- Activate students' prior knowledge with a question about items with wheels. For example, ask: What do a bicycle, skateboard, stroller, wheelchair, and car have in common?
- After the class points out that all of these machines have wheels, ask questions about how wheels work. For example: How do the wheels cause movement?
- Explain that wheels help things move by rolling.
Explicit Instruction/Teacher Modeling(15 minutes)
- Distribute small toy cars that have wheels joined by axles to groups of students. Kick-start a discussion with some questions about the toy car mechanics, such as: How do these toy cars move? How are the wheels on each side of the car joined to each other?
- Have a student volunteer point to the rod that holds the two wheels together. Explain that the bar that joins two wheels is called an axle.
- Tell students that they will be learning about wheels and axles.
- Hold up the doorknob, explaining that it is an everyday example of a wheel and axle.
- Challenge the students to help you identify the wheel and axle in the doorknob. Listen as different students call out their guesses.
- After some speculation, tell students that the knob that turns is the wheel. The inner rod that is attached to the knob is the axle.
- Demonstrate how the wheel and axle works by turning the knob (wheel). That turns the inner rod (axle) and moves the latch, to open the door.
Guided Practice/Interactive Modeling(15 minutes)
- To consolidate student thinking, set up activity stations with play dough and a rolling pin.
- Let students practice flattening the dough with the pin.
- Guide them to express these understandings: The rolling pin is a wheel and axle. When you push on the handles (the axle) the wheel turns and flattens out the dough.
- Challenge students to think of other common machines that have one wheel like the rolling pin. Great examples include a wheelbarrow, a top, and a playground merry-go-round.
Independent Working Time(15 minutes)
- Pass out a copy of the Wheel and Axle worksheet to each student to complete independently.
- Walk around the classroom to offer support to students who get stuck.
- Enrichment: Have students who need more of a challenge read a history of other simple machines, and fill out an accompanying word search.
- Support: Put students who need more support into pairs to complete the Wheel and Axle worksheet.
- Collect the worksheets that the students have filled out, and correct them using the Wheel and Axle answer sheet.
Review and Closing(5 minutes)
- In summary, remind students that the rolling pin is a wheel and axle. When you push on the handles (the axle) the wheel turns and flattens out the dough.
- Challenge students to think of other common machines that have one wheel like the rolling pin, such as a wheelbarrow, top, and merry-go-round.
- Remind your class that the wheel and axle is only one of six common simple machines that help things move. For homework or additional independent work, consider encouraging students to learn more about other kinds of simple machines.