Energy systems


7. How to Build a Direct-drive or a Friction-drive Car


Each student writes an illustrated Instruction Manual, based on the steps they actually followed in making the direct-drive or friction drive car. The students give feedback to one another on their manuals, then revise the instruction manuals on the basis of the feedback.

Advance Preparation

  • Photocopy worksheets: “Instruction Manual for Making a Direct-Drive Car” and “Instruction Manual for Making a Direct-Drive Car”. Download below.
  • Photocopy form: “Student Feedback on another Student’s Manual”, Download below.


  • Direct-drive and friction-drive cars already made by students
  • Materials for making cars, for use as spare parts.
  • Worksheets for Instruction Manual for Making a Direct-Drive or Friction-Drive Car (see below).


  1. Class meeting:
    Students may already be familiar with How-to Books. An engineering term for a How-to Book is an Instruction Manual. Meet with students to discuss what an instruction manual is and how it can be used:
    Someone else might want to make what you made, and you might not be around to show them. Your Instruction Manual will tell them how to make one.
    You might want to make one yourself at a later date, but by then you might have forgotten how to do it. Your Instruction Manual will remind you about what to do.

  2. Writing instruction manuals:
    Each student writes his or her own Instruction Manual, using the Worksheets below.

  3. Testing instruction manuals:
    After students have finished writing, demonstrate how to test an Instruction Manual. Select an instruction that is vague, such as “Put the motor on the car” and deliberately misinterpret it; for example, by placing the motor so the shaft is pointing up. Ask students:
    What could happen if someone tries to follow an instruction that does not give enough information?
    Then ask students to exchange manuals in their groups, and and review them using the form “Student Feedback on another Student’s Manual.
    Revising instruction manuals. Ask students to revise their instruction manuals to provide all the information that is needed. This could be a homework assignment.


  • An instruction manual will tell someone else how to do what you did.
  • Writing and diagrams have to be clear and precise, or they will not be useful.
  • Writing and diagramming are design processes. You can analyze the weaknesses in your writing and diagrams, and redesign them to make them work better.
  • Word-wall: feedback.