Inspired by the Cycle for Science activity:

“Cycle for Science DIY” allows for educators and/or students to modify the activity in the following ways:

-Developing a physical model of a trek bike.

-Transferring model to a 3D CAD design.

-3D printing the CAD Design.

Materials needed per unit trek bike:


  1. Make the back wheel section:
  1. If your straw has a small section on one side of the bendy part, cut the small section off.
  2. Cut about 4 inches off of the skewer (including the pointy part) and insert the skewer into the straw.
  3. Drill holes into the middle of the wheels (if not there already) big enough to fit snuggly into the skewer. Place wheels on the two ends of the skewer.
  1. Glue one end of the popsicle stick on the middle of the back section.

(See pictures for steps 3 – 7)

  1. Undo both of your paper clips.
  2. Glue one end of one of the paper clips on the back of the solar panel and the other end on the middle of the popsicle stick. This mechanism will allow you to tilt the solar panel to the direction of the sun or artificial light source.
  3. Attach the little gear wheel to the shaft of the motor.
  4. Modify and maneuver the second paper clip so that one end is going around the popsicle stick to secure it and the other end (on top of the popsicle stick) is in a tilted position.
  5. Hot glue the motor to the tilted part. The tilt will ensure that only the tip of the wheel on the motor is touching the ground. The small area covered by the tip of the wheel reduces the force required for the motor to get the wheel moving.
  6. Connect the wires coming from your solar panel unto the motor.
  7. If not enough sunlight, use a powerful halogen lamp to get your trek bike going.


  1. 3D-printable file can be found at:
  1. You still need to work with the paper clips to make the tilted motor setup and the modifiable tilt solar panel.
  1. Want to try 3D Drawing on your own!?
  1. Why don’t you try to draw your own physical model into TinkerCAD?
  2. Go to YouTube Autodek Tinkercad channel for tutorial videos. Here is a good introductory one to begin with:


Prior to the building of the trek bike:

  1. Introduce: the car as an example of prototyping
  2. Solar panels + demonstration of how it works
  3. Quick intro to drawing a circuit
  4. Present materials
  5. 10 minute draw time
  1. How does it move / what forces are acting on it
  2. Does the angle of the solar panel matter?
  1. How could you change it?
  1. How are the wheels attached? How do you make sure they still spin?
  1. 15 minute tinker time