1. Preparation materials: (Two cans need to be prepared by parents themselves! ) polished rod, perforated wood square, small motor, battery box, 5th battery, clip, plastic gasket, pulley, rubber band, double-sided tape, wire binding, 502 glue, white latex, perforated log piece.

2. Remove the middle part of the two cans with pliers.

3. Make a small hole in the bottom center of the two cans with an awl.

4. Prepare double-sided adhesive tape on four logs.

5. Stick two logs in the center of the top of the two cans with double-sided tape.

6. Stick the remaining two logs in the center of the bottom of the two cans with double-sided tape.

7. Pass two polished rods through the log holes on the two jars respectively.

8. Gaskets are fixed at both ends of the two polished rods respectively.

9. Put two rubber bands on one of the jars (one rubber band is reserved for use).

10. Install two long wooden squares with holes and fix them with gaskets at both ends.

1 1. Use 502 glue to stick the long wooden square without holes on two long wooden squares with holes (pay attention to adjusting the distance).

12. Put the pulley on the central shaft of the small motor.

13. Fix the small motor at one end of the crossbar with a tie.

14. Put one end of the rubber band on the can edge and the other end on the pulley.