Overview

In this lesson students create MechAnimations that they can take home. These are based on their pegboard mechanisms and the stories they want to illustrate.. They are introduced to buckling, then they explore the resistance of cardstock and cardboard to buckling forces. They learn ways to transfer a mechanism from pegboard to cardboard and cardstock. They apply this information in the MechAnimations they design.

Materials

• Students' pegboard mechanisms on which they will base their MechAnimations.
• Cardstock: 100 sheets and 200 strips (1” x 11”)
• Corrugated cardboard:  50 sheets (8 ½ x 11") and 200 strips (1 x 11")
• Paper fasteners – 2 boxes of 100 each
• Markers & craft materials for decorating MechAnimations
• Science notebooks

Procedure

1.      Whole-class meeting: buckling. Demonstrate buckling using a pegboard strip and a cardstock strip. (See a video on buckling)

2.      Force and buckling exploration.  Distribute a cardboard strip and a cardstock strip to each student.  Students investigate the force needed to push an output link of their own mechanisms at different distances from the fixed pivot. They push with their fingers, cardboard strips and cardstock strips.  Here are suggestions for the exploration and a video.

3.      Whole-class meeting: force, distance and materials.   Introduce the concept of force: the amount of push or pull used to make something move. Discuss the force it took to move the output. Here is a video on the outcome of the exploration.  Compare the properties of pegboard, cardstock and cardboard as materials for making mechanisms. (See the video)

Outcome

• It is easier to push the output when you push at the end.
• The closer to the fixed pivot that you push on the output link, the more force is needed to push the output.
• The cardstock strip buckles easily.
• A shorter cardstock strip  (the distance from where it is held to where it applies force is shorter) can exert more force without buckling.

4.      Whole-class meeting: transfer pegboard mechanism to cardboard and cardstock.  Demonstrate how students can transfer their mechanisms from pegboard to cardboard and cardstock.  Here are instructions to print out and a video.

5.      Students work on MechAnimations

6.      Whole-class discussion: listing issues. Students discuss any issues in the making of MechAnimations.  Examples of issues might be:

• Parts are too hard to move;
• Input crumples when I push it;
• Pieces get in each others’ way;
• Paper fasteners get hung up on each other;
• Outputs don’t move in the direction I want them too;
• One output moves further than the other.

The solutions to most of these have been presented in this and previous classes.  Other students may be able to provide solutions.

Troubleshooting

Here are some troubleshooting issues: