The Bridge Building Contest

In this experiment your will have an opportunity to apply what you have learned about force vectors. The objective of this experiment is to build the strongest bridge possible given a set of predetermined constraints. During the double period lab session you will construct the bridge and the next day each group will give a short presentation on the design and then test the maximum weight that the bridge can hold. The best bridge in each class will receive 10 extra credit points.

The rules for the bridge building contest are as follows:

1. You may only use a maximum of 18 straws and 18 pins. You may bend the pins and cut the straws but no other material may be used.
2. The bridge must be three inches wide and span a distance of ten inches, which is longer than one straw.

The Presentation

(5 points)

In the presentation summarize the design and point out straws that supply compression ( a force which is pushing) and tension ( a force that is pulling).

The Grade

For each 100 grams that the bridge holds a group will earn 1 point. The maximum points is 15. The presentation will be graded for organization, clarity, and content on design and forces. The best bridge in each class will receive 10 extra credit points.

Total points: 20.

Hints

1. The bridge must span 10 inches so make sure that the bridge is longer than that so it can rest on the ends.
2. The handout on types of bridges can help in deciding the design but remember that your bridge will be very limited in material: 18 straws.
3. Leave room on the bridge for the pans that will hold the weights.
4. Make sure that bridge is even and will not prematurely tip over.

Questions? Comments?
Michael Gilmore