Balsa Bridge
By Garrett Boon on May 25, 2006 - Modified April 20, 2011
This balsa bridge was built by some students of mine for a Science Olympiad competition. It spanned 14 inches, weighed 8.1 grams, and held 29 pounds. That puts its efficiency at 1630.
This photo makes the bridge look a little lopsided. That wasn’t the case, however.
Here is a photo of where the bridge broke. Click the picture to get a really good close-up.
Can you tell me the differance between the span and the length of a bridge?
The length refers to the measurement from one end of the bridge to the other. The span refers to how much of the length is suspended over air. For instance, my model bridge might be 18 inches long, but 1 inch on each side rests on blocks. Thus, the span is only 16 inches.