planning.

=Before= Before we started planning, we realized that there were restrictions our bridge needed. Thus, we created a list of restrictions we needed to check our bridge for before handing it in. =Planning= To begin planning, we decided to use a simulation instead of rebuilding the bridge over and over again. Taking Mr. Happer's advice, we used the West Point Bridge Design software (download here: http://bridgecontest.usma.edu/) and created stimulations that would be able to withstand 20 kg. As you can see from the pictures below, we weren't successful in most of them but we benefited by learning where we needed to edit our bridge thus by modifying the stimulation, we were able to come up with a simple design that we would then make a hard copy of.
 * 1) The bridge should only be build with balsa wood and glue
 * 2) The total mass of the bridge should not exceed 100 g
 * 3) No element should be wider than 1 cm nor thicker than 0.65 cm
 * 4) A 5 cm cube should pass underneath the structure
 * 5) a 40 cm long and 2 cm high board should be able to slide underneath the structure
 * 6) the bridge must be 40 cm long and should have a width of 5 cm
 * 7) the roadway must allow anything to slide through
 * 8) the criteria for the balsa wood is:

Discoveries: Throughout the process of creating the bridge, there were many new discoveries that we never could have known before. This experience has taught many valuable lessons. When we first planned the bridge, the original bridge design was highly inefficient and most likely wouldn’t have worked. Later, our group used the West Point Bridge design software to project how a real bridge would react to a truck driving across. Through this software, we discovered how bridges undergo tension and suppression in different parts of the bridge. Tension is a force that acts to expand or lengthen the thing it is acting on. This usually occurs on the bottom of the bridge that supports any cars or weight that rests on it. Compression is a force that acts to compress or shorten the thing it is acting on. This usually happens on the top part of the bridge. When using the bridge software, we could see the types of bridges that were stable, and in the software, blue meant tension, and the material of the bridge was stretching. The Compression was colored in red, and signaled the wood being shortened by the weight compressing it. Then, we made a new bridge based on a simpler design that we saw in the software. Through the software, we have learned many new physics principles, and we hope that when testing our bridge, it will be able to withstand a lot of weight.

PREDICTIONS:

Our group is conducting a experiment on the strength and stability of wood when glued into different shapes. We conducted a experiment when 3 pieces of wood of the same length are glued into an equilateral triangle, or glued together flatly like a bed. We predict that the triangle will be stronger, because triangles, especially equilateral triangles are very stable. Our group hopes to investigate this, because currently, we have no real information about why triangles are stable.