Group ____________________________________________
Physics Bridge Competition
Your team’s task is to build the strongest bridge made out of only wooden toothpicks and white Elmer’s
glue. The bridge must span a 12-inch gap and be wide enough to fit a toy car. You may use as many
toothpicks as you need, but less weight is better.
For testing, the bridge will be loaded at the center. A cup will hang from the road deck and will be
progressively filled with sand. When the bridge fails, the mass of the cup will be taken and plugged into
the following equation:
Mass held/(mass of bridge)2
Examples:
A bridge holds 26 kg and has a mass of 24 g
26000 g / 576 g = 45.139
A bridge holds 26 kg and has a mass of 36 g
26000 g / 1296 g = 20.062
A bridge holds 14 kg and has a mass of 13 g
14000 g / 169 g = 82.840
A bridge holds 45 kg and has a mass of 35 g
45000 g / 1225 g = 36.735
A bridge holds 45 kg and has a mass of 24 g
45000 g / 576 g = 78.125
The highest overall score will win the competition.
1. Begin by developing a design for your bridge. Consider the common shapes for bridges and draw
your bridge concept in the space below:
2. You will not be able to build your entire bridge in one sitting (some parts require the glue to be dry
on other parts). Create a step-by-step action plan for construction of your bridge in the space below:
Scoring
Final bridge mass
__________ g
Bridge Score
Mass held
__________ g
___________
Analysis
1. Why did you choose to design your bridge the way you did?
2. What caused your bridge to break? Be specific.
3. What would you change about the design or construction of your bridge if you were to do the
project again?