Popsicle Bridge Contest

Participants are to design a bridge made solely of popsicle sticks and glue. This bridge will be tested to destruction for strength.

The winning entry will be the bridge that has the highest efficiency in carrying a load applied at its center. That is, the winning bridge will be able to hold the largest load (the maximum load recorded at the point of breaking) proportionate to its weight. This efficiency will be calculated using the formula (applied load / weight). The maximum load will be calculated using the apparatus in the diagram below. A 6 cm diameter shaft will apply a load vertically onto the bridge at the center of its span. There must be sufficient room to allow this shaft to reach the deck/roadway surface. This shaft will be connected to a bucket of sand hanging below. Sand will be added to simulate weight until the bridge’s road deck flexes 3 cm below its original height or breaks (whichever comes first). Each bridge will be checked by judges for adherence to the rules below prior to the competition. Those entries not meeting the specifications will be immediately disqualified.

Rules

• Overall length must be between 65 and 75 cm.
• Height (not including supports) must be 8 to 15 cm.
• Width of the deck must be 8 to 12 cm. (It must provide space for a 6 cm diameter shaft.)
• Height of the supports must be 10 to 15 cm.
• Innermost distance between the supports must be at least 40 cm (refer to Figure 1).
• Bridge must have solid, smooth decking (roadway surface).
• Center of bridge must be designed to allow for testing with the apparatus described above.
• No more than two bridges may be entered per contestant (or team).
• Only popsicle/craft sticks (may be cut down to any length) and Elmer’s Glue-All glue may be used. No solid wood blocks are permitted.