Bridge Engineering

Second grade scientists have been studying bridges this fall, learning how different types of bridges work and the structural elements that contribute to the strength of each bridge design. 

Students started the unit by designing and building a bridge out of popsicle sticks and glue to assess what they already knew and tested the structures to see how much weight they could hold. Then, they started an in-depth study of specific bridge designs. They learned how beam bridges, truss bridges, arch bridges, and suspension bridges work and explored the concepts of tension,  compression, and force. They discovered that triangles are the most robust shape and are often used in bridge designs to help distribute weight evenly. At the end of the unit, students had the chance to apply what they had learned by taking another crack at constructing a popsicle bridge. “They’ve learned about tension and compression and how engineers have built successful bridges around the world,” says Second Grade Teacher Jessica Nichols. “Now, can they build a successful bridge that bears more weight than the one they did at the beginning of the fall?” 

Second graders also did an additional design challenge working in groups to build a popsicle stick bridge using one of the four designs they studied. Then, the class incrementally added weight to each bridge to see how much it could hold and which design was the strongest. The truss bridge easily came out on top, with one group’s structure holding a whopping 65.5 lbs before it finally cracked! When each bridge eventually broke, students spent time analyzing where it had failed and making connections to the strengths and weaknesses of each design.