Designing and Building Bridges: Second Class.

The boys in second class were very busy this week. They worked as engineers to explore the basic physics of bridges. Through experimentation the boys learned which shapes were the most structurally strong. They also learned that many factors need to be taken into account in engineering and building.

Background Research Work

We looked at different types bridges from around the world. We discussed the shapes, designs and materials used in Beam, Arch, Truss and Suspension Bridges.

Building a Simple Beam Bridge

We made our Beam Bridges by using copy books as beams and cardboard as the deck. Using rulers, we measured the length of the deck of our bridges. Following that we tested the strength of our bridges by putting 1 cent coins on them. We made predictions on how much money the bridges would hold. We recorded our results. We concluded that the closer the beams were together, the more money they could hold.

Construction of a Strong Bridge.

We worked in teams to construct bridges that would hold at least 4 toy cars. Our first step was to test shapes made out of cardboard to see which shapes would be the strongest to use in our designs. We made predictions before we tested. We discovered that the triangle was the strongest shape.

The materials that we used to build our bridges were cardboard, triangular shapes, plastic cups, straws, coloured card, Sellotape, glue, scissors.

Working in our teams, we first planned out the design of our bridges. Next, we used plastic cups as beams and the triangular cardboard shapes as supports to build the bridges. We tested the strength of our bridges by putting toy cars on top. Every bridge built was able to support the cars. Using rulers, we measured the length and height of the bridges. We recorded our results. We concluded that adding the triangular shapes or extra beams made the bridges stronger.