Physics of Bridge Building

Students will answer the question: How does Mass affect force in physics? and What makes a good bridge?
In this lesson, students will be given straws, clay and pins and they will have to build their own bridge. They will follow the scientific method to identify their variables, set their control and write their own procedure with the given materials. Students will need to build their bridges at least 20 centimeters high and 15 centimeters long. Students will work in groups of 4. They will need to make a hypothesis about how much mass their bridge will hold. They will then need to do research about bridges and how they are built. Then they will build their bridges. When their bridges are completed, they will able to test them using different masses. They will film their bridges being tested on a flip video camera. Once they get the total mass that the bridge will hold before breaking, they will then calculate the force the bridge will hold. THe next step will be for students to decide with their group which material they should increase 2x to make the bridge able to hold more force, the straws, the pins or the clay. They will then calculate the force using the physics formula F=MxA to see how much force each bridge can hold. Students will then be asked to choose which one of their materials they would like to change to make the bridge stronger. Then the students will construct another bridge using the added materials and test the bridges again to see how much mass each one can hold. Then they will calculate force. Students will enter their data into google docs using an ipad. Students will then make a website using Google Sites to post pictures of their bridges and write about what they learned from doing their experiment.