As the ground shakes, so do buildings on top of the land. It is often said that earthquakes don’t kill people, but falling buildings do. Older, unreinforced brick buildings and woodframe buildings can collapse during an earthquake. Reinforcing these older buildings helps to strengthen their structure. We can explore the strength of buildings by using five straws and some tape.
Step 1. Make a square frame by taping four straws together. Hold the frame upright on a flat surface.
Step 2. Hold the bottom straw in place with one hand. Push the top straw to the right with your other hand. Push as far as you can without breaking the frame.
Step 3. Tape the fifth straw horizontally across the middle of the frame. Repeat step 2.
Step 4. Untape the fifth straw and retape it diagonally across the square from corner to corner. Repeat step 2. Which frame is stronger: the four-straw or the five-straw frame? Why? How does the diagonal placement of the fifth straw affect the frame’s strength?