Lee Schierer
06-23-2010, 11:55 AM
Recently my granddaughter, who is in fifth grade, called and asked if I could design a bridge for her for a project/contest at school. I made a layout on autocad and suggested some simple design procedures to follow, such as using the flatest sticks she could find, doubling up all pieces to increase glue joint area and roughing up the sticks with sand paper for better glue grip. Her bridge was one of two that survived the final test. She took all of the attached photos.
Guidelines for the contest: bridge span between 20-24". Bridge width to accommodate two "Hot Wheels" type cars side by side. No more than 100 popsicle sticks. Adhesive must be Elmer's white glue or Elmer's wood glue. No coatings on the outer surfaces. No road surface is required.
Emily's bridge in Round Two testing. Round one: four red bricks. Round two: one concrete block and two bricks, Round three: two "concrete blocks." Emily's was one of only two arched bridges, and was the only bridge to double or triple up the main structural components.
Various teachers stood on the block on top of the three remaining bridges. Eventually Mr. Drake (200+ lbs) stood on the block (so the weight was at least 250#), and one more of the final three bridges failed. Emily's survived!
She called me as soon as she got home and was very excited with the results and plans to keep the bridge in her room.
Guidelines for the contest: bridge span between 20-24". Bridge width to accommodate two "Hot Wheels" type cars side by side. No more than 100 popsicle sticks. Adhesive must be Elmer's white glue or Elmer's wood glue. No coatings on the outer surfaces. No road surface is required.
Emily's bridge in Round Two testing. Round one: four red bricks. Round two: one concrete block and two bricks, Round three: two "concrete blocks." Emily's was one of only two arched bridges, and was the only bridge to double or triple up the main structural components.
Various teachers stood on the block on top of the three remaining bridges. Eventually Mr. Drake (200+ lbs) stood on the block (so the weight was at least 250#), and one more of the final three bridges failed. Emily's survived!
She called me as soon as she got home and was very excited with the results and plans to keep the bridge in her room.