How does a bridge work? Here's a simple activity for kids that demonstrates the principles that keep bridges standing. All you need is a bowl or plastic container, a small sheet of paper, and a few pennies (or a few small toys). Ask your child or children how they might fold the paper so it would bridge the container and hold one or more of the plastic toys. I found the solution to be completely unintuitive, so if the child looks totally lost, show them one possible solution [above] and then let them experiment with other designs to see if they can figure out why some work better than others. In the Discovery Room of Boston's Museum of Science, where we came upon this activity, an engineering student let us flip through books with photos of bridges, so we could get some ideas about how to fold our piece of paper. A Google image search would work just as well: point out how the trusses of some bridges are made up of triangles to help them support more weight.
See more Museum of Science activities here.
For a more in-depth understanding of bridges, including an introduction to the forces of compression and tension, visit our Bring Science Home page.