We'll be taking a look at some famous shaking structures then building our own suspension bridges - - and seeing which one can withstand the greatest weight.
(from our Fizz Boom Read Summer Program (For students entering grades 1-5) )
As children arrived: had a bunch of bridge & engineering books out for kids to browse..
Opened with this: “Engineers are problem solvers…so today we are going to be engineers and design and build bridges. Here’s a true story of how one man figured out how to make a very unusual bridge in a very unusual place..”
Showed The Man Who Walked Between the Towers* by Mordecai Gerstein (since we were a large group, watched the Weston Woods DVD version rather than reading the book.)
Talked about how the tightrope is a simple bridge -- illustrating tension (skyscrapers were anchoring cable on either end) and compression (the weight of the cable “dead load” and the weight of Philippe “live load”) pressing down.
Demonstrated this by having two kids pull on opposite ends of a rope (tug of war style) and pushing down on the rope with a toy car.
Showed pictures of three main types of bridges: span, arch, and suspension – had drawn these beforehand on a whiteboard based on images on p. 17 of Bridges! Amazing Structures to Design, Build, & Test by Carol A Johmann & Elizabeth J Rieth and pointed out tension & compression in each structure…several kids knew how the keystone worked in an arch design.
Talked about how they were going to be engineers today – “Nearly everything we use has been engineered…including roller coasters, smart phones, running shoes, and even ways of keeping food safe. But engineering is called “the stealth profession.” That’s because engineers work behind the scenes. We hardly ever hear about the talented but “invisible” engineers who devise many of the creations on which we all rely.” – from Bridges & Tunnels by Donna Latham
Showed this diagram of the engineering design process.
Distributed thick books (to use as riverbanks/anchors) and pieces of paper and had kids experiment with different ways to make bridges from one piece of paper (no cutting, gluing or taping allowed, but they could try arches & folding – fan folding made a very strong bridge). This was a good activity but took too much time from our one-hour program so I would omit it next time.
Talked about parts of suspension bridge:
Explained that they would divide into groups of 3-5 to create their own suspension bridges and see how strong they were (idea based on the plans from the wonderful ndolan’s http://cheshirelibraryscience.wordpress.com/2012/10/23/g3-program-15-bridges/ and PBS’s Fetch episode: http://www.pbs.org/parents/fetch/activities/act/act-whatgives.html)
Challenged them to design & build one using the rules below:
After bridges were built, piled books on to test the bridges.
(Since I had some younger kids (5-7 year olds), I also offered the option of building bridges using our straws and connectors kits.)
Good program but we were a little tight on time today – would love to do it again!
* thanks to http://thriveafterthree.com/2014/07/14/tower-building-with-the-school-age/ for the idea of using this book!
Reading Rainbow: Tar Beach -- shows how workers maintain the George Washington Bridge (suspension)