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8th Grade Core
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The Bridge Builder

You have learned that gravity is a major force on Earth. Humans have had to consider the effects of gravity as they designed and built structures on Earth. In this activity, you are going to have the opportunity to design and build a bridge to support a load. Find a friend you can work with - or challenge your friend to see who can build the strongest bridge. The challenge you will have is that your bridge is to be made of dry spaghetti noodles using glue to hold them together. The object is to construct a bridge that will carry the heaviest load while still meeting some specifications. The test will be to put a load onto the bridge until it fails.


  • Spaghetti noodles
  • White glue
  • Two supports structures (tables or desks with flat tops will work)
  • Toy car or blocks of wood about 10 centimeters wide
  • Weights (books may be used)
  • Balance scale
Safety concerns: Be sure to keep all chemical safety rules. As with all science lab activities, the most important safety rule is to follow all teacher directions.


  1. You are to design a bridge that can rest on two support structures (desks or tables).
    • The support structures will be placed 30 cm apart from each other.
    • You may not use the support structures as part of your bridge.
  2. The width of your road surface needs to be at least 6 cm wide across the entire length of the bridge.
    • The width will be tested by moving a car, or a block of wood, across the entire bridge.
  3. You should not have any gaps greater than 2 mm so that the bridge appears to be solid.
  4. Include a "loading platform" at the top of your bridge.
  5. This platform is what the books or weights will be placed on.
  6. The maximum mass of the bridge should not exceed 200 grams.


  1. How did the design of your bridge compare with that of your friends?
  2. How much total weight did your bridge support before breaking?
  3. Which bridge design was capable of supporting the most weight?
  4. How realistic (like bridges you have seen) was your bridge?
  5. How important was the glue?
  6. Math time! Divide the total weight (mass) that your bridge held by the mass of the bridge! How did your bridge compare with that of your friends?

Review Science safetey rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 8th grade science core.

Updated October 24, 2008 by: Glen Westbroek

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