Super Bridge Grade 7 Science Structures and Mechanisms

- describe, using their observations, ways in which different forces can affect the stability of a structure - demonstrate awareness that the effect of forces acting on a structure under load depends on the magnitude, direction, and point and plane of application of the forces; - identify forces within a structure that are affected by forces outside the structure

  A Link to Learning web-based student learning activity     www.linktolearning.com

This activity is based on the web site;
http://www.pbs.org/wgbh/nova/bridge/

Go to the Build a Bridge section, survey the sites and then investigate each bridge type.

1. What unique characteristics do arch bridges have? __________________________________

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2. How is the weight of an arch bridge distributed? ___________________________________

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3. What type of force is acting on all parts of an arch bridge? ___________________________

4. What distances do modern arch bridges typically span? _____________________________

5. Why is the construction of an arch bridge "tricky"? _________________________________

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1.What unique characteristics do beam bridges have? ________________________________

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2. Explain what a beam bridge consists of and how weight is distributed. __________________

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3. What two types of forces are active in a beam bridge? _____________________________

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4. What maximum distance can a beam bridge span? ________________________________

5.What is a "continuous span" bridge? ____________________________________________

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6. What is the major drawback of continuous span bridges? ___________________________

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1. What unique characteristics do suspension bridges have? ___________________________

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2. How is the weight of the bridge carried? _______________________________________

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3. Why is steel used for the cables? ____________________________________________

4. What is the biggest concern regarding the stability of these bridges? Explain. _____________

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5. Give an example of a suspension bridge that "failed" and explain the cause. ______________

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1. How are cable-stayed bridges similar to suspension bridges? _______________________

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2. How are cable-stayed bridges different than suspension bridges? ____________________

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3.What spanning distances are cable-stayed bridges often chosen for? ___________________

4. What two factors make cable-stayed bridges preferable to suspension bridges? __________

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Select the non-Shockwave version unless you know that the Shockwave plugin has been installed on your computer.

Record your selections as well as the correct selections.

Site 1 A 5,000-foot span across an ocean bay where huge ships come and go.

Your selection _____________________ Correct selection ___________________

Site 2 A 120-foot span across a freeway.

Your selection _____________________ Correct selection ____________________

Site 3 A 1,000-foot span across a river busy with barge traffic.

Your selection _____________________ Correct selection ____________________

Site 4 A 700-foot span across a deep canyon gorge.

Your selection _____________________ Correct selection ___________________