Lesson Plans
Lesson 1
In the first lesson, students will learn some background knowledge about bridges. Each student will be given a copy of the Basic Bridge Information and the Famous Bridge sections of this paper. Then they will select three famous bridge names. (No two students will have the same bridge) They will be assigned to do the following: sketch the bridge, give the date constructed, the location, the type, the forces of tension and compression, and the materials used. Students will present each bridge on a 12"x 18" poster. A time line from 2000 B.C. to the present will surround the classroom. Students will order chronologically these posters on the time line. Conclusions will be drawn as to when types and materials became available by discussing the time line. Students will then be asked to create a flip book for a specific bridge (see appendix). These books will be an explanation of some of the bridges found on the poster time line.
Lesson 2
In the second lesson students will expand their knowledge of bridges by selecting a favorite subject activity. The scientific student will study foundations and simulate how cofferdams were first constructed by the Romans. That student might prefer to demonstrate how keystones in arches work. The mathematics student may wish to graph the loads various paper beam bridges will carry. The artistic student will enjoy selecting a famous bridge to paint. The history enthusiast will enjoy studying which bridges played a significant role in a battle. The finished products will be shared with the class. Each student will describe what they have done and their results. The following is an individual description of each project.
The cofferdam will be constructed by placing a donut ring of clay into a pan with one inch of water. Then six inch dowel rods will be pressed into the clay adjacent to one another forming a circle. Next, a second ring of dowel rods or pop cycle sticks will surround the first ring. Wedge a plastic bag(s) in between the two rings. For added stability, taping the two circles might be necessary. Using a turkey baster, pump the water out of the inner circle. This was the technique the Romans used to build piers for their bridges. 48
To demonstrate how a keystone works have the student take a swimming noodle and bend it to form an arch. Tie the ends together to maintain this shape. Looking closely, the compression on the interior and, the tension of the outer part of the arch are visible. The student will first mark and then cut the pieces of the noodle into an arch. (With teacher or parent supervision using a knife). Now for the challenge! Try to put the pieces back together on a flat surface. When the keystone is in place, lift the arch.
For the mathematics student to demonstrate the relationship between span and load, have them complete the activity for lesson 2, Paper Bridges in the appendix. Once they complete the worksheet have them graph the results. The artist student may paint any bridge of their choice. The same information presented in the poster activity in lesson one should accompany this project. The history student may construct a diorama of a famous battle. An oral presentation should include the basic facts of the bridge as well as the circumstances of the battle.
Lesson 3
In the third lesson students will construct a bridge. They will choose one from the failed bridge section of this unit. Prior to construction they will find the location using a map and "google earth". The type, length of span, body of water crossed, environmental factors, and history will be required in a report that will be presented at the conclusion of the project. Not only will each student select a bridge to study, but also they will recreate or diagram its impairment. In this part of the lesson the student will learn to appreciate the technological difficulties that have been overcome by giving them an inkling of the difficulties faced. Materials such as: balsa wood, pop cycle sticks, dowel rods, tag board, wire, fishing line, and glue guns will be provided. Additional materials may be brought from home. Each student will draw a blueprint of their bridge to scale. Using this as a pattern, they will then cut out the blueprint and trace the components to construct their bridge.
Lesson 4
In this lesson students will research bridges in their state or area. Students will make a list of which bridges are classified as structurally deficient or structurally obsolete. Have the students write the local department of transportation to inquire when bridges will be repaired or replaced. Teachers might even wish to have their student write local government leaders in support of bridge maintenance or replacement. Students will be asked to keep a log of all contacts and responses. Also included in this list will be a first hand observation of students who have witnessed bridges being repaired or constructed.
Many students today have never constructed a project that is not a kit, or model. By using everyday materials, students will learn how to solve problems while learning about bridges. After the students have completed this unit they will display their bridges and their parents will be invited for a culminating activity. Each student will describe the bridge they have built, and tell how it was constructed and the facts described in lesson three. By chronologically ordering their projects, the technological development of bridges will be reiterated as with the lesson one time line. Additionally, the activities in lesson 2, and logs from lesson 4 will be on display.
With this unit students will gain an understanding of the challenges that bridges have presented in the past as well as in the future. Through research and reasoning they will perceive that bridges in the past may have failed because of lack of knowledge. Today that knowledge is available. The obstacles today are environmental issues and the state of our aged bridges. By researching famous bridges and bridges that have failed and by pursuing hands-on activities about bridges, they will gain insight into the evolution of technology that bridges have endured. Students will learn that bridges are not only the art and science of connecting communities; they will see that they tell the history of our achievements, not failures. We will discover how to build bridges from our mistakes.
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