Bridges

ag_science_bridge
ag_science_bridges_arch

Arch Bridge

ag_science_bridges_span

Span Bridge

ag_science_bridges_suspension

Suspension Bridge

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Truss Bridge

Learn about types of bridges and construct an example

K-6

Bridges have been built to span rivers, gorges, straits, and valleys as civilization has progressed.  Bridges also give evidence of the great creative ability in humans and their ability to develop skillful engineering feats.   Recorded history tells us that stone vault bridges were constructed as early as the 2nd millennium BC. Primitive bridges constructed of twisted vines, logs, and stone vaults have been found in South America, Africa, Kashmir, China and Japan.

Bridges are basically one of four major types: span, truss, suspension or arch. Each of these types uses different techniques to support the enormous weights that bear down on its elements.  The Romans, master bridge builders, applied civil engineering on a large and grand scale with the use of cement, cofferdams, the arch, and systems of workers.  Following the decline of the Roman Empire, the art of bridge building fell dormant through the early middle ages in Europe until the early Renaissance, while it flourished in Asia.  Many wondrous bridges were constructed during this time that expanded on the Roman models and lay the foundations for the marvelous structures of today.  The masonry bridge reached its heyday in the 18th century and gave way to structures being constructed of iron.

Preparation
No special materials are needed for this activity.

Procedure
The teacher should hold classroom discussion on a brief background on bridge construct and types.  Simple illustration can be used to explain the different types.  A reproducible sheet is provided that assists with this.

The student will select a type of bridge to construct and lay out a basic model.  Younger children should be encouraged to use basic shapes and construct simple structures.  These can be as simple as a plank crossing a stream or use of an arch between two points.  Older students should be encouraged to construct their bridges from component pieces put together.

Students should experiment with the different shapes to select the best components with which to build their bridges.

Evaluation
Evaluate the student's grasp of the function of bridges and how they are basically built.

Assign a written description with the 3D scene to assess student's understanding.

Have students describe their bridge scene to the class or smaller groups.

Group work is encouraged with the construction of more complex structures.

Extensions
Construct a collage of bridge types.

Have students research major bridges of the world and put together a unit pictorial book with the 3D scene printouts.

Visit websites that show photographs of major bridges.

Make a model of a bridge type.

Tips
The Copy tool is very valuable in this activity.  Use it to reproduce basic component pieces to build a larger unit. The Turn tool is also helpful when building symmetrical pieces.

Links

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