Activity I: Strength Test of a Beam and Arched Bridge
Objectives
The students will build a beam and arch bridge. Then they will see which of the two bridges will hold the most weight.
Materials Needed
2-4 bricks per group, corrugated card board, weights
Procedures
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(1) Place two bricks 20 cm apart.
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(2) In order to make a higher structure, place the second set of bricks on top of the first layer of bricks.
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(3) Place a piece of corrugated cardboard between the two bricks.
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(4) Gradually place weights in the center of the cardboard until it begins to sag in the middle.
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(5) Record the amount of weight the bridge held before it began to sag.
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(6) Rebuild your bridge as stated in steps one and two above.
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(7) Place an arch between the two bricks by carefully bending a piece of corrugated cardboard in the form of the arch. Make sure that it fits snugly between the bricks that are 20 cm apart.
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(8) Place a piece of cardboard on top of the arch between the two bricks.
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(9) Gradually place weights in the center of the cardboard until it begins to sag in the middle.
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(10) Record the amount of weight the bridge held.
Observations
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(1) What type of bridge did you build at the beginning of the activity?
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(2) What was the second type of bridge you built called?
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(3) What effect did adding the arch to the bridge have, if any?
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(4) Which bridge would you rather cross, why?
Activity II: Building a Strong Support
Objective
The students will build a tower with wooden coffee stirrers. Each tower will be tested to see which one will hold the most amount of weight. Be sure to point out the characteristics that made a tower weaker or stronger.
Materials Needed
Wooden coffee stirrers, glue, weights
Procedures
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(1) Break the class down into groups of three or four.
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(2) Have each group draw a blueprint of the tower that they plan to build.
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(3) Once the instructor approves the tower, have the students build the tower.
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(4) Place the towers on display in front of the class.
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(5) Place weights on the tower until it begins to buckle.
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(6) Record the weight that the tower held before it began to buckle.
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(7) Have each group discuss why their bridge buckled, and any improvements that they could make in order to make their tower stronger.
Lesson Extension
Have each group redesign their tower with the recommendations they made to improve their tower. Test each tower to see if it is stronger than the first one they made.
