Mr. Meehan’s class was tasked with creating a truss bridge model by using the following process:
Objective: To create a specific type of truss bridge model that is proportional to drawings provided by Mr. Meehan
Research: Research will be needed to determine the details of the truss bridge to be modeled.
Materials: Coffee stirrers, low temp hot glue, and ruler, pencil and paper.
Process:
1. Students will choose a specific type of truss bridge assigned per research supplied by Mr. Meehan.
2. Bridges will span 52 centimeters. The scale factor is 1:10. This means 1 mm in your drawing equals 10 mm in your model.
3. Students will create architectural drawings which are the same scale as their model. They will acquire information from the research drawings using the 1:10 scale factor. These drawings will have a plan view, an elevation view, and a longitudinal view (top view, side view, and down the middle view).
4. Students will use these plans to construct their model out of wooden coffee stirrers and low temperature hot glue.
5. Students will estimate the number and cost of materials to be used.
6. Students will acquire materials needed for construction from Mr. Meehan.
7. Materials will cost a set price. Additional materials will cost more, so make sure your estimate is very precise.
8. Students will start building. Refer to your drawing to make sure it is precise. Bridges not built according to plans will receive no credit.
9. When bridge is complete, bring it to the testing area.
10. Bridge will then endure weights placed in the center to test its strength until it breaks.
11. The bridge that endures the best cost to weight ratio wins.
To assist parents in understanding how the Common Core State Standards correlate to classroom work, we have included the standards that were assessed for this project.
Mathematics 6.3d – Students used ratio reasoning to convert measurements. Students increase scale of a thumbnail drawing of a truss bridge to actual model size. Students will also use equivalent ratios to come up with a unit rate for cost to weight ratio once bridges are completed and tested.
Geometry 6.4 & 6.5 are utilized during plan drawing and construction of bridges. Students are persevering to solve three dimensional problems, attending to precision when measuring, cutting and gluing bridges.
Engineering Standards – Students who demonstrate understanding can:
MS-ETS1-1. Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
MS-ETS1-3. Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.
