1. Engineering Design: Bridge Building Michael Starr 1, Tamara Jonson 2 1 College of Engineering, University of Cincinnati, Cincinnati OH; 2 Withrow University High School, Cincinnati, OH Abstract Activity State Standards Assessment Results & Feedback Acknowledgments Reflections Identify members of a truss system as being in compression or tension and it is possible for some members to experience no load. Use trial and error for improving the design of a supportive structure using both physical and computer models. Use basic drafting skills to create a scaled planar drawing of simple structures. Work as a group on an engineering project and complete a bridge structure from design conception to completion. Ohio Standard: Mathematics Geometry and Spatial Sense: 11-12 Benchmark A: Use trigonometric relationships to verify and determine solutions in problem situations. Mathematical Process: 11-12 Benchmark I: Communicate mathematical ideas orally and in writing with a clear purpose and appropriate for a specific audience. Ohio Standard: Science Physical Sciences: 11-12 Benchmark D: Apply principles of forces and motion to mathematically analyze, describe and predict the net effects on objects or systems. Scientific Inquiry: 11-12 Benchmark A: Make appropriate choices when designing and participating in scientific investigations by using cognitive and manipulative skills when collecting data and formulating conclusions from the data Project STEP is funded through NSF Grant # DGE058532. Prof. Anant Kukreti for his guidance as my STEP advisor. Andrea Burrows for taking photographs of the activity. I had hoped to teach the students about all the aspects of a design project starting with brainstorming and research, then figuring a budget based on a finalized design idea decided upon by the whole group. They would have to compare their original budget to their final cost of construction. What happened was students did not understand nor did they want to put much effort into making a budget. Being there only 2 days a week made it hard to get them to do this on their own. I think a good approach would be to one day use an example bridge and go through with the class how to calculate a budget for building that particular bridge, then the next day letting them do their own budget. If you are assigning a cost to materials for budgeting purposes setup a good system for a lumber yard or whatever, because I had trouble keeping track who had taken what even with a table due to my limited availability during the week. Though bridge testing was never done, myself and the students seemed to have gained some insight from this lesson. Initial Activities: Learning About Truss Systems Objectives Bridges have been essential for transportation and moving of people and goods throughout the history of man. Means of crossing waterways have been practiced since the dawn of civilization, as water is essential to life. The advent of bridges allowed easy access for people on opposite sides of rivers and waterways to conduct commerce, exchange of ideas and many other activities that have accelerated the development of technology in the human race. The process of working with each other to accomplish a task aimed at improving the living of humans is the essence of engineering. By working in groups to design the most structurally efficient, lightest and cost effective bridge the students will be engaging in the most fundamental of ideals of engineering. Pre/Post Assessment: Activity where students built cubic structures out of tooth pics and observed how cross-members served as support beams to reinforce the structure Students used a computer simulation program to draw the given structures in order to find the state of stress in the circled member as well as the value in that member as well as the other members of the truss system. Students learned basic drafting skills in order to draw a 1:1 scale drawing of their bridge design so that assembly could be done directly on top of their drawing, with wax paper down of course! Working in groups students made their designs come to life by assembling their bridges using pine dowel rods (round and square) and basal wood. Note: Poor time management from both the teacher/fellow and students as well as general lack of motivation led to the bridges not being done in time for the competion and the bridges were never tested :( Series of questions aiming to determine the students ability to recognize when a beam is in compression or tension given a set of parameters Students averaged a score of 89.4% on the video questions Average score on pre-assessment was 58.3% with a low of 15% and high of 95%, no post assessment done because students did not complete their part of the lesson in time.