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Engineers in Training 2009
Shodor > SUCCEED > Workshops > Archive > Engineers in Training 2009

Today's class was about trusses. The morning began with an introduction about what trusses are and their purpose. A piece of foam was used to demonstrate this, showing how both tension and compression can occur. From here they moved on to using an applet on the computer to model a 2-dimensional shape, showing where tension and compression occurred and how much force was applied to each part of the shape. Initially they modeled a triangular shape, using forces going downward, upward and to the side. Before each test they tried to predict where tension and compression would occur and at what magnitude, comparing the predictions with the actual results. From here they moved on to modeling a rectangular shape to demonstrate how unstable this shape was on its own and how it can be reinforced using additional connectors to create triangles within the structure.

Once this concept was introduced they moved on to modeling more complex shapes and adding loads to them pulling in multiple directions. This first part of the class ended with a competition to create the best structure for distributing the load. Each group had to model with a maximum of 25 connectors and 14 joints and have it take a downward force of 100 and a sideways force of 20. The structure that had the lowest strain on any one part would win. Most groups managed to get below 50 units of force on any one part with the winners having 29 units.

For the next part of the class they revisited a previous lesson with electrical resistance. They used tools for measuring electrical charge called multi-meters to check the exact resistance created by a 10k ohm resistor. They found that in most cases the resistance was actually not 10k but instead somewhere between 9.5k and 10.5k. After plotting this on a box graph they also found that the average resistance of all the resistors in the package is much closer to 10k than the resistance of each individual resistor.

During the last part of the class Jeff Krause came to the class as a guest speaker and introduced the basics of biomedical engineering to the class. With him, they visited some of the basic uses of this growing field. At the end of the class, he showed a video called the "Inner Life of a Cell" to show how complex the cell and molecules that this field works with are.