How can I make this engineering/science experiment more complex?

Question

I tested which truss bridge, out of 6 of the most common, would hold the most mass/pressure (using multiple different sizes of bricks). I made the bridges out of k'nex and conducted 50 trials for each bridge. I used string to lower bricks onto the bridges and did so until the bridge broke. After it broke I would fix the broken links and repeat the trial. I also have pictures of all the bridges after I made them on my presentation and the building/testing procedure for the experiment.

I also did research that included the history of the bridges and what truss bridges, trusses, dynamic loads, dead loads, pressure, momentum, friction, and tension were. Included in the calculations are percentage of body mass held, pressure, and technically momentum (but it was barely used). I also have down many controls, an independent variable, and a dependent variable as well as possible errors, possible solutions to the errors, future studies, and observations.

For the data, I made 6 separate line graphs (one for each bridge), a combined bar graph of the highest mass held, lowest mass held, and average, and a comparison table of the highest, lowest, and average mass held as well as the bridges' masses and their percent body mass held.

Other than scraping the project completely, what can I do to make this more complicated? I need 10th through 12th grade level and I know what I've done won't cut it, but it's too late to change my project completely. Thank you in advance!

Answer 1

This sounds plenty complicated as it is. The problem is that many science teachers are biased against K'nex, thinking it is a children's toy. Frankly, this is not sensible, but you are stuck with this prejudice! All you need to do is use 1/8 inch wooden dowels and epoxy to build the trusses, and repeat the experiment. Of course you get only a single trial for each bridge, but real engineers have the same problem.



You could also use stress analysis software such as Solidworks to predict the strength of the truss, and see how close the prediction is to the experiment. There is a substantial learning curve to using stress analysis software, but the skill will be useful for the rest of your life.

Answer 2

The only thing you need to do is make sure your experiment at least broadly follows the scientific method. It should have a hypothesis - which bridge type will hold the most (or the most percentage of self weight), and why. You've already examined the variables and sources of error. You've got calculations attempting to numerically explain/predict results.



Write a kick-*** report to go with it, a good experiment means nothing without great documentation.

Answer 3

Just in case someone comes back to this years down the line, I received a first award at Regionals and a second award at States with this project for PJAS. :) Have a good day!

Answer 4

You can make it more complex y including windage. Look at the Tacoma Narrows Bridge as an example, and what they did for the San Francisco bridge later to avoid collapses because of the wind's affects on the bridge structure.

Answer 5

Why do you think this won't cut it? This is for 10th >12th not a PhD.