dholdgreve wrote:It sounds like you may have misinterpreted what I meant when I said that the cyanacrylate glue can get old and brittle... I meant that this can happen after he bridge is assembled, the glue has dried, and is now exposed to the atmosphere... Not that the shelf life of a bottle is only 3 to 4 months... I believe that, kept properly sealed, a bottle of glue is viable for a couple of years or longer.
We use a scale that goes to the hundredths... I think going to the thousandths of a may require a dome, or some sort of protection to be accurate. I try to get the builders to document every single piece that goes into a bridge... Just quickly weigh it, then write it down on their template, next to the piece. At our Regionals, they only weighed the bridges to the nearest tenth of a gram, which IMHO is not accurate enough. When bridges were "in" several years ago, several teams tried an arch design, but I do not believe the arch has near the potential efficiency as the tower type bridge that is so popular this year. In 2005, I believe the winning mass in Div B Ohio was about 6.23 grams... This year I'm sure it was under 4 grams... This just goes to show how much more competitive Science Olympiad has become.
Actually, I did understand you correctly - I was just extending on your point and asking a question from there. Just curious whether my glue had an effect on it because sometimes the supporting compression members fell out after testing. I guess it wasn't dense enough?
I always wrote the weight of each pieces on the wood itself... Wouldn't it be less organized to write it next to the template, since you will need to keep the template themselves? When I go back to the bridges I tested, I can always see the weight of the bridges and make easy note of each variables. I would also always use the same template over and over until I have to change my design.
I always see every teams attempting the arch designs because it is efficient to some extent -- until they discover a more efficient design, although I have not attempted them because I hear how inconsistent
they are for each testing. I believe the score in division C is around 1600-1800 for arch bridges, whereas the tower-like design has the potential to go above 2000.