He has to build a toothpic suspension bridge to hold a toy train car moving across this bridge with a 4.5 lb brick across the bridge and hold 2 bricks that weight 4.5 lb for 10 seconds without it breaking. It has to be level, stable, and clean The bridge has to be 16" long and 4" wide. He can use Diamond flat toothpicks, goodcook kitchen twine, and elmers's white glue. Extra points for fewest number of toothpics used. Any good websites to mimick and use, or any ideas from the geniuses on this site would really be helpfull. Thanks in advance.... Tim
I tried sketching my concept for you, but it's taking a little too much effort for 12:07am. From your description, it sounds like there's no limit on the twine, so I would definitely center my design around that. How is it anchored on the ends? Is that part of the design, or will it be held down in some other way?
haha, I did this back when I was in middle school. I built a bridge, that have a lot of trusses on the bottom and top of the bridge with the smooth pathway in the middle. That's bigger than mine.
How fancy do you want to get? If I were doing that today, I'd put the twine and toothpicks in a blender with hot water and elmers glue and spread it over a wooden arch jig covered with wax paper and let it dry. It might be a spectacular failure depending on how well the glue holds. Hand weaving the fibers would work better but where is the fun in that? Whatever you do, try testing on a smaller scale to see if what you're doing is going to work.
the strength will be int he tie-ins ont he ends of the bridge. What can he tie it off too? Use only one pillar and make it a good one that can take compression. Make the twine thicker to get good strength.
I would suggest the "don't put it off until it's so late your brother has to ask for help on clutchfans" method. seriously, overlap the toothpicks secured with glue, wind tight with mondo wire-age and the sky's the limit, eh?
I built a KICK ASS toothpick version of The Alamo for Texas History back in the 7th grade. Not just the chapel, either – I’m talkin’ the whole fort. If I recall correctly, I got an A. The best part was burning it down with a magnifying glass after I got it back. Ah, to be 13 again…
No hot glue? You sure you can't use wood glue either? I made one that was int he top few for a physics class. The winning one had its support based off of a pyramid/triangular joint design: basically the weight was more evenly distributed that way versus a simple box/square design. Here's a couple of links for ideas: http://www.pisymphony.com/toothpick/toothpick1.htm http://www.pacificsites.com/~jade/ToothpickBridgeLinks.html
Hey Fatty, what generalizations are you trying to make? Not all women are building babies inside - some of us just have empty vaginas.
True unhelpful story: I had to do this in junior high and waited too long to do a real bridge. So I made a big log of toothpicks and covered them in airplane glue (friend of family was a pilot). So it was completely indestructible. At the contest to see how much weight they could hold, the judges eventually put so much weight in the bucket that the bridge bent until it could fit between the gap. Once it squeezed through, and the weight fell, it snapped back into it's original stiff log shape. The judges huddled and decided to disqualify the bridge as it did not support the weight. It's good that the contest mentioned in the OP has more rules than mine did, so that goofballs can't use airplane glue on a toothpick log.
http://library.thinkquest.org/J002223/types/types.html Check out this one in Monterrey: http://www.flickr.com/photos/carreon/542477384/sizes/l/ . What about THIS MONSTER that's what she said: http://en.wikipedia.org/wiki/Millau_Viaduct ?? http://en.wikipedia.org/wiki/Bridge all types of bridges.
use statics to find the reactions at the supports and then use the method of sections to find the internal forces in the truss design...then you can deside where to add more toothpicks
