Elevated Bridge B/C

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Re: Elevated Bridge B/C

Postby evbassboy13 » May 26th, 2010, 8:38 pm

nejanimb wrote:The balance at nationals oscillated a little bit too - the lowest it read for our bridge was 7.46, but they decided to keep it at 7.48 (fortunately, even those two hundredths would have left us 0.9 points behind Kansas, so I'm not bitter about it.... 7.45 would've done it though! o.O).

I do think a (load supported)^2 / mass of bridge method would skew it too much in favor of holding more weight. Minimum load for tier 1 (10kg?) would be interesting though... then it reinforces the "it has to hold a certain amount" idea of real-world structures. 15kg for max load is still good.

I'm much more curious about how the tower specs will be. I think the old towers were.... way too easy. It didn't take much to come up with a design, and they all looked pretty similar at the top, whereas designs for Elevated Bridges were hard to come up with and ended up very varied. I still think something like a Crane would be very cool, though that's very complicated. Maybe easier would be to add a clearance for towers (fairly easy) in addition to the cinched version that was added in the second year of tower's last appearance.

I wonder if there couldn't also be "bonuses" in the structure event as there are in others (like the bonus wing for wright stuff or the egg bonuses for rockets). Perhaps it could be based on the height or other interesting modifications... Or maybe that would challenge the "purity" of the event.

I agree on the (load supported)^2 / mass of bridge being too much. I think adding an additional 15% would be nice, as would the minimum/maximum idea. Perhaps it could be (2 * (load held) - minimum) / mass of bridge.

I definitely would like to see a crane event. It would be very hard to design, and Science Olympiad is all about challenging students. If I get a chance one of these days, I might draw up some rules for that... And then challenge some people on my team to design cranes. :D I'm not sure how complicated it would be - you just take the elevated bridge rules and turn them on their side (assuming you can have a base under the weight - counterweights seem a little counterproductive in balsa events).

I think bonuses would violate the spirit of a tower/bridge/boom-like event. Solid idea, but I feel like it would be really gimmicky in practice.

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Re: Elevated Bridge B/C

Postby StampingKid » May 27th, 2010, 8:28 am

I think all the towers tended to look alike because two stages were dictated by the rules. I think mandating certain design/construction parameters, e.g. a three legged vs. a four legged tower, might make it a bit harder.
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Re: Elevated Bridge B/C

Postby rjm » May 27th, 2010, 9:23 pm

The scoring system for any event should be designed to reward the preferred outcome. In developing an event, you have to start out be deciding what the event is about, what you hope to have the kids take away from it, which details contribute to the outcome that you intended.

To me, this event and the other structure events are about the students exploring the limits of all aspects structures, including design, material selection, craftsmanship, and - as evidenced by this board - development of a body of knowledge and collaboration on research. It is limited by the choice of simple materials, to insure broad participation, and by practical limits on staging a tournament, such as the choice of sand and the maximum available load of 15 kg. The take-away here is that those students who really work at this event will have a good understanding of how and why structures do what they do, an understanding that will come through repeated, destructive testing of structures.

There is no significance to holding 15 kg of total load. It is not a design load. Nor is there any significance to holding 10 kg, 5 kg, or 1 kg. Load is load, and what matters is how the structure being tested responds to the load. The 15 kg of load written into this event is a practical limit on what the supervisor is expected to provide. It forces students to build light. Ideally all the structures would be loaded to failure to determine their efficiency and ultimate strength, but no tournament can be expected to provide an open-ended amount of sand. By cutting off the available load, heavy structures with high capacity are self-defeating because they can't utilize their all strength to increase their score. Therefore, students must learn to use minimal resources. Saying that structures must "carry all the load" is a fundamental misunderstanding of the event.

Many years ago, I coached my daughter's Odyssey of the Mind team in a simple tower building problem. She built an 8" tall tower, legs straight up, which weighed 15 grams. The team stacked barbell weights on it, it broke at 960 lbs. We went on to state tournament and got beat by a team carrying 1000 lb. I don't think we need to stage events with massive amounts of weights to load destructively, by allowing structures to score their efficiency at failure with limited maximum load and encouraging team to build light, we accomplish the same thing.

The argument that these structures ought to "carry all the load", because, after all, who wants to be on a structure which collapses - we might be killed - and no good engineer would allow that to happen, is a tired old argument which is not valid in this context. How do you suppose that engineers know how to build safe structures? Maybe it's because someone did the research to learn how structures fail and or they succeed, and how they can best be built with a given set or resources. I think that's what we're doing in this event, we're learning what it takes to make good structures. It's the sort of knowledge that practicing engineers apply to make those real world structures.

In 2004 Towers were required to carry all 15 kg to be in the first tier. At Nationals (in Juniata) the 31st place tower weighed 290 grams and had an efficiency of 52, but it was first tier. The 32nd place tower wieghed 6.46 grams and had an efficiency of 2217. Do you believe that the team that worked harder and learned more was rewarded? Really?

If these structures were actually being judged by the standards of real-world structures, they would be judged with a safety factor of five or more, they would be evaluated for capital cost, serviceablility, longevity, life-cycle costing, aesthetics, and effectiveness at addressing the intended function, whether that is to support traffic, house people, carry power lines, etc. In terms of efficiency, capital cost is likely to be the closest measure, and that depends more on availibility of materials, market conditions, availability of skilled trades to work the materials, suitability of the materials to the climate and specific conditions of the site, and so on. These real world structures would never -that's NEVER - be judged on a measure of load-held vs structure mass.

Structures built for S.O. are not life-preserving structures, and real structures are complex to accurately model or score. These are learning tools, research structures. I am astounded by the amount of information and wisdom shared by the members of this board. I think we've managed to model collaborative research. I wouldn't have it any other way.

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Re: Elevated Bridge B/C

Postby jander14indoor » May 28th, 2010, 6:46 am

Wow, interesting discussion I sparked. Not too surprised. This was at least part of the purpose!

I WAS at the meeting, let me give MY perception of the thought process. Note, the following is the view of only ONE person who was there.

While I agree with Bob that an arbitrary weight is just that, arbitrary for this event, I'm not sure it is only useful for the convenience of the event supervisors.

For the past few years, the ONLY factor students have had to focus on for scoring is 'efficiency' mass held over mass of bridge. This is VERY important for all the reasons Bob said, if you don't know where it breaks, how safe do you know it is?

On the other hand, it is common in engineering to have to build to multiple, often conflicting requirements. Many committee members felt the need to focus some student attention on building to a weight target for the structure events. The usual approach to setting a minimum load to be carried was discussed, but most agreed with Bob's position (as championed by several who were there) that second tiering an otherwise very efficient structure was too harsh a penalty for missing an admittedly arbitrary weight target. And it matters little whether you set the minimum at 1, 5, 10 or 15 kg, you create a discontinuity in the scoring giving results like Bob mentioned where a clearly superior bridge scored below a very poor bridge. On the other hand, if the bridge had been say 0.1 mm too tall you would have had the same result!

The weight held squared over bridge mass was a compromise. It forces the students to at least think about how much load they are carrying as well as the efficiency. It gives some reward to a team that holds close to the maximum as well as designing efficiently. And its a continuous function so similar performing bridges get similar rank.

Now, to see what it does, I like the table balsaman built, and some of the conclusions. But I think you need to look at another table, plotting the old efficiency against mass held. If you do this, you see that for example, an 2000 old efficiency structure that holds 15 kg beats a 2500 old efficiency structure that holds less than 12 kg. A 1000 old eff structure holding the full 15 kilo beats that 2500 old efficiency unless it holds more than 6 kilos. So clearly holding more mass is rewarded without creating discontinuities.

In conclusion, I think all the good things Bob mentions about how structures have been scored while simply adding an addtional factor for the students to consider when preparing for the competition.

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Re: Elevated Bridge B/C

Postby old » May 30th, 2010, 10:33 pm

Personally I have long ago given up trying to figure the rationale for how Science Olympiad events are designed or scored. I don't mean this in a negative way, just that the rules seem to be clearly arbitrary, that's just the way it is. Take the elevated bridge rules for this season. What real world application is there for a point loaded elevated bridge (or any other point loaded bridge)? And what tower has a large point load on the top? What is a "boomilever" anyway? Why would anyone make an elastic powered ball thrower (Trajectory) or a gravity powered thrower of a random sized spherical object (Storm the Castle)? What is the real world equivalent of Battery Buggy or Mousetrap vehicle (or the previous incarnations of Wheeled vehicle and Electric vehicle)? Mission possible is a device specifically designed to be as unreliable as possible (no parallel paths) where a single failure means that the entire device fails, but no engineer in his right mind would purposely design that way. I could go on and on but the point is that I don't see any of these events as having any real world equivalent, just a vague connection.

Each of these events pose interesting engineering problems to solve, and teach the competitors important lessons, why does anyone think that there needs to be anymore rationale than that? I have always felt that the best way to view SO building event rules is that you forget about the title of the event and just follow the rules in a way that give you the best possible score. If you forget that the event is called Elevated Bridge, and just build to the rules, then it is a great event in its one right. On the other hand I do have a problem with events that are designed in a way that unscientifically finds the "winner". Most of the sturcture events are well designed experiments where the winner is nearly always unquestionably the one who built the device that should have recieved the maximum points according to the rules. Some of the other events however are not nearly so well designed. Egg-O Naut, with it's huge dependence on uncontrollable variables (weather) is notorious. Trajectory and Storm the Castle being run outdoors with purposely low density projectiles is another event where uncontolled variables (again weather) greatly effect the outcome. Even when run indoors (with the A/C off, which wasn't the case in Augusta last year) these ballistic trajectory events can greatly reward a competitor for a simply lucky shot. The statistical significance of only one shot counting for the score is so low as to be nearly meaningless from a scientific perspective. This same lack of statistical significance shows up in events like Mousetrap Vehicle, Mystery Architecture, Scrambler, and many other events. Obviously the reason for the lack of statistical significance being incorporated into the design of the event is the practical matter of fitting the event into a reasonable time frame. But it seems to me the Science Olympiad is supposed to be about "science" and proper experimental proceedure, not random chance. If an event cannot be run and judged on proper scientific principles (controlled variables and statisitcally significant outcomes) then it shouldn't be in a science competition, save that for the game shows.

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Re: Elevated Bridge B/C

Postby ichaelm » May 31st, 2010, 7:14 am

On another note, anyone notice these pictures of the 1st place B division bridge?

It's completely different than all the others! Or, at least, it looks that way.

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Re: Elevated Bridge B/C

Postby AlphaTauri » May 31st, 2010, 7:34 am

Wow...I never would have thought of that design. And from the look of it, only possible because of the rule change allowing >1/4" square wood.

It's quite amusing, though- all these delicate bridges built completely of 1/8" square or less placing top 10, and this one, made up what looks like thin sheets of balsa, earning gold.
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Re: Elevated Bridge B/C

Postby Littleboy » May 31st, 2010, 8:10 am

old wrote:Personally I have long ago given up trying to figure the rationale for how Science Olympiad events are designed or scored. I don't mean this in a negative way, just that the rules seem to be clearly arbitrary, that's just the way it is. Take the elevated bridge rules for this season. What real world application is there for a point loaded elevated bridge (or any other point loaded bridge)? And what tower has a large point load on the top? What is a "boomilever" anyway? Why would anyone make an elastic powered ball thrower (Trajectory) or a gravity powered thrower of a random sized spherical object (Storm the Castle)? What is the real world equivalent of Battery Buggy or Mousetrap vehicle (or the previous incarnations of Wheeled vehicle and Electric vehicle)? Mission possible is a device specifically designed to be as unreliable as possible (no parallel paths) where a single failure means that the entire device fails, but no engineer in his right mind would purposely design that way. I could go on and on but the point is that I don't see any of these events as having any real world equivalent, just a vague connection.

Each of these events pose interesting engineering problems to solve, and teach the competitors important lessons, why does anyone think that there needs to be anymore rationale than that? I have always felt that the best way to view SO building event rules is that you forget about the title of the event and just follow the rules in a way that give you the best possible score. If you forget that the event is called Elevated Bridge, and just build to the rules, then it is a great event in its one right. On the other hand I do have a problem with events that are designed in a way that unscientifically finds the "winner". Most of the sturcture events are well designed experiments where the winner is nearly always unquestionably the one who built the device that should have recieved the maximum points according to the rules. Some of the other events however are not nearly so well designed. Egg-O Naut, with it's huge dependence on uncontrollable variables (weather) is notorious. Trajectory and Storm the Castle being run outdoors with purposely low density projectiles is another event where uncontolled variables (again weather) greatly effect the outcome. Even when run indoors (with the A/C off, which wasn't the case in Augusta last year) these ballistic trajectory events can greatly reward a competitor for a simply lucky shot. The statistical significance of only one shot counting for the score is so low as to be nearly meaningless from a scientific perspective. This same lack of statistical significance shows up in events like Mousetrap Vehicle, Mystery Architecture, Scrambler, and many other events. Obviously the reason for the lack of statistical significance being incorporated into the design of the event is the practical matter of fitting the event into a reasonable time frame. But it seems to me the Science Olympiad is supposed to be about "science" and proper experimental proceedure, not random chance. If an event cannot be run and judged on proper scientific principles (controlled variables and statisitcally significant outcomes) then it shouldn't be in a science competition, save that for the game shows.


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ichaelm wrote:On another note, anyone notice these pictures of the 1st place B division bridge?

It's completely different than all the others! Or, at least, it looks that way.

Very unique. How would you even think of doing something like it

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Re: Elevated Bridge B/C

Postby lllazar » May 31st, 2010, 12:03 pm

How do you get sheets that size that weigh less than all these intricate little bridges made of 1/8 squared or less....

Then again the bridge is practically just one side...
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Re: Elevated Bridge B/C

Postby new horizon » May 31st, 2010, 12:07 pm

ichaelm wrote:On another note, anyone notice these pictures of the 1st place B division bridge?

It's completely different than all the others! Or, at least, it looks that way.


I saw that bridge, it look so strange. Does anyone know the construction behind it? Or it's efficiency?

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Re: Elevated Bridge B/C

Postby ichaelm » May 31st, 2010, 12:09 pm

lllazar wrote:How do you get sheets that size that weigh less than all these intricate little bridges made of 1/8 squared or less....

Then again the bridge is practically just one side...

yeah, only 4.50 grams! :o

new horizon wrote:
ichaelm wrote:On another note, anyone notice these pictures of the 1st place B division bridge?

It's completely different than all the others! Or, at least, it looks that way.


I saw that bridge, it look so strange. Does anyone know the construction behind it? Or it's efficiency?


2734 :o

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Re: Elevated Bridge B/C

Postby new horizon » May 31st, 2010, 12:14 pm

did you/your team build that?
if so, props, because that's amazing.

I'm not a bridge person, but where are the bracings? I can't find any... How can something that simple hold so much weight..?

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Re: Elevated Bridge B/C

Postby Littleboy » May 31st, 2010, 12:22 pm

Simple=perfect
If something is simple it usually works better than a weird crazy design

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Re: Elevated Bridge B/C

Postby ichaelm » May 31st, 2010, 12:26 pm

lol no i didnt build it. I just found it on the wiki. Yeah I don't do bridges either :lol: but I find them interesting because I love physics. I have no idea why this is better than all the others though. I guess it's just... strong.

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Re: Elevated Bridge B/C

Postby AlphaTauri » May 31st, 2010, 12:40 pm

Too bad there's no one we can ask...it's from one of the NC teams (Arendell Parrot) and I don't think there are many people on here who are from NC.

If I had to venture a guess as to why this bridge won, I'd say it's because it's so simple. Less pieces = less chance of spontaneous failure. Also, it doesn't look like it'd be easy to tip over either, with the legs slanting outwards, so that's something else this bridge has going for it. I have no idea how they made it so light, though. 4.50 grams...are you sure there wasn't an antigravity field or something canceling out some of its weight? :lol:
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