Keep the Heat B/Thermodynamics C

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smartkid222
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Re: Keep the Heat B/Thermodynamics C

Post by smartkid222 » January 14th, 2012, 5:05 pm

I was looking through the image gallery and noticed that there was not a section for Thermodyanmics. Perhaps it would be a good idea to have a section in case anyone wanted to post a picture of their device?
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Re: Keep the Heat B/Thermodynamics C

Post by JimY » January 15th, 2012, 9:20 am

As our team has been testing its thermodynamics devices as well as the outside beaker, it's becoming apparent that the choices the event coordinator makes with regard to temperature, volume of hot water, and time can have a relatively large influence on the weighting between Parts 1 and 2 of the event. For example, low volumes + high temps + long times = the highest part 1 heat retention scores for our devices. The opposite of the three variables makes the lowest heat retention scores, by more than a factor of 3! So, it will be interesting if event coordinators know this, and which part of the event they choose to stress more on competition day.

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Re: Keep the Heat B/Thermodynamics C

Post by blue cobra » January 15th, 2012, 1:53 pm

Which independent, intensive properties completely satisfy the state of a pure, compressible system?
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Re: Keep the Heat B/Thermodynamics C

Post by gorf250 » January 16th, 2012, 8:49 am

So I have a question that is similar to the one about the ink on the cardboard. The box I built has various pencil markings on the wood that I wrote when cutting it, and I was planning on labeling the box with our team's name and number. Would this be considered illegal since graphite is not in the list of allowed materials? I'm thinking about submitting an official clarification.
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Re: Keep the Heat B/Thermodynamics C

Post by NinjaChicken » January 16th, 2012, 8:59 am

gorf250 wrote:So I have a question that is similar to the one about the ink on the cardboard. The box I built has various pencil markings on the wood that I wrote when cutting it, and I was planning on labeling the box with our team's name and number. Would this be considered illegal since graphite is not in the list of allowed materials? I'm thinking about submitting an official clarification.
Haha I'm sure a few pencil markings aren't adding a huge amount of insulation to your device, I'm sure it's fine.
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Re: Keep the Heat B/Thermodynamics C

Post by Adiguy17 » January 17th, 2012, 1:28 pm

Has anyone tested their device at either a competition or just for practice? If so, can you tell me the results because I want to know how well I am doing compared to others. My current result is 18 degrees difference. Thank you in advance.

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Re: Keep the Heat B/Thermodynamics C

Post by OldSpice » January 17th, 2012, 2:32 pm

Adiguy17 wrote:Has anyone tested their device at either a competition or just for practice? If so, can you tell me the results because I want to know how well I am doing compared to others. My current result is 18 degrees difference. Thank you in advance.
It really depends on your starting volume as well as your starting temperature. My schools b-team claimed to have beaten my device in testing with only a 5 degree loss, but what they failed to inform me was that they had tested it with the 250 mL beaker completely filled and the starting temperature was ridiculously low. There can be pretty huge variances in your temperature loss depending on those factors.
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Re: Keep the Heat B/Thermodynamics C

Post by coach99 » January 17th, 2012, 5:24 pm

chalker wrote:
koolaid147 wrote:Hi all,
I am doing Keep the Heat and I read the clarifications/FAQ and read about cork, but I still had a question. I have some leftover cork flooring I found and it is comprised of a layer of just pressed cork granules, wood and then another layer of pressed cork granules. I'm sure they are granules because you can peel them off with a fingernail. Would this be Legal? Also could I use a wine cork to close the probe hole on the top? Last question, is spray painting allowed on the outside of the box?

First, standard disclaimer about this not being the place for official clarifications.. you should submit one to soinc.org if you want such an answer. That said, note there is a distinct difference between a granular material and a material that is comprised of granules. The official FAQ you mentioned talks about DISCRETE macroscopic particles that interact. If there particles have somehow been modified such that they aren't discrete anymore or interact, then I think most people would agree the material is not granular.

Regarding the spray painting, why risk having a event supervisor DQ you for something that isn't explicitly on the 'allowed materials' list?
I guess that glued composite materials would also be ruled out by the last sentence of 3a which prohibits fastening materials which contribute to insulating properties.

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Re: Keep the Heat B/Thermodynamics C

Post by JimY » January 17th, 2012, 5:46 pm

There are two main problems with posting results here and asking others for a comparison:
1. If you don't post the room temp, the hot water temp, the total elapsed time, the hot water volume, AND the ice water volume, nobody can legitimately compare one device with another. So wise up everyone! If you want a comparison, these 5 items are required.
2. What makes anyone think that someone else has done the same experiment (all 5 conditions match)? However, once enough experiments have been done, the results can be correlated such that you can predict what will happen for any starting combined hot plus ice water temp, any elapsed time between 20 and 40 minutes, any room temp, and any water volume between 50 ml and the max volume of the beaker (= can include up to 100 ml ice water plus 150 ml hot water) even if you haven't done an experiment that is close to the conditions listed. The questions then are how many experiments are needed to create a good correlation, which experiments should be performed, and how do you actually perform a multi-variable correlation such that you have a high degree of confidence in the results and can thus predict what your device will do under any set of applicable conditions with good accuracy (within about 0.5 C). Assuming that you can figure all of these things out, then you can compare your device to any other, as long as the 5 items above are all given.

No wonder nobody has responded to requests for comparisons between devices.

I see the difficulty in coming up with that ultimate correlation where you can predict anything for your device with a high degree of accuracy. Whether or not you know what I'm talking about, get someone to help you. You need both design of experiments advice as well as correlation help. A good statistician may work. A math teacher might also work. A third alternative is an engineer. Someone that understands the physics of the situation might not hurt either. If you don't get design of experiments advice, you will run out of time before you do all the experiments that you think you need to do. If you don't get correlation help, you are likely to head the wrong way and end up needing several smaller correlations rather than a single larger one to cover all the possible independent variable ranges.

I'm wondering whether or not the event rule writers realized what they were getting us into, especially for B division.

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Re: Keep the Heat B/Thermodynamics C

Post by OldSpice » January 17th, 2012, 6:16 pm

JimY wrote: I see the difficulty in coming up with that ultimate correlation where you can predict anything for your device with a high degree of accuracy.

...

I'm wondering whether or not the event rule writers realized what they were getting us into, especially for B division.
I agree with you to a degree here. (lol temperature pun) No but in all seriousness I built and refined my teams device and it took me about 6 ours give or take.
My partner then ran upwards of a hundred tests over the course of two months. That's only 3 tests per day and all you really have to do is set up the device and stick the temperature probe in there and press record. To be honest I think this event requires less effort than a lot of events.
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