Keep the Heat B/Thermodynamics C

[TheLeftEye]

Sorry for the double post, but I have a question about the "Keep the Heat Invitationals Test" on the test exchange, the second one down.

14) Given the specific heat capacity of ice is 2100 Jkg-1oC-1, and the specific heat capacity of water is 4200 Jkg-1oC-1. For the same mass of ice and water, if the same amount of heat is added to the ice and water:
a) The temperature of the Ice will increase 2 times the temperature increase of the water
b) The temperature of the Ice and water will increase the same amount.
c) The temperature of the Ice will increase 0.5 times the temperature increase of the water
d) Not enough information is provided determine the relative temperature change

The key says that the answer is a), but couldn't you argue that it could be d) since the temperature of one or both could stay the same if the amount of heat added doesn't surpass the latent heat of fusion/vaporization of water and if both the ice and the water are going through a phase change?

You could, but the problem is, if they don't state it in the question it s most likely not the case. Thats the problem with Keep The Heat: you can never be certain of the question.

[foreverphysics]

I have to say, this event was incredibly well-run at Nats. Very nice. They were really precise with their water measurements, it was fast, and timing was very accurate. We screwed up, but that was our fault, not theirs.

The only I didn't like was that they made us impound our calculators--which left me with no calculator for Optics.

[TheLeftEye]

I liked the event as well, but I never knew that we would need to know about electricity

[Schrodingerscat]

I liked the event as well, but I never knew that we would need to know about electricity

What kind of questions about electricity did they ask? Like power type questions (eg I have seen a few in thermo textbooks about something being heated with a resistor or a lightbulb remaining on in a refridgerator)?

[RAntonello]

I was wondering how other insulation devices did at nats. What were the best final temps and the most innovative ideas?

[The Architect]

I was wondering how other insulation devices did at nats. What were the best final temps and the most innovative ideas?

Unfortunately, my partner and I were never told any of the final data, but I am not sure about other teams. Every device that I saw, except for mine, looked the same. A giant cube made out of wood with whatever insulates inside of it. Our device was kind of the opposite of that, a small (16 cm. height and diameter) cardboard cylinder that had worked very well in the past. If the retention score was what we thought that it was going to be, then we would have gotten 26 points on the retention.

[Paleofreakazoid]

I wish they would have given us our final temps...when we asked if they would give us our final temperatures, they said no...and smiled! I suppose there isn't much we can do now though...Out of curiosity, what were other team's predicted temperatures? And, if you care to share, how much do your predictions typically deviate from the actual temperature?

[foreverphysics]

I wish they would have given us our final temps...when we asked if they would give us our final temperatures, they said no...and smiled! I suppose there isn't much we can do now though...Out of curiosity, what were other team's predicted temperatures? And, if you care to share, how much do your predictions typically deviate from the actual temperature?

I know that our final temp was within the range of 56-57 degrees. (We had a temperature probe.) Typically we're anywhere from 0.2-0.6 degrees off. (Temperature probe measures to nearest tenth of a degree.)

I was wondering how other insulation devices did at nats. What were the best final temps and the most innovative ideas?

Unfortunately, my partner and I were never told any of the final data, but I am not sure about other teams. Every device that I saw, except for mine, looked the same. A giant cube made out of wood with whatever insulates inside of it. Our device was kind of the opposite of that, a small (16 cm. height and diameter) cardboard cylinder that had worked very well in the past. If the retention score was what we thought that it was going to be, then we would have gotten 26 points on the retention.

That's what our machine was. Not a cube, but a cardboard cylinder. Actually, my prediction was ~10 degrees off because we rebuilt our entire device from about 7:00 in the morning to 7:30--literally right before we got in line for impound. And we didn't have superglue either, so we begged two drops from some team or other. So my graphs didn't work for our new device. Also, the beaker got stuck in the device right before insulation, and I took it out and left it in the air...which meant that the starting temp was 61 degrees as opposed to the 72 degrees it was supposed to be. Yeah...no graphs, untested device, bad starting point...

We got tenth. I honestly think that if our device hadn't broken the night before, we would have medaled. I also would have rebuilt our device the night before competition, but my partner was being all ehhhhh and forced me to sleep. I was honestly very surprised when I got tenth, but also hugely disappointed, because I know that had our device not screwed up so badly, we would have done much better.

[siciscio]

Any thoughts on how next years rules would be different from this years?

[space scientist]

Any thoughts on how next years rules would be different from this years?

Personally, I hope that the rules for next year will define exactly what the topics for the test will be (in a similar manner to how it is done in the Optics rules), but that might take up too much space. I'm not too concerned about the issue with temperature loss due to the heat capacity of the beakers since you can approximate that to about 10 degrees Celsius (at least for Division B), but it would be nice to to get a more exact temperature to use for calculating the final beaker temperature. Other than that, there isn't really anything in the rules that I think needs to be changed.