Keep the Heat B/Thermodynamics C

[haverstall]

Yes, that is one of my questions. Do most competitions have the water transfered from a large hot beaker to the cool 250ml beaker, or is the 250ml beaker already heated?
Also, if you are heating in the water in the 250ml beaker, have you considered evaporation? Some of the water will evaporate by the time it reaches the desired temperature, especially if you are going to 90oC. How do you account for this?

We were lucky in that during the state competition, all the teams had separate Vernier probes, so we took the temp of the water when our time started. Funny thing is that even though they said the water was to be 70 C, it was actually 62.5 C when we measured it. Still to be safe, I would suggest you bring a thermometer yourself, like forever suggested. We did the same, but because of this awesome set up, we didn't have to worry about it.

[Paleofreakazoid]

I'm really sorry if this has been mentioned before, but I was wondering at your state competitions, did they have pre-measured increments of water to pour? Our beaker only measures 25 mL increments, so I was wondering how they would do that at other competitions...

[blazer]

I'm really sorry if this has been mentioned before, but I was wondering at your state competitions, did they have pre-measured increments of water to pour? Our beaker only measures 25 mL increments, so I was wondering how they would do that at other competitions...

At the competitions I've been to, the judges have scooped water out of a large bath, poured it into a graduated cylinder to get the correct volume, and then poured it into my beaker.

[Flavorflav]

As many of these posts attest, the way the judges load the device is the single biggest source of variability in this event. The clarification of 2/21 addresses this problem nicely, by allowing teams to take the internal temperature after loading and before prediction. Unfortunately for us, New York announced at the competition that they did not intend to honor that clarification. Chalkers, do you think that the thermometer could be explicitly allowed in the rules for next year? Predicting exactly how much heat will be lost during a loading procedure that you have limited information about does not seem to me to be the spirit of this event.

[chalker]

As many of these posts attest, the way the judges load the device is the single biggest source of variability in this event. The clarification of 2/21 addresses this problem nicely, by allowing teams to take the internal temperature after loading and before prediction. Unfortunately for us, New York announced at the competition that they did not intend to honor that clarification. Chalkers, do you think that the thermometer could be explicitly allowed in the rules for next year? Predicting exactly how much heat will be lost during a loading procedure that you have limited information about does not seem to me to be the spirit of this event.

It likely will be.

[siciscio]

I don't know if this was mentioned before but what would be a better insulator: one with a low specific heat or a high specic heat? If you were to use a material wouldn't you lose heat more rapidly than one with a higher specific heat. However with a material with a higher specific heat, would it absorb heat from the beaker? so does this I mean I should use materials with high specific heat or low specific heat? Thanks

[harryk]

I don't know if this was mentioned before but what would be a better insulator: one with a low specific heat or a high specic heat? If you were to use a material wouldn't you lose heat more rapidly than one with a higher specific heat. However with a material with a higher specific heat, would it absorb heat from the beaker? so does this I mean I should use materials with high specific heat or low specific heat? Thanks

Specific heat doesn't neccesarily correspond to insulative property, though you defintely want to avoid using materials with a high specific heat because they would absorb the heat from the beaker. Though a material with low specific heat isn't always a good insulator. What you want to know is the thermal conductivity of the material, here is a list on conductivities: http://en.wikipedia.org/wiki/List_of_th ... uctivities

[siciscio]

I don't know if this was mentioned before but what would be a better insulator: one with a low specific heat or a high specic heat? If you were to use a material wouldn't you lose heat more rapidly than one with a higher specific heat. However with a material with a higher specific heat, would it absorb heat from the beaker? so does this I mean I should use materials with high specific heat or low specific heat? Thanks

Specific heat doesn't neccesarily correspond to insulative property, though you defintely want to avoid using materials with a high specific heat because they would absorb the heat from the beaker. Though a material with low specific heat isn't always a good insulator. What you want to know is the thermal conductivity of the material, here is a list on conductivities: http://en.wikipedia.org/wiki/List_of_th ... uctivities

Ok. Thanks

[JustDroobles]

For state, with so many different levels of volume, temperature, and time, how did you test your device to collect data for accurate predictions? We have changed our device since regionals and have state on April 28th, and I am having difficulty coming up with a system to test my device to the precision I would need at state within only three weeks. What efficient systems have you developed for testing your devices?

[Scipuppy]

For state, with so many different levels of volume, temperature, and time, how did you test your device to collect data for accurate predictions? We have changed our device since regionals and have state on April 28th, and I am having difficulty coming up with a system to test my device to the precision I would need at state within only three weeks. What efficient systems have you developed for testing your devices?

We had a similar problem, we didn't finish until just before states, we ended up needing to bring the device home a lot. We did our calibrations for every 5 or 10 degrees, and every 10 mL. However, this takes a LOT of extra work. I would advise using a calculator that can connect to a probe, especially one that can record data so you don't need to do it by hand. This makes it a lot easier. I would start with just every 10 degrees and 10ml increments.