Keep the Heat B/Thermodynamics C

[chalker]

Chalker,
Can you comment further on the allowance of Al foil tape to fasten edges? Seems this material is only a combination of allowed Al foil & tape. Thanks,

As I've emphasized time and again, this is not the place for official clarifications. Foil tape seems to be a bit of a gray area that there might be some disagreement over amongst the committee members, so I"m not going to give an unofficial response here.

[Primate]

Benchmark from NY Midwestern Regionals:

• Starting Temperature: 74 ± 10 ºC *see below
  Room Temperature: 23ºC
  Volume: 100mL
  Time: 30 mins
  
  Temperature at t=1: 71ºC
  Temperature at t=30: 55.5ºC
  Predicted Temperature: 54.6ºC

Note: They didn't quite follow the rules. Rather than providing a source bath of water at a fixed temperature, they carried around a jug of hot water and stuck a probe in once we had the beaker loaded to give us an exact reading. So we all started at different temperatures, and received our reading at anywhere from t=45s to t=90s. So that "starting temperature" isn't useful. Given that our device kept 100mL water at 71ºC after one minute, I'd say the source water bath (the real "starting temperature") was 78ºC.

How's that stack up to everyone else?

[Schrodingerscat]

Benchmark from NY Midwestern Regionals:

• Starting Temperature: 74 ± 10 ºC *see below
  Room Temperature: 23ºC
  Volume: 100mL
  Time: 30 mins
  
  Temperature at t=1: 71ºC
  Temperature at t=30: 55.5ºC
  Predicted Temperature: 54.6ºC

Note: They didn't quite follow the rules. Rather than providing a source bath of water at a fixed temperature, they carried around a jug of hot water and stuck a probe in once we had the beaker loaded to give us an exact reading. So we all started at different temperatures, and received our reading at anywhere from t=45s to t=90s. So that "starting temperature" isn't useful. Given that our device kept 100mL water at 71ºC after one minute, I'd say the source water bath (the real "starting temperature") was 78ºC.

How's that stack up to everyone else?

With our old thermo device (don't have the graphs for our new device, probably a little better) I would predict about 54 degrees as well from my graphs.

[Primate]

Benchmark from NY Midwestern Regionals:

• Starting Temperature: 74 ± 10 ºC *see below
  Room Temperature: 23ºC
  Volume: 100mL
  Time: 30 mins
  
  Temperature at t=1: 71ºC
  Temperature at t=30: 55.5ºC
  Predicted Temperature: 54.6ºC

Note: They didn't quite follow the rules. Rather than providing a source bath of water at a fixed temperature, they carried around a jug of hot water and stuck a probe in once we had the beaker loaded to give us an exact reading. So we all started at different temperatures, and received our reading at anywhere from t=45s to t=90s. So that "starting temperature" isn't useful. Given that our device kept 100mL water at 71ºC after one minute, I'd say the source water bath (the real "starting temperature") was 78ºC.

How's that stack up to everyone else?

With our old thermo device (don't have the graphs for our new device, probably a little better) I would predict about 54 degrees as well from my graphs.

Yeah, that seemed to be the average heat retention for the top five. I know the third place team kept only .5ºC less heat, so I imagine it came down to the tests and predictions for the top five.

[Schrodingerscat]

It does appear that there might be a limit for the construction parameters (at least for the common methods under them) that most of the good devices are approaching, particularly looking at how little with what ought to be significant improvements in the device actually yielded.

[Primate]

It does appear that there might be a limit for the construction parameters (at least for the common methods under them) that most of the good devices are approaching, particularly looking at how little with what ought to be significant improvements in the device actually yielded.

Yep, we have to bring the beaker into thermodynamic equilibrium, which accounts for a great deal of the lost heat.

[Flavorflav]

Honestly, I think that the enormous hole that everybody has to have in their lid nearly eliminates the gap between a good device and a great one. Perhaps next year we could remove lids for testing, or allow the hole to self-seal around the probe?

[Wil4+1]

Al tape should be allowed by the rule. Virtually Al foil plus glue is aluminum tape. Foil is allowed and glue is used for fastening.

[chalker]

Al tape should be allowed by the rule. Virtually Al foil plus glue is aluminum tape. Foil is allowed and glue is used for fastening.

The concern in my mind is whether or not you can use Al tape for things OTHER THAN fastening... which I think some people are asking about.

[Wil4+1]

Chaker wrote:
The concern in my mind is whether or not you can use Al tape for things OTHER THAN fastening... which I think some people are asking about.

The Al tape should not be classified as the "tape" as defined by the rule. The Al tape should be classified as Al foils (insulation material allowed). The adhesive on the back is the glue that fastens to the foil to other rigid structure. If everybody think this way, there are no rules violated.