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Re: Keep the Heat B/Thermodynamics C

Posted: February 15th, 2013, 2:37 pm
by soccerkid812
Can you layer glue (non-expandable) along the inside of the box to stop heat from escaping along the corners and sides of the box?

Re: Keep the Heat B/Thermodynamics C

Posted: February 15th, 2013, 4:23 pm
by 135scioly
soccerkid812 wrote:Can you layer glue (non-expandable) along the inside of the box to stop heat from escaping along the corners and sides of the box?
I think that's allowed, but if you'd rather be safe, you can use duct tape. That's what my team did, and it's pretty much like glue.

Re: Keep the Heat B/Thermodynamics C

Posted: February 16th, 2013, 8:23 pm
by siciscio
Um... I have a question about the 2.5 cm rule. I sent an event clarification earlier, and I know that this isn't a place for clarifications, but I wanted your opinions on the subject matter.

I have a portion of my device extend below the lip of the beaker. And it's basically a cylinder that's attached to the under side of the lid. it goes into the beaker like a cap and the lip beaker touches the under side of the lid. The problem is that the tube extends (inside the beaker) lower than the lip of the beaker.

the rule states that "top surface hole must be less than 2.5 cm above the top lip of the beaker". In your opinion would this length include the extension mentioned above?

Thank you :)

Re: Keep the Heat B/Thermodynamics C

Posted: February 16th, 2013, 9:31 pm
by ychen428
I have a very similar device to yours, with something going around and inside my beaker. During our Invitationals, the proctors measured it from the beaker, not the extension, so I would say the extension does not count towards the 2.5cm. It should be within 2.5cm even without the extension.
Beside, it makes sense this way. Otherwise teams would all have extensions to increase the distance from the top hole since most of the heat loss is through the top whole.

Re: Keep the Heat B/Thermodynamics C

Posted: February 17th, 2013, 6:06 pm
by chalker
We've posted a new FAQ about commercial insulation that will hopefully clear some things up: http://soinc.org/node/1112

In addition, there are some other FAQs that might be of interest: http://soinc.org/node/838

Re: Keep the Heat B/Thermodynamics C

Posted: February 18th, 2013, 3:20 pm
by inthewoods
chalker wrote:We've posted a new FAQ about commercial insulation that will hopefully clear some things up: http://soinc.org/node/1112

In addition, there are some other FAQs that might be of interest: http://soinc.org/node/838
FAQ is
02/17/2013 - 21:42 Does the "250mL standard, unaltered empty Pyrex (or similar brand name) beaker" have to be made of glass?
Answer: No.

Doesn't this violate the event rule of a standard 250ml "Pyrex" beaker since the definition of Pyrex is A hard heat-resistant type of glass, typically used for ovenware." Does this mean someone can use a plastic beaker?

Re: Keep the Heat B/Thermodynamics C

Posted: February 18th, 2013, 3:49 pm
by chalker
inthewoods wrote: FAQ is
02/17/2013 - 21:42 Does the "250mL standard, unaltered empty Pyrex (or similar brand name) beaker" have to be made of glass?
Answer: No.

Doesn't this violate the event rule of a standard 250ml "Pyrex" beaker since the definition of Pyrex is A hard heat-resistant type of glass, typically used for ovenware." Does this mean someone can use a plastic beaker?
I think the key words are "or similar brand name". The rules don't say "or similar brand name glass beaker". I don't see any major competitive advantage of using a glass vs. a plastic beaker, and we want this event to be as accessible to everyone as possible, so if you only have plastic beakers available that should be ok.

Re: Keep the Heat B/Thermodynamics C

Posted: February 18th, 2013, 6:33 pm
by awesome90220
135scioly wrote:
ChrisYim wrote:Hey guys. I just wanted to clarify my interpretation of the rules.
We attach an insulator directly on top of the beaker as long as there's a 1.5 cm hole in the center, right?
Yes, you can have an insulator on top but it shouldn't be too thick because keep in mind that your beaker must be 2.5 cm from the top of your insulator, which some people interpret to be the tallest point of your box.

Also, can somebody explain the boundary work equation for constant pressure and temperature?
Could i put a lid on the beaker if there isn't a hole, I know this is in the rules, but I remember seeing someone's device with a full lid

Re: Keep the Heat B/Thermodynamics C

Posted: February 18th, 2013, 8:42 pm
by foreverphysics
awesome90220 wrote:
135scioly wrote:
ChrisYim wrote:Hey guys. I just wanted to clarify my interpretation of the rules.
We attach an insulator directly on top of the beaker as long as there's a 1.5 cm hole in the center, right?
Yes, you can have an insulator on top but it shouldn't be too thick because keep in mind that your beaker must be 2.5 cm from the top of your insulator, which some people interpret to be the tallest point of your box.

Also, can somebody explain the boundary work equation for constant pressure and temperature?
Could i put a lid on the beaker if there isn't a hole, I know this is in the rules, but I remember seeing someone's device with a full lid
You are not allowed to put it directly on the beaker. It must be at least 2.5 cm away from it. If you saw that, then that team was breaking regulations.
That being said, how do you not know the rules yet? Do I need to go over the rules again with you guys before Regs?

Re: Keep the Heat B/Thermodynamics C

Posted: February 18th, 2013, 8:48 pm
by sjwon3789
foreverphysics wrote: You are not allowed to put it directly on the beaker. It must be at least 2.5 cm away from it. If you saw that, then that team was breaking regulations.
That being said, how do you not know the rules yet? Do I need to go over the rules again with you guys before Regs?
Wait, so you can't make a lid with a 1.5 cm diameter hole to cover the beaker? Can't we have a lid as long as the thermometer can access the beaker (plus the 1.5cm diameter rule)?