Thermodynamics B/C

[ic3kreem]

How r u guys studying for this?

is khan academy a good resource? what would be a good follow up after that?

thanks!

[BasuSiddha23]

How r u guys studying for this?

is khan academy a good resource? what would be a good follow up after that?

thanks!

I am using Khan Acamedy and I think its a really good source.http://hyperphysics.phy-astr.gsu.edu/hbase/index.html is good to follow up after that to go more in depth. I really only watch Khan Academy videos on the subject to get a basic understanding.

[retired1]

A quick easy to build effective device. Sized for either B or C div.
For an outer container I used a Breakstone 24 oz cottage cheese plastic container. Beaker was a Pyrex Vista 250 ml.
Next I took a 32 oz styrofoam soft drink cup from a gas station, Dart brand. Mark the cup before cutting and use a very sharp razor blade to cut.
Cut off 1.5 cm of the bottom of the cup.
At the flare, cut 1.5 cm below the center of the flare and 2 cm above.
Cut off about 3 mm of the top of the cup.
Next, I used a very soft styrofoam about 3 mm thick. (It was a protective layer for a new microwave). (Pop paper did not work near as well) Cut a piece 23.5 cm by 7.5 cm to wrap around the beaker. Scotch tape it to the beaker just below the rim. This leaves about 1.5 cm of the bottom of the beaker exposed.
Press the beaker into the flare portion of the foam cup. the bottom of the beaker will be just above the bottom of the cup.
Put 1 layer of the foam in the bottom of the plastic container to insulate that portion.
Cut a hole 1.5 cm in the cover of the plastic container and in the bottom section of the foam cup. You can mark it out with a dime and then cut about 1 mm inside of the marked circle. I used an x-acto knife.

The upper section of the foam cup fits to near the bottom of the plastic container. Insert the covered beaker into the foam cup. Insert the cut off bottom portion of the cup into the beaker and the plastic cover snaps onto the plastic container.
I removed the covered beaker with the foam section still attached, filled it with the measured amount of hot water, immediately inserted the foam cup bottom into the beaker, Immediately placed this into the lined plastic container and immediately placed the plastic cover on and returned to the table. Absolute minimum heat lost this way.
See the next post for a sample result.

[retired1]

~200 ml of 90 C water room temp 23.1 C
insulated / non insulated
1 min 79.2 77.3
5 min 77.3 69.1
10 min 75.3 61.6
15 min 73.2 56.4
20 min 71.4 52.6
25 min 69.1 49.1
30 min 67.3 46.2
This was using a very thin wire thermocouple device.
When removed from the water, the wet fiberglass would cool it down to about 16 C due to evporation
Unstirred, the water temp at the bottom of the beaker was about 2 C less than the center of the solution
With 2 people, the initial temp loss would have been a bit less as an uncovered beaker water looses temp quite rapidly
A metal covered probe gave erratic results.
A non contact thermometer gave lousy results for the insulated container I believe it was reflecting part of the signal back to the instrument.

[arv101]

How are you guys studying for this? What syllabus are you studying based off of?

[kenniky]

How are you guys studying for this? What syllabus are you studying based off of?

So I don't know anything about Thermo but when I was studying for Optics, HyperPhysics was a really good resource.

Here's the starting page for their Thermo stuff (click the images and links to get to more pages): http://hyperphysics.phy-astr.gsu.edu/hbase/heacon.html

I'd expect this site to be super useful

[arv101]

Wow, yes that site is helpful but could someone please give me an event specific syllabus for Thermo because most of these sites give a good foundation of thermodynamics but I want to know what more I need to study. (Be more specific than the rules please )

[rchand]

Can we can insulation material or box around the 15 by 15 by 15 box that the beaker is in?
I saw many videos that did but never specified if you can or not.

[Unome]

Can we can insulation material or box around the 15 by 15 by 15 box that the beaker is in?
I saw many videos that did but never specified if you can or not.

Your question needs a little clarity - it's hard to tell what you're asking.

[arv101]

Can you guys take the following practice test https://drive.google.com/file/d/0By56H9 ... sp=sharing
I did it under 30 minutes, do it with a total of 30 minutes and post your score if you want to along with the ones you got wrong. This can help us rank our selves and then we can discuss the ones we got wrong.

Please don't lie, your username should be pretty anonymous so know one should know, I want accurate results. It's okay the whole point is to learn.