Thermodynamics B/C

[arv101]

Also, how are you guys testing your devices? More specifically how are you heating up the water to exact degrees and keeping it their?

[soyuppy]

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.

can we assume the use of pre-fab container is allow? Although it's not clearly state, but I though we have to build/construct the container as well. So by building device, it's simply mean finding the right material to insulate using a pre-fab container as long that container fit within the cube specification?

[chalker]

can we assume the use of pre-fab container is allow? Although it's not clearly state, but I though we have to build/construct the container as well. So by building device, it's simply mean finding the right material to insulate using a pre-fab container as long that container fit within the cube specification?

Keep in mind the SO has an official building policy (https://www.soinc.org/building-and-tools-policy). It's going to be up to the individual event supervisor to determine whether you 'constructed' a pre-fab container.

[retired1]

Paragraph 1 of the rules states that the teams must construct an insulating device.
The suggested device is in no way prefabricated. It uses available materials to "construct" the device.
The referenced SO policy has nothing in it that I perceive as forbidding the use of available containers that were not intended to be a device for this competition.
If anybody is worried about it, cut 0.1 mm out of the plastic container and tape it back together.
For the replacement bottom Cut a hole (that just fits the modified plastic material) in a 14 cm square piece of builders foam insulation board and glue that piece to another section of foam. Some big box stores will give you a piece from a damaged piece or sell it to you at a serious mark down. We have enough construction of houses here that I can get "drops" from the building contractor. Dumpster diving is also an option, but not a great one.
Another option would be to build a cardboard box, Set the modified plastic container in the box and fill around it with spray insulation foam from a big box store.
For the true purist, cut open the plastic container and use it as a template to cut some heavy card stock or similar and make your own container.
The heart of the proposed device is using sections of a 32 oz drink cup which has to be legal. The outer portion will be up to each teams ingenuity and material availability.

[Alex-RCHS]

Are you guys worried at all about the time between putting the hot water in the beaker and putting the beaker in the device? I’m worried that the cooling in that time period will have so significant an effect that prediction will be close to random. (In fairness, I haven’t tested myself yet so I could be blowing this out of proportion. I’m just curious what you all think.)

[BasuSiddha23]

I hope this is okay to ask,

This is my first year of doing thermodynamics and I am just starting to experiment with different devices. What are some of the ending temperatures/scores anyone got from their device after 30 minutes? So far, the variables I've tested with so far are using 150 ml, starting at 90 C, no ice water, and for 30 minutes. I just want to see where I am and around where everyone has got, or maybe really good scores

By the way, my highest temperature is 63.3 degrees C

[kendreaditya]

I hope this is okay to ask,

This is my first year of doing thermodynamics and I am just starting to experiment with different devices. What are some of the ending temperatures/scores anyone got from their device after 30 minutes? So far, the variables I've tested with so far are using 150 ml, starting at 90 C, no ice water, and for 30 minutes. I just want to see where I am and around where everyone has got, or maybe really good scores

By the way, my highest temperature is 63.3 degrees C

Why wouldn't it be a valid question?

This is also my first year doing thermodynamics. I am also getting similar results, in 40 mins I got 63.3 C. I am using aerogel along with aluminum foil to keep radiation from leaking. This may seem counter-intuitive by if you think about it, aerogel just keeps the conduction low, however aluminum conduction it, but since its a thin layer the conduction does not make a big difference, but the aluminum keeps the beaker warm form the conduction, this makes it so the aluminum is like a heat reservoir. I am pretty sure this is my thermal vacuum flasks are steal.

Also, I was thinking to put Argon gas in the beaker to keep convection from happening.

Good Luck BasuSiddha23! Hope you do well!

[arv101]

How are you guys studying for the written test portion?

[kendreaditya]

Does anyone else have scores and temperatures they can share? What insulation are you using?

I am using Aerogel to keep conduction rates down, aluminum foil to keep radiation waves inside, and a whole cover over the device to keep the air from coming inside, this helps with convection.

[WhatScience?]

Does anyone else have scores and temperatures they can share? What insulation are you using?

I am using Aerogel to keep conduction rates down, aluminum foil to keep radiation waves inside, and a whole cover over the device to keep the air from coming inside, this helps with convection.

Where are you buying your aerogel from?