Fat/Oil Insulation - 2

[knlk]

Okay, I haven't started my project and I don't know where to start. I wanted to do one on fat insulators. I thought about doing different kinds
of animal fats - lard, beef fat, lamb fat, chicken fat- and test the ability to insulate for each one. I talked to my sister about it, and she was like, 'so what?' 'what's the purpose?' I, too, realized that this experiment wouldn't have any meaningful conclusion...unless I do something different. For the method part, I was going to put aluminum cans (with hot/warm water inside) wrapped around a bag(the fats inside) in an ice bath and see how long the warm water keeps its temperature. I know it's too easy/simple for a high school project, but I have very little time. However, the big big problem is: ① I don't have a hypothesis (i have no supporting info to guess which one will insulate the best) ②. Even if the experiment goes well, there is no really a meaningful result( it doesn't test the 'so what?' test). I will really appreciate your help... I'm very lost and this is making me anxious these days. *I have about 9 full days (vacation) for the experiment as well as couple school days.
Could you make any suggestion? - saturated v. unsaturated // fat content- high,low // i'm making these stuff up...

[deleted-2574]

Hi knlk,

A related question came up recently on sciencebuddies.

Please consult:
https://www.sciencebuddies.org/science- ... =26&t=4321
Please also excuse if you were aware of this page.
Thanks.

This may not be exactly what you were looking for. Hopefully, it will help.

[deleted-71487]

This sounds like an interesting project.

I don't think it needs to have a "purpose" to be useful. Simply finding out which fat is most insulating is an interesting question by itself. Even if you find that all the fats have the same insulating properties, it's still a good experiment. I think this is fairly likely, because most animal fats are very similar. This would make a reasonable hypothesis to test. You could also compare animal and vegetable fats (and perhaps manufactured fats containing trans-fatty acid, if you can find any margarine or shortening that still uses them).

Your experimental procedure might need some work. I would suggest thinking about all the places where the can might lose heat, and figure out how you are going to keep the insulating layer of fat a constant thickness, etc. One thought that comes to mind: You might want to consider nesting 2 different containers, such as perhaps filling a measuring cup with fat and pushing the can into it to squeeze out the excess... if you mark the height on the can right, you can get a nice even layer. A plastic bag wrapped around might be hard to control. Or you could simply put the thermometer directly into the fat and see how long it takes for the cold to reach the center.

You'll want to carefully control the independent variables such as starting temperature of the 2 baths, temperature of the fat, thickness, etc., and measure the temperature change as accurately as possible (the differences might be small). You'll also probably want to repeat the measurements several times and collect your data.

I haven't found any easily discoverable online information regarding the insulating properties of different animal fats to use as references. That is interesting, because it might mean this is something that is not heavily studied. But it does mean that your sources may only be peripherally related to your question.

Darn, I wrote all of this just before David posted his response. Yes, that other posting is very interesting and relevant.

[deleted-71588]

Thermodynamics and heat transfer is an area of science and engineering that is important to a lot of other scientific areas that involve medicine, biology, architecture, manufacturing processes, aerodynamics, energy, environmental conservation, and a whole lot more. It isn't an easy area to experiment in because of the difficulty in coming up with ways to control all of the factors required to make a fair test; however, it doesn't take any sophisticated or complicated equipment or specialized knowledge. This is an area where you do have to understand multiple heat transfer mechanisms and do some thinking ahead of time so that you can get some meaninful results other than I don't have a fair comparison.

The thread
https://www.sciencebuddies.org/science- ... =26&t=4321 demonstrates how easy it is to do an experiment without sufficient understanding and get results from which you can't make any useful conclusions.

It is good that you are starting to think about whether your initial project ideas are good ones. I recommend doing some reading on "heat transfer" via "radiation", "convection", and "conduction" so you have a basis for understanding the multiple thermal transfer mechanisms.

[knlk]

Thank you experts! Your comments give me hope
Do you think I can get those fats at a local grocery? now that's the question.. I know I can get lard easily, but other fats..? hmm

[MelissaB]

You may or may not be able to get them at a local grocery, but the local grocery should be able to tell you which butcher supplies them, and you should be able to get them at that butcher's .

[knlk]

Hi,
I still have some questions.
So I tested lard, beef fat (suet), crisco (vegetable shortening), and control (no fat). My result was: control-crisco-lard-beef fat (the control being the least efficient at insulating). I think it is a fair result, and I realized the order was consistent with the increasing amount of saturated fats. (Beef fat has much higher saturated fat content than others, and lard has more than crisco). I know saturated fats are alkanes - containing only single bonds. And unsaturated fats have multiple bonds(I don't know if it's just double or more). My sister said that single bonds make things tighter and double bonds- looser. I could not find any reliable resources on this topic and I have very little organic chemistry knowledge. What would be the connection between the chemical properties(molecular descriptions) of (un)saturated fats and the ability to insulate?
Also, I saw the other post "Lipid Insulators (https://www.sciencebuddies.org/science- ... 21&start=0) " which was also helpful. He/she said, "if the valence molecular level is full, then insulation occurs. The valence level is full for the saturated lard.." I didn't know valence level and insulation was related... could you explain the relationship please?

To sum up..
I would like to know the connection between the bonds(single/double) and the insulating abilities
and about the valence molecular level being full. If you could also recommend any readings on insualtion or anything related to this, it'd be awesom!!!
Thank you

[deleted-71447]

Hi knlk,
I merged your new topic with your old topic. Please keep posts related to this project in this thread using the "Post Reply" button so that the experts can follow the progress of your project.
Thanks,
Chris

[deleted-2574]

Hi knlk,

There are two types of insulation. One is electrical insulation; the other is heat insulation.

The two are related; please see http://wiki.answers.com/Q/Why_does_heat ... &src=ansTT
for an explanation.

Basically, the free electrons that conduct electricity also transfer heat.

[deleted-71712]

Hi knlk,

Congrats on obtaining your data.

About valence orbitals: This concept is really more relevant to electrical conduction. In good conductors of electricity, such as metals, electrons can jump between openings in the highest energy levels of different atoms; since they can move easily through the material, they carry the majority of heat as well, and electrical and thermal conductivity are fairly well correlated.

http://en.wikipedia.org/wiki/Valence_electron
http://en.wikipedia.org/wiki/Thermal_co ... y#Examples

However, you are not dealing with metals. Lipids' valence orbitals should be nearly completely full, meaning that electrons would have to jump into an energy level higher than the valence level to move from one molecule to another -- and this would require a lot of energy. So, valence orbitals are interesting to read about, but I don't expect that that's where you'll find the best explanation for your observations.

Now, about single and double bonds between carbon atoms. Single bonds allow much more rotation at the site of the bond and thus flexibility along a chain, while double bonds are less flexible. So, in the sense of ability to rotate, I would describe double bonds as "tighter". However, molecules that are more flexible are able to pack together more tightly, resulting in a denser material (all other things being equal... but polar interactions are some of the most important of those "other things", and those shouldn't be important in your materials). You can easily measure the density of your materials -- just measure the mass of a given volume (at the temperature you did your experiment, and watch out for air bubbles) and calculate the density. To understand why density is relevant, think/read about why vacuum is a good thermal insulator, and why gases are usually better than solids or liquids.

A few sources that mention single and double bond flexibilities:

http://books.google.com/books?id=Bxd8Fl ... &ct=result
http://www.pua.edu.eg/PUASite/uploads/f ... re%205.pdf (bottom of page 4 -- but be careful. This does NOT mean that your unsaturated lipids are long, straight molecules -- the fact that all the chains are anchored at one end contributes greatly to the structure shown.)
http://books.google.com/books?id=sLSdqx ... &ct=result
http://www.chem.uic.edu/web1/OCOL-II/WIN/ALKANE/F3.HTM

In addition to seeing whether density correlates with your measurements, I would encourage you to read about thermal conductivity and think about how heat is transferred and how this could be related to the prevalence of single and double bonds and their relative flexibilities.

Amanda

[deleted-2574]

Hi knlk,

Another resource is:
http://www.usc.edu/CSSF/History/2003/Projects/S1519.pdf

This page is a synopsis of a science fair project that measured the insulating properties of different fats. Insulation from both hot and cold temperatures are measured.

You might see if there are any useful ideas here. You could also form a hypothesis of how the hot temperature insulation compares to the cold temperature insulation.