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At school, we're doing an experiment to try and keep 200mL of cold water in a can cold, while it is put into hot water.

With this in mind:
-can is the standard soda cans you drink out of
-we have to build a little insulated outside covering for the can. (Max 1.75 cm each side)
-We can put things inside the can (e.g. coat it with something)
-There is no top on the can
-everything used is @ room temperature (no putting ice into the can, freezing the can, etc.)
-dimensions cannot be any bigger than 10cm(W) or 20cm(H)

Some materials I've thought to cover the can are:
Cardboard with the little ripples
Styrofoam (sp? lol)
Hair Gel
Aluminum Foil
Coat the inside with wax..


Any suggestions guys? lol

You need to use some type of material that is not thermally conductive.

A whole crapload of AS3

Lol @ the AS3 comment I dont think I'll be able to afford THAT much of AS3


I know I need a material that isn't themally conductive... thats why I came here for suggestions.

"Suspend it in a jar of air." Get jar bigger than the can. Punch hole in the lid. Stick string thru lid and wrap around the top of the can. Hang can so it doesn't touch the sides of the jar tie a knot in the string to hold can up then seal the hole in the lid so water won't leak in. That should keep water cool for at least 30 min.

Good idea, but dont you think having it insulated rather than out in the air would be better?

and also... I forgot to mention that I cannot use already made products such as cups or jars to help in this project... these have to be raw materials..

the air is the insulation...

Also note that the material that you use also must not absorb water, as that would defeat the purpose of the insulation

Find a schematic a thermos on google. Use a design similar. Air is one of the best insulators out there. The lack of air(vacuum) is even better.

Nope........That's what Thermos uses is air. Inner liner surrounded by air inside an outer casing. "Keeps hot thing hot and cold things cold." You probably don't remember the OLD glass thermoses but if you ever dropped one (which I did on a few occasion at lunch period) the glass would break leaving nothing but a casing full of broken glass and whatever fluid was inside. No insulation. Only thing better that air for insulating is the total lack of it (i.e. - perfect vacuum).

Originally posted by binksfan
Nope........That's what Thermos uses is air. Inner liner surrounded by air inside an outer casing. "Keeps hot thing hot and cold things cold." You probably don't remember the OLD glass thermoses but if you ever dropped one (which I did on a few occasion at lunch period) the glass would break leaving nothing but a casing full of broken glass and whatever fluid was inside. No insulation. Only thing better that air for insulating is the total lack of it (i.e. - perfect vacuum).

Who you disagreeing with? Our posts seem awfully similar.

Hey Brembo.....
You win. You posted it while I was typing it. Great minds think alike. Now I suppose my village will be calling wanting me back

KuRe.....
I hate to break this to you but styrofoam, aluminum foil and hair gel sure don't fall into the raw materials catagory either. Neither does the tin can thats gonna be holdin' this cold water. They gotta give you a little leeway here. Suspend the can in another can (bigger one). But it has to be sealed up to prevent warm water leaking in.

Brembo...

I was answering Kure's post just after my original one, where he asked if insulation wouldn't be better than just air.

perhaps I worded it wrong :X what I meant was I cant use materials premade for insulation... such as a styrofoam cup.. Although I'm not too sure on your jar thing, I'll have to ask the teacher on that.

Interesting project. Please let us know the results of the experiment.

(Styrofoam is the only material on your list that would insulate).

vacuum?


sorry, i felt it was expected

Originally posted by Noevo
vacuum?


sorry, i felt it was expected

how to make a vacumn..

put the can in the glass jar. Put a few candles between the jar and the can..

ligh up the candles.... find something to cover the area between the jar and the can..

the flames will eventually die out because it consumed all the air... and u have some sorta vacumn..

it should keep that can cool for a long time...

keep in mind this is a SMALL project for extra credit points Due the 14th.. its a little competition in the class to see who can keep their water coolest. This is what i'm thinking.

Make a 10x10x10 cube out of styrofoam/wood/whatever, then hang the can inside it.

What can I do with the walls of the cube and can to make it repel heat? I heard a light/reflective material, such as aluminum foil, does the job really well.

A vacuum is a nice idea, however please remember that I will need to add the water in the day the experiment. Upon opening the jar, the vacuum will be gone

simple, well i don't know if this would be cheating or not, but you would want to put coat your can with some compound that when it reacts with the waters elements your chemical would create an endothermic (the removal of heat) thus making the surrounding water cooler. The de-ice stuff some ppl use for their driveways makes an exothermic reaction (release of heat) so it melts the ice, just reverse that and you'll keep your can cold by removing any surrounding heat energy. I'll see if I can remember, or write up an equation for some endothermic compund.

I'm sorry if the title is a little misleading, I will only be using the can, no soda. On the day of the experiment I will add cooled water to the can and attempt to keep it cool for 16 minutes with minimal temperature fluctuation.

Originally posted by KuRe
I'm sorry if the title is a little misleading, I will only be using the can, no soda. On the day of the experiment I will add cooled water to the can and attempt to keep it cool for 16 minutes with minimal temperature fluctuation.

How bout the idea I just suggested.... ?

was it illegal?

One of the rules of this experiment was that there was no lid over the can, which kills the vacuum idea. What I dont get is.. why is air the best insulator? If that were true, why would house builders use the fiberglass insulator instead of just making the walls hollow?

The materials I stated in the first post tend to take longer to warm up/ cool down. Using those materials would prevent the heat of the outside water to affect the cool water inside the can.

a koozie, or neoprine(sp x 2 ??) ??

Originally posted by KuRe
One of the rules of this experiment was that there was no lid over the can, which kills the vacuum idea. What I dont get is.. why is air the best insulator? If that were true, why would house builders use the fiberglass insulator instead of just making the walls hollow?

The materials I stated in the first post tend to take longer to warm up/ cool down. Using those materials would prevent the heat of the outside water to affect the cool water inside the can.

there's no lid over the can... there's a lid over the lil space between the jar and the can.. so the flames can die out and use up all the air in there... thus creating some sort of vacumn




get it?

oh Yes, I get it.

Originally posted by KuRe
oh Yes, I get it.

I'm gonna go try it myself.. heh

Air's specific heat is 1060 J/kg
Water's specific heat is 4186 J/kg

So now my question is... why not fill up a jar with water, put the can in the jar, seal up the space between the edge of the jar and the can?

So now the layers would be..

Tub | hot water |Styrofoam cup/jar|room temp water|Can|cold water

Originally posted by KuRe
One of the rules of this experiment was that there was no lid over the can, which kills the vacuum idea. What I dont get is.. why is air the best insulator? If that were true, why would house builders use the fiberglass insulator instead of just making the walls hollow?

The materials I stated in the first post tend to take longer to warm up/ cool down. Using those materials would prevent the heat of the outside water to affect the cool water inside the can.

Ref. your house insulation question..........the walls are porous material, they leak and air passes thru. Would be like punching a hole in your can of cool water and my jar, letting warm water in, they would mix and shortly they would both be the same temperature. The fiberglass insulation just slows down the passage of air so warm air stays inside and cold air stays outside in winter, vice-versa in summer. Look at the constuction of insulated windows. They are just two panes of glass with a layer of air in between. But that air is sealed between the two panes and acts as insulation. Now drill a hole thru both panes of glass and you lose the effect of insulated window. But if you take a wad of fiberglass insulation and stuff it in the holes you just drilled it will help the windows insulation effect because it slows down the transition of cold and warm air.

Originally posted by KuRe
Air's specific heat is 1060 J/kg
Water's specific heat is 4186 J/kg

So now my question is... why not fill up a jar with water, put the can in the jar, seal up the space between the edge of the jar and the can?

So now the layers would be..

Tub | hot water |Styrofoam cup/jar|room temp water|Can|cold water

that'd work.. but where would the fun be without fire?

Originally posted by KuRe
Air's specific heat is 1060 J/kg
Water's specific heat is 4186 J/kg

So now my question is... why not fill up a jar with water, put the can in the jar, seal up the space between the edge of the jar and the can?

So now the layers would be..

Tub | hot water |Styrofoam cup/jar|room temp water|Can|cold water

could you fill up the inner perimeter of the can with ice? but allow the to be hollow enough for the 200 mm water?

no ice everything has to be @ room temperature.

thanks for the explanation of the fiber glass insulation NOW I get why they use it lol.

I've got yet another question.

What would happen If i had salt inside the can.. and then the cold water was added in. Would this keep the water cool longer? or would it cause the water to warm up quicker?

Originally posted by KuRe
no ice everything has to be @ room temperature.

AHA!

I just got a great idea... make the room temperature to 0! wooo...

Immy,

I don't think burning candles will create a vacuum, I think all it'll do is create a lack of oxygen and produce water vapors and carbon dioxide.

You need to make a pump and "draw" a vaccum on the can.

Originally posted by RoundEye
Immy,

I don't think burning candles will create a vacuum, I think all it'll do is create a lack of oxygen and produce water vapors and carbon dioxide.

You need to make a pump and "draw" a vaccum on the can.

ehh.. it does create some sorta vacumn.. I've experimented ... so I have one of them candles... and I cover it tightly when it's still burning... and it sucks the lid in.. and when I try to open it it's hard to open... just personal experiences....

also if u just blow out a candle... it'll create alotta smoke.. and if u light up the smoke... it'll actually make the candle burn again.. kinda funny... well u have to see it to get it..

it grew legs!!!! lol

What would happen If i had salt inside the can.. and then the cold water was added in. Would this keep the water cool longer? or would it cause the water to warm up quicker?

?

Originally posted by KuRe
?

dont think it would affect it at all...if it had ice in it then it would have a reaction, but just water...you get brine

I know salt in water does something to the structure of the water.. I just dont know what.