Oh my, handy the scientist here.
Yoohoo!!! You guys ever think to get a plastic cup & an aluminum one with a thermometer in each one, then pour in some cold liquid. Wait & watch the temperature.
Oh my how easy it is.
My vote is the plastic keeps it cooler longer because an aluminum can is colder to the touch, which means the heat is taken from it quicker.
Ummm, because plastic is cheap, and cheap to form into lots of neat shapes?
If you remember old thermoses, they were (are?) made with two layers of glass, with a vacuum in between to cut down on conductive heat transfer. That glass was often aluminized, to cut down on radiative heat transfer.
Cheater! :o
As far as he aluminum can feeling colder, the conductive heat transfer into your finger is more efficient than into air.
I’m not saying that aluminum is better, just that unless you know the relative importance of conductive and radiative heat transfer, you don’t know.
I’ll also point out that the importance of conductive heat transfer depends on the surface the can is sitting on. Either one will get warm faster on an aluminum counter than on a styrofoam block.
It is too clear, and so it is hard to see.
I got a couple of old metal coolers still,one is insulated with spun glass,it’s so old. plastic pretty much replaced metal cause of cost. Don’t go gettin PET confused with foamed plastics now. What some of you have been so kind to refer to as my brain is telling me that the plastic will keep liquid colder ,even with all the factors figured in,but the diff is gonna be so small that for all practical perposes it is moot.Course the whole purpose of this board is mooting,so I sent another Email to those engineers that I got involved with the thick can thin can deal. Stand by. Took about two days to get an answer last time. .
“Pardon me while I have a strange interlude.”-Marx
Must have missed this one. Got a link?
It is too clear, and so it is hard to see.
http://www.straightdope.com/ubb/Forum3/HTML/001959.html
http://www.straightdope.com/ubb/Forum3/HTML/002101.html
They both suck compared to styrofoam.
I have a big plastic cup that’s insulated with styrofoam. My drinks still have ice floating in them 8 hours after the drink was poured. (it’s a 52oz cup, so yes, the beverage sometimes does last 8 hours)
puffington
Sytrofoam is a plastic made by Dow Chemical Company, and the type your refering to has the air trapped in it. Polystyrene the actual common name, can and is molded without the air cells too.
BBaker
Do you have a facility to make the molds and run the product?
Contact the material manufacturers for help if you do.
Do you need to produce the product or molds outside of your firm?
Get hold of a firm that molds palstic or alluminium and they can help you. They work with these materials all the time, and will work with your design department. They will of coarse expect to make the molds or mold the product that they helped you with.
Actually, my company has nothing to do with this. This started out as a completely frivolous debate about whether your drink stays colder in a can or a plastic bottle, and subsequently mushroomed into a controversy with major personal ramifications, including bragging rights and severe public humiliation.
Brian, “The Enchanter”
well, this thread has fizzled out, and I never got a good answer… so I thought I would add another post to bring it back to the forefront… sorry 
Brian, “The Enchanter”
That’s because it’s a more complicated question than you realized, without a single answer correct for all cases. You have two competing processes. Without specifying the conditions better, there is no good answer.
Perhaps you should buy a couple thermometers, take Handy’s advice, and let us know how it turns out.
It is too clear, and so it is hard to see.
Actually, I knew that it was an extremely complex issue, thus, the reason I brought it up here. The conditions are simple. If you have a cold beverage stored in an aluminum can and another stored (at the same temperature) in a plastice (PET) bottle, and you open each and expose them to, say, a 70 degree room, which will warm up faster?.. maybe another experiment should be performed outside in the sun as well, considering some of the theories…
At any rate, the practical details of conducting this experiment are what I’m having trouble with… I have yet to find a source for very accurate, inexpensive thermometers that will “go down” to the necessary temperatures and have a high level of consistency. (From my photography days, I know that most thermometers will not give exactly the same reading.
Therefore, I was hoping that there was someone out there who had already dealt with this.
Maybe we should continue this thread by defining the experiment and how it can be performed?
Brian, “The Enchanter”
I just purchased a $12 indoor/outdoor thermometer that reads to the tenths of degrees in the auto section at Walmart. Buy 2 stick the outdoor probe of each into the two containers and check on a regular basis. Tenths of degrees should be enough to perform this simple task.
You don’t need accuracy, you just need precision.
Buy one of those dual indoor/outdoor thermocouple-type thermometers.
Get a bucket of ice. Let it sit around until the ice is melting nicely.
Stick the “outdoor” thermocouple into the melting ice. The temperature should be around 32 degrees F.
Take it out and warm it up. Then put it back into the ice. See if you get the same temperature. Repeat this several times, and you’ll get an idea of how precise the thermometer is (that is, how repeatable its temperature measurements are).
NOW do your experiment. See how long it takes for the contents of the can to warm to some specified temperature. You can use the “Indoor” thermometer to make sure the ambient temperature is fairly constant.
See what the difference is for plastic and aluminum.
Now, realize that you haven’t actually proved anything, because unless the cans are exactly the same dimensions that might affect the results. Consider how you might repeat the experiment to minimize this factor. I’m thinking styrofoam cup with the bottom cut out and replaced by a plastic or aluminum disc of identical size.
I’m pretty sure that unless you bias the experiment in some way, you’re going to get the same answer that most people here gave you (and that you don’t seem to like): plastic is a better insulator than aluminum is.