Ice cubes design

[Zielin]

Hi, I'm doing a design on cooling abilities of ice cubes and I would appreciate it, if you could help me with this a little. In my experiment, I was immersing 1, 2, 3, 4 and 5 ice cubes (those are my independent variable) in a hot (80C) tea. Then, after one minute I checked what the temperature change was. I don't think my results are very consintent, and therefore, I would like to ask what kind of relationship between the rate of cooling and number of ice cubes would you expect from such an experiment and what factors do affect this rate.

[Dr. Jenkins]

You should be able to calculate that on your own:

Warmup of Ice Cubes + Melting of Ice Cubes + Warmup of Melted Ice Cubes = Cooling of Tea

Use:

Q = mc(Ti - Tf)

Q = mL

Tea would have a specific heat capacity pretty close to that of water, and the difference might be negligible.

Of course you cup is well insulated and does not loose any heat, otherwise you don't have a closed system.

Edited November 22, 2012 by Dr. Jenkins

[Zielin]

I know all the equations and stuff, I meant more subtle things, which can have influence. For example, 1 cube will disappear completely after, say, 30 seconds, and after this time it will not have any impact on the tea any more. However, 3 cubes will cool this tea for the whole time taken into consideration (i.e. 1 minute). I'm not sure what kind of relationship (linear? some other?) should there be between the number of ice cubes and the rate of cooling?

PS - the system was allowed to exchange energy with the surrounding

Edited November 22, 2012 by Zielin

[Dr. Jenkins]

Well, dig out a thermometer and a stop watch and see for yourself.

One idea though is that the surface area of the ice cube shrinks much like a radio active decay curve. But I think this is much too complicated thinking for this model.