[Frith 08]

In science class we measure the heat loss in a 200 ml beaker and the results for the average heat rate was 4º per minute and a total of 32º in 8 minutes when cold liquid is added to hot liquid (coffee with milk). The hot water without the cold water the heat reduction rate was 3.5 º per minute  and in 8 minutes the toal reduction was 28º. But then I decided to exclude the amount of heat reduction in the first minute because the boiling water was º100 and the more boiling the temperature the more heat loss (steam escaping) which would'nt happen in a normal temp drinking coffee.  However my question is is their a formula to calculate the heat loss in a beaker to equal the a normal/average coffee cup size because all I got is the above to roughly calcualte heat loss rates at different rates e.g a 20º coffee reduces to 4º in 8 minutes.

[enahs]

You problem is you have heat loss by various methods.

You have heat being transferred from the water to the beaker, and then the beaker to the air. Those both occur at different rates. And you have the water to direct air heat loss. And even some heat loss from the beaker to the surface it is sitting on. And everyone of these difference surfaces are at different temperatures, and behave differently at different temperatures!


This gets pretty complicated to actually model that. And engineers will tell you, only use the model when you can not measure, as it is the best method (to measure).

[Frith 08]

Thank you for the information enahs, I really appreciate it.