# Which cup of tea cools down more quickly?

There are 2 cups (both cups are identical) of tea which are served at the same temperature. Assume that the walls of the cup to be non-heat conducting. Which cup of tea cools down faster, a full-filled glass or a half-filled glass?

According to what I think, The walls of the cup don't make a difference and neither do the top and bottom surfaces. The only determining factor would be the volume of the tea. So what I came up with is that, somehow the cooling process by convection will be affected by the volume of the tea in the cup but I'm not sure about my above assumption and even if it's true how will the volume of the tea affect the cooling process by convection within the volume of the liquid?

Taking the initial temperature higher than the room temperature.

• Let the "same temperature" be 60 degree celsius and room temperature 25 degree celsius. Sep 23 '17 at 9:47
• Useful read: [ en.wikipedia.org/wiki/Newton%27s_law_of_cooling ] Sep 23 '17 at 9:48
• Anyway, what do you think determines the heat exchange rate in this case, and then what determines the resulting temperature change?
– user7951
Sep 23 '17 at 13:25
• @Loong I think that there will be heat exchange between the open top surface and the hot tea due to which convection will occur within the liquid volume Sep 23 '17 at 13:27
• What shape does the cup have? Sep 23 '17 at 15:36