Imagine that you have just purchased a coffee in a cup, with a lid. you place your coffee cup on a table and it starts to cool down. we are going to model this cooling process. choose whatever type of coffee cup you are most familiar with.
* once the sides have warmed up, calculate the outside surface temperature of the sides of the cup, and the heat flow through the sides of the cup. you may neglect radiation from the outside of the cup.
the specific heat capacity of water (and coffee) is around 4200 j kg-1 k-1. cardboard has a thermal conductivity of around k ~ 0.025 w m-2 k-1 , a density of around 700 kg m-3 and a specific heat capacity of around 1400 j kg-1 k-1. glass has a thermal conductivity of around k ~ 1 w m-2 k-1, a density of around 2500 kg m-3 and a specific heat capacity of around 700 j kg-1 k-1. styrofoam (foamed plastic) has a thermal conductivity similar to air and a density of around 50 kg m-3, while hard plastics have thermal conductivities of k ~ 0.025 w m-2 k-1 and densities similar to water: both have specific heat capacities of around 1500 j kg-1 k-1.