[David, in Fincham]

David, in Fincham asked the Naked Scientists:
   
Why does an ice cold drink get warmer when its left alone, whereas hot tea appears to get colder?

What do you think?

[MikeS]

They both adjust to the ambient temperature.  The cold drink gets warmer and the hot drink colder.  The exchange of energy is always one way from hot to cold.  The cold drink absorbs energy from its environment.  The hot drink sheds energy to the environment.  The process is called entropy, which means that in a closed system entropy always increases (disorder increases).  High grade, useful energy is converted into low grade waste energy. As the process is always one way entropy is the arrow of time.