[Rowman Gentles]

Rowman Gentles asked the Naked Scientists:
   
What is the specific heat capacity of tap water and brine?

Which one cools faster and why?

What do you think?

[RD]

Water (liquid): cp = 4.1855 J/(g·K) (25 °C)

http://en.wikipedia.org/wiki/Specific_heat_capacity

Mechanical and thermal properties of sea water at salinity 35 g kg⁻¹ and atmospheric pressure (unless otherwise stated)

Specific heat capacity, Cp   ... 3993 J kg−1 K−1 at  20 °C

http://www.kayelaby.npl.co.uk/general_physics/2_7/2_7_9.html


I think salt (sea) water will cool quicker from a given temperature as it has a lower heat capacity than pure water: if the respective containers* of water lose energy to the environment at the same rate then the salt water's temperature will drop quicker because it contained less heat energy to start with because of its lower heat capacity.

(* the containers and the quantity of water in them must be identical for a fair comparison).