1)I have noticed a physical phenomenon that is fairly consistent if I repeat the process in varied surroundings. This situation is this: I fill a wash basin that has a removable plug, pull the plug and record the length of time required for the basin to empty. I can repeat the exercise filling the basin from either the hot or the cold tap. I notice that the time to empty is consistently less if I initially fill the basin with cold water. What is the explanation for this observation? 3) The hot water is denser than the cold water once it cools which leads to an increase in Reynolds number. This signifies greater turbulence which leads to more skin friction on the walls of the basin, therefore causing the hot water to drain slower.