Freezing Speed of Hot Versus Cold Water

[bdunham7]

For this reason, experiments should not allow the sample to freeze. They should go from liquid at one temperature to liquid at another temperature.

That depends on what the purpose of your experiment is.  If you are testing the theory that one sample has a persistently different heat capacity than another, then OK.  Otherwise, and in the context of the OP's post and so on, that's probably not too enlightening.