十萬火急~~~HELP

you should stir well the water when measuring specific heat capacity because you want to have a even distribution of temperature
so the temperature you measured by the thermometer is the same as that of the water

also, this can reduce some effect of heat loss to surroundings

If the water is not be well stirred, the temperature of the cup of water will not be even.

The part near the fire/ hot plate will be at higher temperature while those away from the fire will be at lower temperature. Thus the temperature is not evenly distribute in the cup of water.