To raise the temperature of water in a thimble of water from 0 to 100 requires a small amount of thermal energy. To do the same with a swimming pool would require putting a huge amount of thermal energy into the water comparatively speaking.
BOD5 values are calculated at a fixed temperature as described in "Standard Methods for the Examination of Water and Waste Water" Highrer temperatures would lead to higher (wrong) values.
The liquid with a lower density float over the liquid with a highrer density.
The normal boiling point of ethanol is 78.4 degrees C and, at this temperature, the vapor pressure is 101,325 Pascals (Pa) or 760 manometric units (mm Hg), which is a pressure measurement using a millimeter of mercury.