The large container of water will melt more, of course, so you know it contains a different amount of heat. Heat tends to move from a region with higher temperature to a region with a lower temperature just as a ball tends to roll downhill. You must give a ball more energy to move it uphill and more energy is required to pump heat from a cooler region to a warmer one. Any of these can be used to measure heat. As you go to higher and higher elevations above sea level you come under less and less pressure.
Less pressure means a lower boiling point and more pressure means a higher boiling point.
In general, the boiling point decreases 1 o C for each 1,000 ft increase in altitude. The temperature of a pot of boiling pot of water remains the same until the water boils away. Boiling is evaporation that occurs theroughout a liquid. Increasing the rate of heating will increase the rate of boiling, so evaporation will occur more rapidly. Evaporation is a cooling process, so overall the temperature remains constant.