Let’s briefly consider the extraordinarily high heat capacity of water. It is not a widely known fact. Well known as the compound H2O, water has a greater heat capacity8 than almost anything else you can name. It is about twice that of alcohol, olive oil, ammonia, or methane. It is nine times that of iron and thirty-three times that of gold. Since you consist primarily of water, this means that your body temperature remains constant longer in hot or cold weather than it would otherwise.2
This large amount (not intensity for that is temperature) of energy necessary to heat or evaporate water permits all animals to pant and sweat away large amounts of heat during heavy exertion or just exposure to hot weather. Water’s very high heat capacity even helps us put fires out, cooling the burning, oxidizing fuel very effectively.
Even so, the heat capacity of liquid water, arbitrarily defined as one calorie per Celsius degree, pales in comparison to its heat of fusion, e.g., the change of ice to water. Cooling things usually causes them to contract. Water is no exception, except from 4 degrees C to 0 degrees.9 In that temperature range, water expands. For that reason, lakes, rivers, and oceans freeze from the top-down, fish survive in water, and we can ice skate and drive cars over some lakes and rivers while fish live and swim below. In changing from ice to water at a constant 0 degrees C, ice absorbs 80 times as much heat as water. That makes ice eighty times as effective as cold water at cooling food and drinks in your cooler. EIGHTY times! That is impressive enough on a hot day but wait a minute.
When perspiration evaporates from your forehead, it carries off 540 times as much heat as it would by merely warming up one degree. Water’s “heat of vaporization” requires 540 calories to convert one gram of water at 212 Fahrenheit into steam at 212 degrees. Conclusion: don’t wipe the sweat off your brow. Let it evaporate instead.
At 38 degrees Celsius, perspiration evaporating cools you by 62 Calories (100 – 38) plus the 540 Calories required for vaporization per gram.
For comparison, placing one gram of a typical metal on your forehead would cool you by a few calories at best, about one-six- hundredth the cooling capacity of perspiration. -Brilliant Creations - The Wonder of Nature and Life, pages 54-55