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Crazy Facts | Water Heater Pros | Sacramento, Ca

Crazy Facts

image hot & cold water



A liter of cold water will weigh more than a liter of hot water. Most liquids, not all, become heavier as they grow colder. The answer all boils down, nay cools down, to density. The colder the water is, the denser it is. Density will normally determine the weight of two liquids which have the same volume. It is quantified by mass devided by volume and here on our planet Earth, mass is the same as weight. In the case of water, aka H2O, the weight is measured by the number of H2O (2 parts hydrogen, 1 part oxygen) molecules present in a given volume.


So, assuming you have two bottles-each 1 liter-and you fill one with cold water and the other with hot, you will notice that the cold water bottle is a bit heavier than its counterpart. The reason is because molecules in hot water are spaced further apart and this means fewer molecules are present in any given volume, hence leading to less mass, or weight if you rather.

image water boiling on stovetop
Hot vs. Cold Water: Boiling Experiment



The purpose of this experiment is to find out whether hot water or cold water will start to boil first if heated under the same conditions. 



Common sense would yield that the hotter the water, the quicker it should boil, because it is already closer to the boiling point, but the hypothesis of this experiment will stray away from such  nonsense and contend that the colder water will boil before the hot water, because it's rate of temperature will increase faster then the hot water, and ultimately pass it up.



This experiment will require a pot, a heat source (Stove), a measuring cup, stopwatch, a cooling source (fridge), pen and paper, source to get hot and cold water, tea bag and coffee cup optional.



The first step is to measure out three cups of water, and place in the fridgerator to chill. Then measure out 3 cups of hot tap water and place in the pot and turn on the flame, while starting the stopwatch. When boiling occurs, stop the watch, record the time. Dry the pot, and allow it to return to room temperature. Repeat same process once cold water has been allowed to chill, record results, and compare.



Water Type: amount of time water took to boil


Hot Tap Water 3 Cups, 3 minutes, 4 seconds

Cold Tap Water 3 Cups, 4 minutes, 17 seconds


Room temperature was at 69 degrees Farenheit, and the barometer was registering 30.21 inches.



The experiment has shown that common sense once again prevails, and hot water boils much-much quicker than cold water.


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image hot and cold water faucet



Back in the 19th century, when indoor plumbing was introduced, water was brought into the home by hand pump. At the time, there was only one option that came out of the hand pump: cold water. Since most people were, and still are right-handed, the pump was placed on the right side of the sink.


Instant hot water was introduced many years later. With the cold water pump already occupying the right side of the sink or tub, the logical place to put the hot water faucet was on the left side of the cold water faucet. There you have it!

image hot and cold water cups


This phenomenon has been observed for centuries but was not properly introduced to the scientific community until 1969. Since that time, it has commonly been referred to as the Mpemba effect, named after the Nigerian high school student who rediscovered this back in the 60's.

Mpemba first noticed this back in 1963 when making ice cream for a school project.The students mixed boiling milk with sugar and told to let the milk cool before refrigerating it. Impatient, Mpemba disregarded directions and put his milk in right away without letting it cool. Inexplicably, his milk cooled before the rest of the class! But, his physics teacher said this was not possible.


He later found that the local ice cream venders did the same thing to speed up the freezing process! Mpemba was still critcized at school for his "bogus" science, even though he had hard evidence with which he could back his theory up. A physics professor later visited the high school and heard what Mpemba had to say. He replicated the process and couldn't explain the phenomenon either, so he and Mpemba published their results in 1969.

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Did you know?

The first water heaters were tankless!

A copper coil was heated by the burners below as hot water demand was needed.

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