Does hot water freeze slower than cold water?
Its a hot day and all you want is a block of ice to suck. Then you realize that was the greatest idea you made this summer. You think of getting some water, put it in a popsicle mold and freeze it. You go to the kitchen to find hot water, not cold. There are no water bottles, the filter on the tap is broken, so you have to heat water to make sure its clean. You decide you can wait for the water to freeze (even if it is hot), so you put in the popsicle mold and let it freeze. Then after sometime your impatient self, can’t wait for the ice to freeze (even if it has been 2 hours), so you look into the freezer and find your water popsicle to be frozen. You are now you are shocked because, you didn’t expect it to freeze. You now wonder, does hot water freeze slower than cold water. Lets pop this balloon to find out!
What is water?
Water is one of the main things people and all living things need to live. It is made out of two hydrogen molecules bonded with one oxygen molecule. The two hydrogen molecules are on the same side, at a 104.5°. Since the ends of a molecule carry opposite charges, the water molecules stick together. Water is also known as a universal solvent, since it dissolves things, because the charged ends surround and pull solutes. The word water comes from the Old English word watar, which traces back through Proto-Germanic watōr to the Proto-Indo-European root wódr̥. This means wet or water. This word has maintained in recognizable form, for something about six thousand years.
Does hot water freeze slower than cold water?
This myth is half-true. Normally hot water takes much longer to freeze than cold water. Although there is a claim stating that hot water takes less time to freeze than cold water. This effect is called the Mpemba effect. Erasto Mpemba, a Tanzanian student, noticed this effect while making ice cream. Mpemba and Osborne subbmitted evidence for this effect in 1969. Some found the effect to work while others found it a complete waste of time. Although, there are many factors that could make the Mpemba effect possible. It could be because of evaporation (which affects the volume), dissolved gases (which could change water and how it conducts heat), and frost melting ( the warm water may melt frost on shelf giving contact with cold shelf).
Fun Facts
Water is the most densest at 4°C, not at the freezing point. Pure water is a really poor conductor for electricity. The dissolved minerals are the one doing the conducting. Water is one of the few substances that expands while it freezes.
University of California Physics FAQ – "Can hot water freeze faster than cold water?"
https://math.ucr.edu/home/baez/physics/General/hot_water.html
Scientific Reports – "Questioning the Mpemba effect: hot water does not cool more quickly than cold"
https://www.nature.com/articles/srep37665
U.S. Geological Survey – "Properties of water"