Ice Ice Baby
Did you know that hot water actually freezes faster than cold? Strange right? One would think cold water would freeze faster given that it's already somewhat closer to freezing temperature. This "hot water freezing faster than cold" is known as the Mpemba effect.
But as I mentioned in a previous post, sometimes what seems to be the most logical answer a) isn't the answer and b) isn't so logical.
Physicists from Nanyang Technological University in Singapore believe this effect can be attributed to the chemical bonds that hold water together (i.e. hydrogen bonds).
They report that water molecules in close contact cause the molecules to repel from each other (like with a magnet), resulting in the stretching of the covalent bonds. As the liquid warms the hydrogen bonds stretch and the water becomes less dense. This stretching allows the covalent bonds to give up their stored energy, resulting in freezing.
If this is true we can presume the same process is active before the final freezing. We can do a fast and dirty experiment and find out if this is true. Take a 1 cup of cold water (from the sink) and 1 cup of hot water. Measure the temperature of both and separately measure the temperature of the fridge (should be colder than the cold water). Place both in the fridge. Which cools down to the temperature of the fridge faster? Let me know if the experiment works for you!
And there ya have it. Another mystery mayhaps solved except not really. It's a working theory, sure, but they haven't actually proven this is the case. Unless we see some molecular structures I'd say this case is still open.
But as I mentioned in a previous post, sometimes what seems to be the most logical answer a) isn't the answer and b) isn't so logical.
Physicists from Nanyang Technological University in Singapore believe this effect can be attributed to the chemical bonds that hold water together (i.e. hydrogen bonds).
They report that water molecules in close contact cause the molecules to repel from each other (like with a magnet), resulting in the stretching of the covalent bonds. As the liquid warms the hydrogen bonds stretch and the water becomes less dense. This stretching allows the covalent bonds to give up their stored energy, resulting in freezing.
If this is true we can presume the same process is active before the final freezing. We can do a fast and dirty experiment and find out if this is true. Take a 1 cup of cold water (from the sink) and 1 cup of hot water. Measure the temperature of both and separately measure the temperature of the fridge (should be colder than the cold water). Place both in the fridge. Which cools down to the temperature of the fridge faster? Let me know if the experiment works for you!
And there ya have it. Another mystery mayhaps solved except not really. It's a working theory, sure, but they haven't actually proven this is the case. Unless we see some molecular structures I'd say this case is still open.
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