I will be away from social media for a little bit so two quick updates:
– I had a small accident yesterday coming back from the visa office. I’m perfectly all right; at worst, I’m mildly concussed but most likely just a lot stressed over the whole situation. Mine is a cautionary tale about not driving over 10 mph in bad weather and also making sure you have good tires.
– I was picking up my visa to go to China, where I will be spending the new year for the first time! I haven’t seen my extended family in nearly 4 years, so I’m very excited to go back. I’m slightly less excited to have my relatives ask me when I’m getting married, why I’m so tan, and how round my face is getting.
Due to the Great Firewall of China and my general tendency to keep away from social media while I’m on vacation, I’ll be reachable by email but you may not have as much luck with everything else.
Otherwise, be back in touch with everyone in under 3 weeks!
(I have a post about my ghastly visa experience ready that I may publish before I leave, or after I come back. I haven’t forgotten about my Europe posts that are left! Please lemme know if you’d rather I put those up when I get back or my China posts first.)
All things being equal, cold water freezes faster.<bb
It takes time for the energy contained in a hot object to be transferred to a cold object. However, the rate of heat transfer is proportional to the temperature difference between the two objects, so hot water will lose heat faster than cold water. In other words, if you have water at 90 degrees C and water at 10 degrees C and the freezer is at -10 degrees C, the hot water will lose heat five times faster than the cold water; however, the cold water will still win the race. As the hot water cools it’s rate of heat transfer will decrease, so it will never catch up to the cold water.
Some people claim that hot water freezes faster because a pot of boiling water can be thrown into the air on a cold winter day, and it freezes in mid air creating a shower of ice crystals. Whereas a pot of cold water thrown into the air comes down as large blobs of water. This happens because the hot water is so close to being steam, that the act of throwing it into the air causes it to break up into tiny droplets. (hot water is less viscous than cold water, listen to the sound it makes when you pour it in the sink) The small water droplets have a large surface area which allows for a great deal of evaporation, this removes heat quickly. And finally, the cooled droplets are so small, that they can be easily frozen by the winter air. All of this happens before the water hits the ground. Cold water is thicker and stickier, it doesn’t break up into such small pieces when thrown into the air, so it comes down in large blobs.
Joe Larsen, Ph.D. Chemistry, Rockwell Science Center, Los Angeles, CA