Most of us need no reminding that winter time is here. This year’s winter has been one for the record books with cold temperatures and huge snowfall totals. We should have know we were in for a wild winter when parts of the Deep South got snow on Christmas, and the northeast part of the United States was buried under 2 feet of snow. There has been one snow storm and arctic blast after another, leading to the past weekend's frigid temperatures from the Midwest to Northeast.
This last arctic blast was not stereotypical cold winter air, but presented people with temperatures that are normally reserved for locations close to the Arctic Circle. Most of us stayed inside, trying to keep warm. Experts said exposing skin for more than 10 minutes would lead to frostbite. Thankfully, a few brave people ventured outside to conduct a little science experiment.
Something science teachers, kids, and adults see as a fun thing to do when we have this extreme arctic air is to throw a cup of hot water into the air. The key to getting the water to vaporize is to use boiling water. Also, the outside air temperature has to be at least -15 degrees below zero. Believe it or not hot water can freeze faster than cold water thanks a scientific phenomenon called the Mpemba Effect. In essence the “Mpemba effect” states that, in certain specific circumstances, warmer water freezes faster than colder water. To see this actually working, take a jar or cup, and fill it with boiling water. Then take the cup or jar of boiling water outside, and throw it all up into the air. As the boiling water meets the sub zero cold (at least case -15°F) air, the water will instantly vaporizes. Most of the water is turned into a cloud of steam that drifts away, but some of the droplets that stay together are instantly turned into small pieces of snow/ice that can be seen falling to the ground.
There are numerous other ways to use the current cold arctic air for some further experimentation. To help school kids understand volume, you can take various container sizes of water (1/2 cup, full cup, ½ gallon, ect), let it sit outside. Ask each kid to predict how long it will take each on to freeze, and time how long it takes each one to freeze, and see who gets closest. Another neat experiment that kids like is to see how long it takes different fluids to freeze. Put various liquids outside and see which ones freeze and which don't. You can use try different liquids like alcohols, which have lower freezing points, and oils like mineral oil and olive oil for different results.