How Does Water Freeze
As a kid, I thought ice was simply cold magic, in reality it is science, chemistry, thermodynamics and physics.
Freezing is the process of changing from a liquid to a solid. For water (H2O) that temperature is 32 degrees Fahrenheit or 0 degrees Celsius, and you might think that all water would freeze at exactly that temperature, however there are a number of factors, conditions and reasons why water does not always freeze at the same temperature. Water is at its densest at 39.2 degrees Fahrenheit. Water molecules slow down and rearrange into crystals. In order to form crystals they need a seed to grow around (this is called the nucleus). So if there are NO impurities in the water, it won’t freeze as fast.
The depth of water is also a factor, two lakes with the same surface area and one is deeper than the other, the shallower one would freeze first. This is well displayed since North Pond typically freezes before South Pond.
Lake water freezes from the top down, due to the oxygen or air entrapped inside during the freezing process. The trapped air provides a nucleus for the crystals to form around. Freezing is really the loss of heat energy.
If you have ever had your water pipes freeze and burst, you unfortunately proved that water expands as it freezes, and this can result in a very significant force.
What factors can contribute or slow down to the freezing process?
Air Temperature:
Water depth: the deeper the water body the slower it will freeze. The longer it takes for the water to lose thermal energy and to cool enough to freeze.
Water movement: Both wind or current affect the rate of freezing. Water that is moving will not necessarily freeze at 32 degrees. The energy or shock of moving water breaks up the crystallization process, thus prevent the ice crystals from forming
Salinity, Chemicals, Contamination and Oxygen levels: can also have an effect. Salt water will not freeze as fast as fresh water. Suspended solids: It will take perfectly pure water longer to freeze than it will for lake water to freeze because of the absence of impurities which are needed for the formation of the crystals around the nucleus.
Radiation from the sun's energy: Solar radiation can heat up surface water to keep it from freezing. Why does ice make noises when it is frozen? The simple answer is either expanding (freezing) or contracting (melting) or it is under some stress causing it to fracture, crack or break. So, if you are out on the lake and hear that cracking rumble you should hope that it is below freezing conditions and the ice is expanding and not because you are on thin ice.
In conclusion, ice is not magic, but rather magical. There is a magical beauty when open water freezes crystallized and creates a whole new atmosphere around the lake and allows for skating, ice boating, walking, cross country skiing and ice fishing and then it is transformational again in the warmer weather of spring and the ice yields and gives way to the open water. That will be the moment when Norpondapus falls into the water and there is a winner! Spring ushers in summer, providing new life and energy filled with the hopes of fishing, kayaking, boating and swimming.
If this is more than you ever wanted to know about ice, just go out and enjoy it!