Everyone understands how amazing water is and how important it is to life on the planet Earth. 71% of the Earth is comprised of water and water makes up approximately 60% of the human body. There is not doubt that without water life either would not exist or it would look very different on our planet.
Not only is water important to the planet, it is also one of the most unique substances known to humans. Some of water’s special characteristics include: the only substance on Earth to exist in all three phases (gas, liquid, and solid), water is less dense as a solid than a liquid, can dissolve more substances than any other liquid.
However, one of the more fascinating properties of water is relatively unknown. Today, you are going to learn about the wonders of supercooled water and how important it is to meteorology.
What is supercooled water?
Supercooled water is when water droplets exist as a liquid at temperatures below freezing.
This phenomenon is actually very common in our atmosphere as supercooled water droplets exist in most clouds. In fact, pure water can exist as a liquid at temperatures as cold as -40°F (fun fact: -40°F = -40°C).
However, the water in our atmosphere is not pure and most of the liquid water in the atmosphere freezes once temperatures reach -4°F.
How does supercooled water occur in nature and what impacts does it have on our daily lives?
Water droplets require ice nuclei to freeze
You probably read that headline and asked: “What in the world are ice nuclei?”. Well, fret not, the explanation is not as difficult as it might sound.
Basically, water droplets require something with a similar molecular structure as ice to initiate the process of freezing. There are multiple things in our atmosphere that can accomplish this, such as: sodium chloride (salt), dust and pollen. The supercooled water droplet collides with these nuclei and the the process of freezing is initiated.
What do you think the most efficient ice nucleus is? If you guessed ice then you would be correct!
How does supercooled water affect our lives?
There a several ways that supercooled water affects our daily lives.
First, supercooled water droplets are very important in the formation of lightning. When ice crystals and hail collide in the presence of supercooled liquid water then this forms the charge that is necessary for the formation of lightning. In fact, if supercooled water is not present then it becomes very difficult for lightning to form.
Another way that supercooled water affects our daily lives is traveling by air plane. During the winter time, planes need to be “de-iced” before and after flights for safety purposes. You have probably had a flight delayed for this very reason.
Trust me, you will appreciated the reasoning for this. During the winter, supercooled water droplets can attach to the wings of aircraft and form into ice which can render the aircraft useless. The chemical that is sprayed on the wings helps to prevent freezing.
The most common example of supercooled liquid water affecting our daily lives is in the form of freezing rain. Freezing rain occurs when precipitation starts as snow in the cloud, the snow falls through a layer of temperatures above 32°F, and then falls back into a layer of temperatures below 32°F which causes the water to supercool.
Then, the supercooled droplets strike the Earth’s surface and immediately freeze into ice. This can cause major impacts on roadways and also can lead to devastating tree and powerline damage.
You can also do a fun experiment with distilled water to prove the fact that supercooled water exists. You take a bottled of distilled water and place in the freezer for several hours. Then, you can take the water bottle out and knock it against the counter and watch the bottle flash freeze before your eyes! Check out this YouTube video showing the experiment.