The Climate Classroom - Experiment 2
Colorado's Hail Problem
Colorado ranks among the most hail-prone states in the country, according to data from the Federal Emergency Management Agency (FEMA). The state consistently places between first and fourth nationwide, depending on the measurement used.
To understand why Colorado gets so much hail, I conducted an experiment demonstrating how hailstones form in nature. This is something you can do at home, too!
Experiment Setup
This experiment requires several key materials to work properly.
ICE BATH:
First, you need to create an ice bath in a large tub using a bag of ice, cold tap water, and salt. You'll also need a food thermometer to measure the ice bath's temperature and a tray of some kind.
You'll need about 1 part salt for 4 parts ice water (25%) - so don't do what I did and use a 5-gallon bucket for your ice bath! The bath should contain more ice than water.
TRAY:
You'll need a tray of some kind. I used a foil cake pan, but you can use any type of pan you want. Metal pie pan, cake pan, foil pans - anything that's flat and can hold ice easily and isn't a big mess to clean up.
DISTILLED OR PURIFIED WATER:
You'll need 2 or more bottles of distilled or purified water without electrolytes. Distilled water is ideal because it lacks particulates and minerals, but you want a 0.5 - 1 liter bottle of water, and it can be hard to find distilled water in that size. It does exist, though, at some pharmacies and grocery stores.
There aren't many brands of water that don't have electrolytes, as they change the taste profile of the water (usually adding taste and providing a specific brand identity - fun side fact). Aquafina is the closest brand you can generally buy to pure water without electrolytes that isn't distilled, and available in 0.5-1 liter sizes.
How the Experiment Works
The key to this experiment is understanding supercooling. While water freezes at 32 degrees Fahrenheit, that's not how things work in the sky! Water actually cools well below freezing and remains liquid because it needs something to condense onto to freeze, like a dust particle or, in our case, a piece of graupel or existing ice crystal.
That's why you need distilled or purified water. Electrolytes are condensation sites for water, so regular water will freeze at 32 degrees.
Ultimately, we end up with a mix of ice crystals and supercooled water drops in thunderstorm clouds.
Experiment:
Prepare the ice bath with a few ice cubes saved to the side on your tray.
Next, add salt, and stir until the temperature of the mix is down to 14 degrees Fahrenheit according to your food thermometer, which is negative 10 Celsius.
Then, put a bottle of distilled (or electrolyte-free) water into the bucket and set a timer for about 20 minutes.
After 20 minutes, carefully remove the bottle and unscrew the lid. Pour some water onto the ice chip, and watch it quickly freeze onto the surface, creating a hailstone.
One thing you should note here is that the ice you form is cloudy. This is called "dry growth". When a small piece of ice comes in contact with very cold water, it freezes so fast that the air bubbles in the ice can't escape, and the ice is cloudy.
EXTRA CREDIT:
If you want to go a step further with this experiment, take your pan with your hail, add a few drops of food dye, and put it in the freezer. Keep it there for about 20 minutes.
Take it out, and pour more supercooled water onto the stone, which should now have hardened. You just added another layer to your hail, which is exactly what thunderstorms do - creating the layers you see in hailstones.
The Science Behind Hail Formation:
In a thunderstorm cloud, supercooled water droplets crash into ice crystals or snow pellets and do the same thing. Stronger thunderstorms fling this hail back up in the cloud, where another layer of water gets added to the hail.
Eventually, the hail gets too heavy to be held up and falls from the cloud.
Why Colorado Gets So Much Hail:
Higher altitudes are colder, so we are closer to the freezing level in the atmosphere, which makes it easier for hail to form. It also gives hail less time to melt as it falls from the cloud before reaching the ground.
That's why Colorado ends up getting so much hail.
The best part of this experiment: no insurance claim needed!
____
Have a question or story idea you would like the First Alert 5 Weather team to consider? Email: weather@koaa.com
Watch KOAA News5 on your time, anytime with our free streaming app available for your Roku, FireTV, AppleTV and Android TV. Just search KOAA News5, download and start watching.