Weather Wise: Easy Frost Science Experiment

As we were getting ready to leave for school the other day, Princess opened the door and shouted, “Snow!” But, it hadn’t been snowing at all. It was actually frost that formed on the car overnight, which inspired us to do a frost science experiment.

Weather Wise: Quick and Easy Frost Science Experiment Share on X

Her new discovery sparked a conversation about how frost forms. Explaining anything science related can be tricky when it comes to a 5-year-old. However, the key is to leave out the complicated jargon. Here’s a scientific, but simplified explanation:

Frost can happen on a cold, clear night with light winds. Since cold air is more dense than warm air, the water vapor in the air sinks to the ground and condenses. Because the ground is at or below 32 degree Fahrenheit, it freezes on contact.

Keep in mind that the air above the ground is warmer and more humid. The temperature difference is also needed to allow frost to form. This explains why you’ll see frost on your windshield, grass, trees etc.

Here’s what I told my 5-year-old:

When you can see the stars in the sky on a cold night and it’s not windy, there are tiny water drops – like steam from a hot shower – all around us that you can’t see. These drops make their way to the ground and freeze because the ground is so cold.

“What happens when you put water in the freezer?” I asked.

“It becomes ice,” she answered.

To further explain this how frost occurs, we did a cool experiment. If you decide to try this at home with your kiddos, here’s what you’ll need:

1 can

3 tablespoons of salt

ice (enough to fill half of the can)

spoon

Directions:

Place ice inside of the can, add the salt, and stir. Wait about a minute and watch the frost develop outside of the can.

Explanation

Even though the salt melts the ice, the mixture is below freezing. The moisture from the air outside of the can and that’s how frost forms!