Heather Sophia

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Weather Lab: How Fog Forms!

Fog is essentially a cloud in contact with the ground.

But how does it form?

As a chemistry instructor at the Mississippi University for Women, Kaye Truitt understands elements and uses her lab to show when some of these elements unite, what appears to be magic, is really science in the works.

“So we have solid carbon dioxide that we commonly call dry ice. It’s very very cold, so you never want to touch this with your hands. As we add it to the water we will immediately being to see the fog, ” said Kaye Truitt, MUW Science Teacher.

Think of the tub of water as a lake or a river, it’s a source of moisture which is an ingredient needed for fog. Then, add cool air to the mix and it condenses. That creates fog.

When a gas, like water vapor changes to a liquid, we call this the condensation process. Fog forms in the same way. Those conditions are common early in the morning.

“Because as the heating of the day, the air is able to hold more moisture and as the atmosphere cools off, then it’s able to hold less water vapor so that water vapor that’s already present in that warmer air condenses and forms fog closest to the surface of the earth,” said Truitt.

And fog tends to sink.

“When fog does form, that’s why it stays close to the surface of the earth because the water vapor latent air is heavier than the normal atmosphere, so it stays close to the surface,” said Truitt.

So at the end of the day, if you’ve driven through fog, you can now say, you’ve driven through a cloud.

While fog can make for a slow morning commute it also makes for great pictures! If you see, snap – share it – and mention us in your caption on Instagram and we’ll be sure to share it!