What are Convection Currents?

Convection currents are everywhere. They power our weather patterns and convections currents. What are they and how do they work?

To be honest, I started to write about why snowstorms in the US tend to travel from West to East, but realized that would be an entire month’s worth of blog posts. I’ll get there eventually. Here’s the first part.

First, let’s talk about density. Density is a measure of how tightly packed together the molecules in a substance are. Usually, when we heat up a substance, its molecules start moving faster and spread out more and more.

This takes us to Rule 1: Warm air is less dense than cold air.

What does this mean when warm air and cold air are hanging out together? Since warm air is less dense, it is a little lighter in every square meter, so it tends to float on top of cold air. Thus, Rule 2: Warm air floats on top of cold air.

That’s not the end of the story. When warm air rises, it is often moving away from the source of heat. When we’re talking about convection currents in the atmosphere, the heat source is usually the earth, which is radiating heat it has absorbed from the sun. As the warm air rises away from the earth, it begins to cool off…and get more dense…and start to sink back towards the earth. The air then gets warm again, and the whole cycle restarts.

This creates a convection current that will continue to cycle around as long as there’s a heat source at the bottom.

Stay tuned to learn how convection currents contribute to weather patterns.