In our last blog post, we asked whether the weather (or is that weather the whether?) could be controlled by human means one day. It turns out that this day may be here, thanks to “cloud seeding” technology. In this blog post, we’ll look at the details involved more closely and learn how cloud seeding may just save the next summer Olympic games!

So how does cloud seeding work? In order to seed a cloud, humans add materials to the sky where they want water droplets to form. Sounds pretty simple so far doesn’t it?  Maybe, maybe not. Let’s look at China for example. China has tons of pollution. In fact, it has more air pollution that any other country. Some days, the air is actually brown and hard to see through because it is so full of fine particles due to pollution from manufacturing and industry. China produces a lot of manufactured goods that are shipped to North America. Think about it: How many things have you seen that say “Made in China” on them? But does it rain more in China due to all this pollution? That’s a tough question. In some cases, air pollution can decrease the amount of rain that falls. Why? If the particles in the pollution are very small, the water droplets that form will also be very small. Such small droplets will hang in the air longer and be less likely to fall as rain! This is because the heavier the droplet, the harder it is to for it to stay afloat up in the sky!

For this reason, when clouds are seeded, scientists add special chemicals to the air that work especially well in forming rain clouds. Dry ice (frozen carbon dioxide) and silver iodide are two of the chemicals they use to do this. China is putting their hopes in these chemicals, so that athletes will have clean air to breathe for the next summer Olympics. How does this work? Rain washes pollution particles out of the air. So the more rain, the cleaner the air, and the easier it is for athletes to get oxygen and perform well. Let’s hope it works. Otherwise, the athletes won’t be breaking any records. And they will be coughing and choking their way to the podium to receive their medals!