Rain rain.. go away..

Look up. Is it raining? No? Stop reading then, you’re already too late.

Look up. Is it about to rain? Yes? Good! Keep reading.. you’re about to learn all about rain and forces and other super cool science stuff!

First, we need to understand what rain is. It’s water dummy.. (how could you not know that already?) but really, rain is condensed gaseous water vapor that falls to the surface of the Earth (usually.. more on this later..) because the upward moving air (wind) keeping it airborne becomes too weak, so gravity takes over and causes it to fall down. Whether the water becomes too heavy for the wind to keep it up, or the wind becomes too weak to keep the droplets up, gives the same result.. a rain storm.

Water however is very heavy. So heavy that one cubic foot of water is just under 62.5 pounds. To give you some context, one cubic foot of lead is about 708 pounds, and one cubic foot of sea-level air is about 0.08lbs. Taking the weight of water into context, realize that clouds are thousands of cubic feet in volume, so they weigh a lot.. thousands of tonnes in weight, so the air rushing upwards must be ridiculously fast, and strong right? Finding definitive results was difficult, the closest I could find was an 80m wind measurement with an average global speed of roughly 24km/h. Because everyone likes numbers and math, I’ll throw in that at the summit of Mount Everest (29,025 feet above sea level), it averages at 280km/h. Now, the summit of Mount Everest is well above the average cloud height in North America, so yes, the wind speed is not as high as that, but in just under 30,000 feet, the wind speed multiplied. Many many times.

With the amount of upward wind thrust, yes, keeping the thousands of tons of water in the air is easy for the Earth, because of the speed generated, but also because the water droplets itself is almost mystified, or nearly in a gaseous state. Before I get Meteorologists and other scientists tackling me from both sides, yes I’m aware that clouds are not gasses, nor did I refer to them as gasses, rather, “almost gas”. To keep a balloon full of oxygen in the air is easy, but to keep a balloon full of water is difficult. The same thing happens in clouds.

Now, enough of how clouds work – that’s boring for many. What about the rain itself? What if all the rain fell at the same time as one giant droplet of water? My friend Randall over at XKCD answered that, and it has pictures.. something this blog post is severely lacking. So..


Jeff Wilton

Jeff is the founder and owner of Everyday Science Stuff. ESS is a one man operation, with the core belief that all education should be served without crippling debt tuition, without revenue generating ads and without any restrictions of any kind such as paywalls, forced login and account creations, geographical restrictions, and so on.

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