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Raindrops, Tears, and The Real Shape of Rain

When you draw a raindrop, what shape is it? Does it look like a teardrop? Probably. In reality, rain drops don’t look like the way we often draw them. Let’s explore the physics that determines the shape of rain as it falls from the sky.

 

Profile picture for user WeatherPro
WeatherPro
16 May 2019

Raindrops, Tears, and The Real Shape of Rain

When you draw a raindrop, what shape is it? Does it look like a teardrop? Probably. In reality, rain drops don’t look like the way we often draw them. Let’s explore the physics that determines the shape of rain as it falls from the sky.

 

Profile picture for user WeatherPro
WeatherPro
16 May 2019
4 min read

Everywhere you look, you will find images of clouds raining tears. Clipart, clothing, jewelry, mugs, shower curtains, bed sheets. The teardrop shape has become synonymous with the shape of water. It would seem that there are a lot of really upset, sad clouds out there.

Raindrops don’t actually look like the clip art images you might see on your shower curtain.

In reality, raindrops don't look like teardrops at all. Gravity, air resistance, and surface tension all influence the shape of a raindrop as it falls from the sky. Small raindrops are spherical. Bigger ones look like domes, or hamburger buns.

Clouds [link to cloud article] form when water vapor condenses around tiny dust particles in the air. The early water droplets in clouds are so tiny that they can float, suspended in the air. However, as these droplets begin to collide, they form bigger droplets. Eventually, these drops are too big to stay afloat and they fall to Earth as rain.  

Here you can see the stages of a raindrop as it grows:

1. The droplet is tiny. The surface tension of the droplet holds the water in a spherical shape.

2. The raindrop has enlarged in size after bumping into others. Air resistance pushing against the larger droplet as it falls causes it to look like a little hamburger bun. 

3. The raindrop is getting pretty big now and having trouble keeping its shape. The force from the air is now trying to split it apart. Raindrops much bigger than this rarely remain together during freefall.

4. The raindrop has become too large. As it falls, the air pushing on it breaks it apart in two. The process will begin again as the smaller ones continues to fall and collide with other drops.

 A raindrop that falls into dry air will evaporate. Rain that doesn't reach the ground is known as virga. If a raindrop falls into air below freezing, it will become some sort of winter precipitation. Winter precipitations can vary from snow to sleet to freezing rain depending on the temperature of air it falls through.

So remember, the next time you see a crying cloud, try imagine little hamburger buns falling from the sky instead. Maybe the cloud won’t be so sad anymore.

 

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About the author

Profile picture for user WeatherPro
WeatherPro

At WeatherPro, we believe that good things happen when people step outside and great things happen to those who are prepared. We strive to empower life’s outdoor moments. #stepoutside