The True Shape of Raindrops

Raindrops come in various sizes and shapes, but most raindrops are spherical or slightly flattened. When raindrops fall from the sky, they experience air resistance, which causes them to flatten out. However, they don’t become perfectly flat, and instead, they take on a somewhat oblate spheroid shape. This means that they are slightly flattened on the bottom and have a slightly rounded top.

The actual shape of a raindrop depends on a few factors, including the speed at which it falls, the temperature and humidity of the air, and the amount of surface tension the drop possesses. As raindrops fall through the atmosphere, they encounter air resistance, which pushes against the bottom of the drop, causing it to flatten out. However, the surface tension of the water molecules in the drop tries to pull the drop back into a spherical shape. This battle between air resistance and surface tension causes the drop to become oblate spheroid in shape.

In addition to their oblate spheroid shape, raindrops can also become distorted due to the wind. When wind blows against a falling raindrop, it can cause the drop to become flattened and elongated in the direction of the wind. This can result in raindrops that are shaped like teardrops or even cylindrical in shape.

It’s worth noting that raindrops are not always the same size or shape. The size and shape of a raindrop can vary based on the amount of water in the cloud, the temperature and humidity of the air, and the speed at which the drop falls. Smaller drops tend to be more spherical in shape, while larger drops are more likely to be oblate spheroid. Drops that fall more slowly also tend to be more spherical, while faster-moving drops are more likely to be distorted due to air resistance.

In conclusion, the actual shape of a raindrop is typically oblate spheroid due to the battle between air resistance and surface tension. However, other factors such as wind and the size of the drop can also affect its shape.


Disclaimer: What you just read was written by generative AI. I won’t mention which one because it just so happened to get one significant fact wrong. The claim the raindrops can be shaped like “teardrops” is flat out false. A drop of water forming under a leaky faucet can have that “teardrop” shape just before it breaks free, but once it separates surface tension quickly pulls it into a near-spherical shape.

The graphic (created by me and not AI) shows the range of shapes a real raindrop can take. The shape is determined primarily by the size of the drop. Note that the drops are shown in 2D cross-section. The >4.5 mm drop does not separate into two drops, as it seems to show. It’s actually stretched into an “inner tube” shape with a “parachute” of thin water above it. When the parachute is stretched too thin it breaks, and the remaining ring of water can separate into three or more drops.

Why did I use AI to write the first part of this post? Truth be told, I was curious to see how well it could do on a relatively simple topic. My request to the AI was: Write a simple 300-word explanation of the shape of actual raindrops. Most of what it wrote wasn’t bad, but this just goes to show that when AI trains on the internet, it’s going to dredge up some incorrect statements.

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2 comments on “The True Shape of Raindrops”

  1. A red flag popped up when I read the word “teardrop”. I thought at the time, what is the shape of a teardrop? The other forces such as friction with the skin come into play with forming a teardrop. Other than that you may get a week off now and again.

    Did you see the 60 Minute bit on Google’s AI this past Sunday? Totally self sustained, no connection to the Internet, quite impressive.

    1. Other readers said it just didn’t “read like my usual writing.” And yes, I have been closely following the developments in AI in various media, including 60 Minutes. This post was just an experiment. I promise I won’t do it again. 🙂

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