Raindrops Should Not Be Possible

Excited for the August 21 eclipse? Visit our Eclipse 2017 page to explore the science, history, and myths of the event. The Curiosity team will be viewing the eclipse alongside NASA in Carbondale, Illinois. Follow us on Facebook for live videos, trivia, and interviews on the big day.

A lot of physics sits inside one tiny raindrop: cohesion, adhesion, and air resistance, to name a few. Of course raindrops exist, but the mathematics behind them doesn't quite line up. Surfaces require more free energy to make than volumes, which is why small water droplets pose a problem. If a water droplet is below a certain size, then making it bigger requires more surface energy than is released from volume energy, which means it would take energy for the droplet to grow—but it doesn't, it shrinks. To help understand this, think about small decimal numbers: squaring and cubing them actually makes them smaller, not larger.

Share the knowledge!

Key Facts In This Video

  1. Falling raindrops are more often shaped like jellyfish than teardrops. 00:05

  2. Surfaces require more free energy to make than volumes. 00:41

  3. If a water droplet is below a certain size, then making it bigger requires more surface energy than is released from volume energy. 01:24

If you liked this you'll love our podcast! Check it out on iTunes, Stitcher, Google Play Music, SoundCloud, search 'curiosity' on your favorite podcast app or add the RSS Feed URL.

Advertisement