Condensation nuclei, DYK Fact #356

[Athene_noctua]

Did you know? Before a cloud can produce rain or snow, rain drops or ice particles must form. This requires the presence of aerosols: tiny particles that serve as the nuclei for condensation.

Most such particles are of mineral origin, but airborne microbes – bacteria, fungi or tiny algae – can do the job just as well. That’s right: the same bacteria that cause frost damage on plants can help clouds to produce rain and snow, as Nature News reports.

[Sophie]

I have just read about condensensation nuclei in The Concise Oxford Dictionary of Geography. Did you know? Condensation nuclei, which may be particles of dust, soot, salt, or, in the Bergeron–Findeison theory, ice crystals, attract water droplets which coalesce to form a raindrop, which will descend when its fall speed is greater than the velocity of upward air currents in the cloud where the condensation nuclei are found.

[Sylvia]

I have just read about cloud in the glossary at the end of Chapter 2, “Earth and its resources”, under the section THE PHYSICAL UNIVERSE in Volume 1, “The world of nature”, of the Reader’s Digest Library of Modern Knowledge. Did you know? “Clouds cannot form in very dry air, and they form more easily when the air is cool.” Warm, moist air rising through convection currents produce cauliflower-shaped cumulus clouds; other cooling processes form different types of clouds.