THIS STORY HAS BEEN FORMATTED FOR EASY PRINTING
Ask Dr. Knowledge

What makes clouds white and why do they go dark just before it rains?

April 16, 2007

E-mail this article

Invalid E-mail address
Invalid E-mail address

Sending your article

Your article has been sent.

Text size +

Clouds are made of tiny water droplets. Water that evaporates and rises up into the air as vapor is actually invisible, and you can see it only after it's cooled off enough to turn back to liquid. You can actually see this effect if you look carefully at the spout of a boiling kettle of water. Just below the white ... (Full article: 290 words)

This article is available in our archives:

Globe Subscribers

FREE for subscribers

Subscribers to the Boston Globe get unlimited access to our archives.

Not a subscriber?

Non-Subscribers

Purchase an electronic copy of the full article. Learn More

  • $9.95 1 month archives pass
  • $24.95 3 months archives pass
  • $74.95 1 year archives pass