Photo: Surprising Clouds Forming Due to Lead in Air



Researchers collected cloud samples atop a mountain and found that about half of their ice crystals contained lead. Then, by building artificial clouds in laboratory chambers, the team determined that lead actually causes ice crystals to form.


Photograph by David Alan Harvey


NEWS FEEDS    After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed. After installing a news reader, click on this icon to download National Geographic News's XML/RSS feed.

Get our news delivered directly to your desktop—free.
How to Use XML or RSS

ADVERTISEMENT

NATIONAL GEOGRAPHIC'S PHOTO OF THE DAY

50 Drives of a Lifetime

Listen to your favorite National Geographic news daily, anytime, anywhere from your mobile phone. No wires or syncing. Download Stitcher free today.