
Hydration, Water, and Salts
It’s early July and you’re out for a night hike in the hot, dry Sonoran Desert. You weave your way between cactus and brittle bush, carrying a large pack of water with you. Without water in this desert, you could die within hours to days. Coming around the side of a prickly pear cactus, you suddenly see a small dark shape that stands out in your headlamp. And it certainly sees you—it hisses. You’ve surprised a Gila monster, a venomous lizard found only in North America.
Why Do We Get Sick?

Crazy Climate and Wacky Weather
Climate is a hot topic in the news and on internet websites and blogs. But what exactly is climate? And how do we know it is changing?
Also in: Español
Wings in a New Light
The peppered moth lands on the bark of a tree trunk and opens its wings to rest. A hungry flycatcher bird that was close behind swoops down for a meal but loses sight of its prey. The moth blended in with the tree trunk. Blending in let it avoid the pesky flycatcher, so the moth lives to see another day. This may seem like a simple act of nature, but scientists are quite curious about how and why these sorts of interactions arise.