Scientific American is the oldest continuously-published magazine in the United States -- older, even, than the industry's other elder statesman National Geographic. The magazine has stayed at the forefront of its field by bringing science news and trends to readers in an authoritative manner, but in a way that laypeople can follow.

What to pitch: News editor Philip Yam edits the "News Scan" section in the front of the book and hires the bulk of its freelancers. The 500- to 800-word pieces comprising the section report on a wide variety of subjects and tend to focus less on the technologies that the feature well covers comprehensively, and more on basic sciences. Since the magazine is a monthly -- and because scientists frequently decline to discuss their work until it's published in a peer-reviewed journal -- Yam is "less interested in breaking science news stories."

What not to pitch: A section of briefs at the end of the news section -- they're so short they're not really worth pitching, Yam says. "By the Numbers," "SA Perspectives," "Anti Gravity," and "Skeptic" columns are primarily written in-house. As for book reviews, if you happen to have been a grad student in oceanography and there's a hot new release about a region at the bottom of the Atlantic, it's worth a shot -- but, know that the majority of reviews are written by experts, not freelancers.

Get many more details here.