How to measure temperature gradient of a point P in a closed room?

New educational networking site offers free test preparation, study help in 'Global Classroom' If you want practice taking college entrance tests, check out the free website Examville.com. But don't log off once the timer runs out. This new education megasite offers a wealth of online resources to help you with your current classes, too.

Step 1.

Post a question about neuroscience in one of Examville's dozens of Q & A boards. Download some physics study tips that another user put up. Sit in on a free live interactive anatomy review class. Or form an organic chemistry study group with fellow members. "It's just like with E-Bay, where buyers and sellers link up without any middleman," explains Examville founder and CEO Nilanjan Sen, who launched the site in time for the start of the school year. "At Examville, students and teachers can connect in an open global classroom without having to formally enroll in an institution or pay a hefty tuition. It's a new way of collaborative learning."

Step 2.

Sen, a New York-based entrepreneur whose resume includes a test prep company offering classes abroad to international students, came up with the idea when he noticed the rising popularity of online classes as well as social networking sites like Facebook and MySpace. "Most online sites use a traditional teaching model where a teacher imparts knowledge to a student. I thought, 'Why not combine the social and educational and create a community so members could teach each other and learn together?'" he said. Sen is banking there's a big market, especially as students increasingly demand expensive educational extras, such as individual tutors, private review sessions and test prep courses. But the big advantage of the Internet is that a free site like Examville allows students of all backgrounds to have equal access to the same class notes, lecture sessions, tutoring and experienced teachers, says Sen, who worked as a private math and science tutor in Manhattan during high school and college. Users can connect to people at their same academic level and at their own convenience and pace, he added. There's another section to seek advice on life matters like how to deal with a messy roommate.

Step 3.

 The site's format also allows any user to host live classes on any topic. "If you're a high school chemistry teacher in California, you can schedule your own class with live video and audio feeds and have a global student audience," he explained. "It's a true free flow of information." Examville will be supported primarily by ad revenue, and the content that is shared among members will be free. But Sen eventually hopes to introduce a subscription plan that would allow users to download certain copyrighted materials from publishers and test prep companies. Also, schools or qualified teachers would be able to charge a fee for some classes. "Initially, students will go to Examville to take the free SAT or LSAT tests, "he said. "We're hoping they'll discover what else is possible."