Online learning is on the rise in the nation's public schools. In the year 2000, roughly 45,000 K-12 students took an online course. In 2010, roughly 4 million did, according to Ambient Insight .

Learning about science online and at home (AP Photo/Jim Mone) ASSOCIATED PRESS. Online learning, once reserved for higher education, is now a growing trend among K-12 students nationwide.