Watching videos online usually means goofing off. But over the past few years, millions of decidedly enterprising people have turned on their computers to watch, of all things, math and science lectures. At KhanAcademy.org, Salman Khan, a former hedge-fund analyst, narrates more than 2,700 free lessons, each about ten minutes long, on everything from polynomials to valence electrons. In video after video, Khan’s disembodied voice explains concepts as his pen swiftly draws illustrations on a digital board. Students can also work math problem sets, proceeding through a sequence that stretches from arithmetic to calculus.
Read the rest of Laura Vanderkam on the story of the Khan Academy.
[If you have not visited the Academy, a link is in my blogroll near the bottom right hand side of this page.] The Academy has more than just math and science.