A class with tens or even hundreds of thousands of students might sound like a teacher's bad dream. But a big idea in higher education these days is the massive open online course, or MOOC. Some universities offer free, non-credit MOOCs available to anyone in the world. Others charge for courses and provide credits. The idea is still developing. So far, most massive open online courses are in computer science, technology, mechanics and engineering. For example, students around the world are taking a free course called "Building a Computer Search Engine." Two computer scientists, Sebastian Thrun and David Evans, are offering this course throughudacity.com. There are no education requirements for the course. The students watch short videos. Then, says Mr. Evans, they take informal quizzes after the videos each week for six weeks. DAVID EVANS: "Quizzes are part of the lecture to keep students engaged and keep them thinking, for students to be able to check that they understood what we covered. Those are not graded and students try those as often as they wish. They can repeatedly watch the videos and take the quizzes whenever they want." Students receive homework. They join online groups to exchange questions and answers about the course. The teachers hold office hours to answer questions that the students have voted to send them. They also present their own questions and observations to the students in order to help them make a deeper impression of the course. The students take a final examination to show where they rate in the class Everyone who finishes the course receives a grade and proof of completion. Top students get letters documenting their work. Mr. Thrun started Udacity, which supports free MOOCs.Udacityhopes to make a profit in the future by connecting possible employers with interested students. On his Stanford homepage he says he wants to " _ " education. "Education", he says, should be free, accessible for all, anywhere and any time Building a Computer Search Engine   _  .
is a free course that is provided on the Internet is mainly for students from American universities is offered by two scientists from the same university can be taken only by those excellent college students