Both Asynchronous and Synchronous are proven effective methods of on-line teaching. Synchronous classes require teachers and students to be on-line at a specific time. All lectures, discussions, presentations, and interactions occur during the specific time slot. Asynchronous classes do not require teachers and students to be on-line at the same time. The teacher will post learning assignments, lectures, and presentations to the on-line site and students can access and complete the work on their own time table. Teachers will set a time limit, usually one week, for students to complete assignments.