The model for CALI s Lessonettes is even shorter, with a typical Lessonette taking students, 20-35 minutes. A good reference for gauging the length of an exercise is that each screen of text or interactive question takes students approximately 1 minutes to complete. This includes reading the material, considering answer choices, selecting a response, and reading and analyzing the feedback. Of course, this is just an estimate. The difficulty and complexity of the problem, along with the number of popups associated with a screen can alter this estimate.
Longer lessons demand that the student spend more time focused on the materials without a break.
An alternative to creating several short lessons is to create a longer lesson that can be easily divided into parts that the student can return to as time permits. This allows students to take breaks from their studying and to return to the exercise refreshed. A second benefit to smaller lessons is their buildability. You can write materials that create just in time learning nuggets that focus on a particular concept or idea in detail. Perhaps you want to create an exercise that explores a particular misunderstanding that students typically have about one theory or topic in the course.