While it is possible to get worm densities up to as much as 20 kg/m 2 or 4 lbs per square foot (Edwards, 1999), the most common densities for vermicomposting are between 5 and 10 kg/m 2 (1 to 2 lbs per ft 2).
A massive open online course (MOOC) is a model for delivering learning content online to any person who wants to take a course, with no limit on attendance. A short video about MOOCs and the connected age. Recent Spotlight.
In fact, the struggle to define MOOC illustrated above derives from the fact that we're trying to come up with an empirical definition based on the observable and/or measurable characteristics of a course (components, requirements, enrollment numbers, etc.) to see if it deserves the MOOC label or not.