6 hours a day is not enough sleep for most normal men and most women need more than 7 hours. The learning of coordinated physical tasks is particularly impaired by sleep loss, Interventional Radiolgists in-training, take note. Teenagers sleep at different times from adults. Their hormonal background often means that they are awake later than normal adults. This need not be a problem, provided that total hours sleeping are at least 8 hours and, ideally, more than 8 hours a day.
Students often confuse metaphor for the underlying truth that it is supposed to represent.
Most good teachers will, at some stage, make a compromise to obtain brevity and clarity, when trying to elucidate a particular point. The purpose of metaphor and simplification is to provide a skeleton of thinking upon which the neophyte may add the flesh of the greater body of information on the subject being taught. The teacher is always divided from the pupil by the teacher's experience. A fairly good example of this is given by the plethora of books explaining software. It is very rare for the writer of a particular piece of software to be capable of writing a decent and understandable manual.