[keithpeter]

Current OFSTED wisdom centres around 'checks of learning'. Plus the fact that experienced teachers can read cues including facial expressions &c (sort of like Douglas Adams and deadlines, he liked the wooshing sound they made past his ears). When you have confused 10 out of 25 students, it sort of bounces off the ceiling and hits you in the mid-forehead if you have any sensitivity.

Plus homework (error analysis is really important).

PS: 'boring' is a problem. We don't push the error bars so much (upper and lower bounds and their impact on accuracy is a GCSE Maths Higher topic). Institute of Physicists in UK did a survey in 80s of members and concluded that most studied the subject at University despite 6th form work rather than because of it!