The school day normally has six teaching periods, each of 45 minutes; the first class starts at 8.35 a.m., after Chapel and the Tutor period, and the last afternoon class finishes at 3.15 p.m. Between those periods are either significant breaks or an interval of 5 minutes to allow boys ample time to move from one classroom to another while also clearing their minds in readiness for the next lesson. The timetable ensures that all boys are engaged in a class for all periods, and in many cases all the boys of a Grade are taking lessons in the same subject at the same time – this makes it easy when a boy needs to change set. The timetable operates on a ten-day (i.e. two-week) cycle.