Sleep patterns change during adolescence, but unless you can alter the school day, students need to figure out ways to deal with their predilection for going to bed and waking up late. Jason at FrugalDad has a nice compilation of statistics about why we need sleep. Particularly useful is the section on different ways to get more sleep. (I also like the fact that he cites his sources at the bottom.)
Source: ᔥhttp://frugaldad.com