My son starts high school on September 1. We have a bit of a late start this year, because budget cuts have reduced the school year to 175 days.
I counted only 84 days of instruction in the first semester, and 4 of those are “minimum days”, which means that each class gets 80*1.5+4*1=124 hours of instruction per course. The second semester looks like 87 instructional days, with 5 minimum days, for 128 hours of instruction, but some days may be lost to state testing (also AP testing in the higher grades). For those with fast mental arithmetic, the missing 4 days are the final exam days at the end of each semester.
My son’s high school uses an “Excel Block Schedule” in which students take only 3 (or 4) courses each semester, but get 1.5 hours a day of each course. This approach is good for science labs, theater, and art, where long blocks of contiguous time are needed for some of the activities. It also cuts down on some of the time management and executive skills problems of managing due dates for 6 or 7 classes. The high school claims that the only problem they have seen is in some math classes, and they provide a slower track in algebra for students who need it. I’m not worried about math for my son, but I think that there could be problems with retention of his Spanish, with 9-month intervals between courses.
I think the block schedule will work well for my son, who prefers being immersed in a few projects, rather than flitting from subject to subject, though I’ve heard from parents of ADD kids that it is very difficult for their kids to deal with the long class periods. There is a reasonable discussion of the advantages and disadvantages of block scheduling by Lisa Doherty.