Our school went to a modified block last year, and I am very happy with
it. Mon, Tue, and Friday are 8-period days, 46 minutes each. Wed and
Thu are block days, four periods/day, 91 minutes/period. Wed is periods
1, 3, 5, 7; Thu is 2, 4, 6, 8. This arrangement prevents burnout with
constant 90-minute periods while at the same time allowing a longer
period once a week for either a complete lab or in-depth testing.

I teach AP Physics C. For first semester I am allocated one period of
the eight, and I completed through Collision & Momentum. For second
semester, I am allocated two periods of the eight, and will finish
mechanics and use the double-up time to do E & M. This is the first
year for this double period arrangement, and I am doing it in concert
with the AP Calc teacher. Her AP Calc B/C meets two periods of the
eight first semester and one period of the eight second. So her double
period is opposite mine and her students and mine balance the double
periods easily.

We have the best scheduling system on the planet, but it takes a lot of
resources to implement. We have a six-day cycle (A - F). Each day
runs from 7:30 to 3:30, broken up into 32 15-minute "mods". Within
reasonable limits, teachers are free to set the meeting parameters of
their classes as they wish, and the master schedule is re-generated
every year based on their choices and student enrollment.

I teach AP Physics B (120 students) with another colleague and AP
Physics C (25 students) by myself. For the B course, each student
meets four times per cycle. Two of those are 4-mod periods (1 hour) in
a lecture hall with 60 kids. The other two are 8-mod (2 hour) periods
in the lab with, on average, 20 kids. My colleague and I are both
scheduled for the lecture section, which I teach, and each of us has 3
of the lab sections.

The C course meets more conventionally; 5 times per cycle for 4 mods
each. If you like, you can look at my schedule at: