It also means that the teacher can spend more time with individuals making sure that each student has a complete understanding of the subject matter at hand. For science classes these longer class times are almost a necessity. Labs can be setup and completed in almost a single class. Longer classes also mean that teachers are able to give more comprehensive tests. By doing this, students are better prepared for the much longer semester and final exams.
Teachers also benefit from block scheduling.
They are given more time to plan for lessons, making them better and more extensive. They are able to cover more material and teach with different styles when given this much time as well. Another positive thing about block scheduling is that the negatives to block scheduling are few and far between. Some people think that when given 2 days to do homework you will get 2 days worth of work. But as a student who has experienced this firsthand, I can tell you that I receive no more work now than I did before.