Is it a title 1 school?

Some classrooms have teacher workrooms with glass windows at one end. Some schools I have been in have preferred plain observations to be through the workroom window. You can't hear every little sentence (depends on the volume of the speaker) but you get the general idea and can usually see what is on the board/smart board and how the interactions are working. Usually the kids forget you are there if they notice you or never know you are there.

...reading is pleasure, not just something teachers make you do in school.~B. Cleary