Teacher's Role in Classroom Management

Curious about how a teacher handles her class, I came to observe a Physics class of roughly 40 students; a mixture of two sections in third year. The classroom set up is so high school. When I looked up at the ceiling I saw Chinese lanterns hang loosely; more of it filled up the square ceiling. The walls are pinned of colorful cartolinas painted with maxims from famous world philosophers. It’s funny that I found mobile numbers scribbled on them which I suspected written by the students wanting to have textmates. The walls at the back of the room are filled up of huge pictures of Philippine Presidents with their names in bold characters; the ones you get to see on a daily basis and will make you memorize them unconsciously.
The class started with the checking of the students’ attendance, after which, the teacher recalls the last meeting’s topic. Then the students took hold of their assignments while the teacher wrote the problems on the board about finding velocity. To my calculation, only one third of the students in the classroom seem to be paying close attention. Some students had their time poking their seatmates, some really enjoyed throwing crumpled papers upon their classmates and few went in and out of the classroom without even noticing my presence at the back.
Apparently, the teacher has established a very low affective filter in the classroom. The students barely showed respect or fear to the teacher. The teacher’s voice seemed to be drowning in the noise created by the blabbing students. I can share empathy to her as a teacher dealing with a huge number of students in a classroom. I understand that having more than 40students in your class is pretty hard to manage. So her attention is focused alone on the students who actively participate in the discussion. The students are pretty hard to get their attention and have them participate in a lesson.
There should be some necessary things to be re-considered. The classroom set up is inappropriate. The teacher remains positioned in front overlooking some students at the back. There should be a particular seating assignment so the students will not have the freedom to choose any seat that they feel comfortable watching the playground. The teacher should not maintain a low voice throughout the discussion because it shows small passion to teach. The teacher might introduce an exciting strategy in presenting her lesson. I have observed that the students are lively and joyful in playing around the classroom during the class. Perhaps they might enjoy a game in the classroom as facilitated by the teacher. The teacher can start the lesson with a little competition that might entice the students to participate. A plain discussion seems to be boring for them but group work and each assigned a specific activity might pull them together to work on their own. I believe in this scenario that teaching doesn’t mean the teacher has always to do the talking. Rather as a teacher, she can facilitate the class to discover things on their own.