In the first scene it talks about what you should not do in class and in the second scene it tells us what we are suppose to do. In the first scene people are unprepared, loud, sleeping and cover the isle with there stuff. In the second scene people are listening, already prepared, raise there hands when they have a question and is carefuly listening.
In the third and fourth they are in the lab and the third it is don'ts and in the fourth scene it is the rights. in the third scene people are playing with the liquids, throwing beakers, spilling liquids, not being careful and injuring others. While in the fourth scene everyone is not touching anything and is waiting for instruction