I agree that safety is the number one necessity in a school these days.
However, after that, I think to thrive students need an environment of creativity and exploration. In my opinion, students learn so much better when they can put hands on concepts and manipulate them to figure out how they work than sitting passively in a straight row of desks taking notes.
This kind of learning is messy and loud (which some administrators frown upon) but it is engaged learning which science is finding tends to make learning stick.
After that...there has to be an aura of positivity and trust between staff and students. If we respect them, it is much easier to require respect back in return.
Students and teachers must both feel safe and inspired in order to achieve great things. Safety includes physical safety as well as emotional safety--the ability to speak freely and without fear of shame or reprisal. Inspiration comes from many sources and is a driving force in achievement. Inspiration creates passion, and passion is the root of all great achievements.
You've got some good answers here. People must feel safe to attend school and to communicate their ideas (popular or not) within the school. Students should be secure in the environment to be who they are (or who they think they are at the time). If they are white, black, Asian, Hispanic, straight, gay, Republican, Democrat, whatever...they should feel safe enough to convey this identity without fear of recourse.
If they don't, true learning can not take place, and respect for one another's diversity can not be fostered.
A former principal of mine summed it up by saying "Relationships come first. Curriculum comes second, after the relationships are established." Unfortunately, educators are being asked to do more and more to counteract influences outside the school environment that get in the way of students being ready and able to learn. Previous posts have touched on many of the pieces - physically safe environment, emotionally supportive people, intellectually stimulating and inviting. For some students, schools also need to provide food, clothing, and other basic needs that have to be fulfilled before a student can focus on anything other than survival.
With so many children coming from broken and dysfunctional homes, there needs to be a secure and stable environment for students. This means that the teacher must be a parental figure in a sense, providing the necessary discipline and psychological comfort to students that an adult in charge can.
Another important aspect to the scholastic environment is that of a competitive atmosphere. Studies have shown that average or below average students overachieve when they are surrounded by a healthy spirit of competition. On the other hand, bright students and average students who are in a non-competitive environment underachieve. Even a competitive sports program has an affect upon the academic achievements of students.
Referring specifically to the inside of a classroom, the space should be large enough to properly accommodate the students; reflect the personality of both the teacher and students (with posters, art, work examples exhibited, etc.); have proper computer technology for use; and, hopefully, be a place where kids are happy to spend an hour each day. Being an English teacher, I always try to provide a small library for students to use, and I like to occasionally play background music for days when students are working for long periods on their own.
I agree that physical safety is the first function of school environment; however one could do that by placing bars on the windows and having the halls patrolled by armed guards. As well as safety, it must be inviting, positive and encourage students to pursue their studies. Rules, etc. should be phrased in positive terms. Students should be encouraged to take chances on academic matters, even at the risk of being wrong; as no one learns from being right all the time. Teachers should be facilitators, display a welcoming attitude and nurturing disposition; such that students feel that they are important. All too often, this is not the case.
First, a school needs an environment in which students feel physically safe. Students can never learn if they fear that they might be bullied or beaten up.
Second, once a school is physically safe, it must also create an environment that is intellectually safe. Students must feel that it is okay for them to take chances academically and to risk being wrong. They must feel that they are supported in their efforts to learn. They must have an environment in which they are able to concentrate on their studies.
If a school is safe in these two ways, it will have a chance to be an effective school.