And there's the secret: classroom noise needs to be regulated to different levels for different learning activities.

There are four levels of productive noise teachers can use in the classroom:

Level 1: Complete silence on the part of the students

It's important that every time the teacher needs to talk to the class that all students listen in silence.This might be to introduce or review or discuss the learning concepts in that lesson, or it may to be give instructions to students. Either way, this type of class activity requires absolute silence. Being able to get students to comply is no easy task: like all other aspects of classroom management it depends on routines that are consistent and persistent.

* Level 2: Whisper.

This is when students work in pairs or small groups but the main point of the activity is not really to share open discussion - it's about giving students the opportunity to research or think very quietly together - it's a way of allowing students to make a little classroom noise while maintaining the status of quiet reflection and concentration on what is essentially a silent task.

* Level 3: Partner voice

This noise level is appropriate for much of what happens in effective classrooms. Students use this to talk to another student about the learning.This sharing of ideas and exploring concepts is a vital part of effective learning and teachers need to encourage students to talk productively in this way in class. A rule of thumb is that the teacher should be aware that one student is talking to another but should not really be able to hear every word that is being said.

* Level 4: Table voice or group voice.

This level of classroom noise is appropriate when students need to share ideas as a group and by definition will be a little louder than any of the other levels of classroom noise

What's the best way to achieve the right balance between classroom noise levels?

1. Plan the learning activites carefully so that all four noise levels can be used in all lessons.

2. Explain clearly to students why different levels of noise are needed in class for effective learning.

3. Model and practise the routines with students. Many students are not used to being silent for several minutes at a time and will need to practise how to do it. Most students will also need to be trained in how to talk about the learning focus rather than see the 'partner voice' as an excuse just to engage in social chat.

4. Cut students some slack some of the time. Human beings are programmed to communicate and talking is a natural activity, especially among young people. It's unrealistic to expect that some social chat will not go on among students as they talk to each other. Most adults find themselves engaging in social chat some of the time when they're at work, and it often makes work a more pleasant experience. The same is true for school students - the secret is to train students so that they know when a little social chat is acceptable - and they must accept that if social chat gets in the way of the learning that needs to happen in the lesson the teacher will stop the social chat.

Bottom line: Teachers need to be clear about the role of noise in the classroom. They must be consistent and persistent - they need to practise routines for using appropriate levels of classroom noise. Often a visual signal of the noise level required helps in class. Some teachers make a wall chart to remind students of what's expected. This might be a set of traffic lights or a set of 'noise control buttons' or something similar. This visual signal makes it very easy for teachers to remind students of the level of classroom noise that's expected at any given time.