Have a noise pointer. Have an arrow on it, that can go in a circle, have 4 zones – white, green, amber, red. On white it is teacher time, no talking, hands up, etc. Green it is ‘partner voice’ time (which is where you can discuss and speak) at yellow it is a warning to the class it is getting too noisy and when you switch to red, hit the glass, resore order and explain why you have stopped them working and what is acceptable noise – remind them of ‘partner voices’!
Most teachers recommend a signal that students are trained to respond to. For example, a bell, timer, hand clap, chant, secret word, hand raise, etc. Something that requires a physical response in return is usually more effective.
I have one big noisy class and every time they get too loud, I add on another homework problem for the day. It’s not the best since it punishes everyone but it’s pretty effective.
Building our Classroom 
Have a noise pointer. Have an arrow on it, that can go in a circle, have 4 zones – white, green, amber, red. On white it is teacher time, no talking, hands up, etc. Green it is ‘partner voice’ time (which is where you can discuss and speak) at yellow it is a warning to the class it is getting too noisy and when you switch to red, hit the glass, resore order and explain why you have stopped them working and what is acceptable noise – remind them of ‘partner voices’!
Most teachers recommend a signal that students are trained to respond to. For example, a bell, timer, hand clap, chant, secret word, hand raise, etc. Something that requires a physical response in return is usually more effective.
I have one big noisy class and every time they get too loud, I add on another homework problem for the day. It’s not the best since it punishes everyone but it’s pretty effective.