How long are you in detention on big nate island?

Answer 1

As long as you want. If you want to get out, click the door. She won't stop you.

Many gum chewers do not know how to proceed, and must leave to make the stink bomb (mix yellow and blue and heat it).

Answer 2

The detention room is on the left side as you enter the school. You only get sent there if you are caught Chewing Gum in school. The detention room has a secret room under it where you will find the missing clapper for the school bell.

The Detention Room

Once you have collected all 8 of the comic pieces, and assembled them, you get gum from the guy at Klassic Komix. Go to the school and open Nate's locker using the combination from the comic strip. You will find the Blueprint to the secret room. Go to the Science room and mix a stink bomb (blue plus yellow plus heat). Now when you chew the gum, you can use the stink bomb to chase the teacher away, and go behind the file cabinet to enter the secret room.