You pick up a missing comic piece and create a stink bomb. (see related question)
The Bunsen burner is in Big Nate Island in the school building in the science lab.
make it your self by mixing blue and yellow until its green in the science lab
yea its in the science lab then hop on a skeleton and you'll see it
you use the smoke bomb from the science lab and use it in the detencion room.
The piece is on top of the "solar system" display at the far left.
go to the science lab in the school. click on the beaker. then mix all colors.
mix yellow red and a lot of green and yellow
You go inside there is one in the end of the science lab and one on the broken intercom
By mixing the blue, red, and yellow chemicals together in the science lab which is inside the school.
You set off the stink bomb you made in the Science Lab she says "what is that terrible smell!" then you can get out of detention.
go to the left jump and look at the solar system model and there's a comic in it.
To get out of detention on Big Nate Island on Poptropica, use the stink bomb that you make in the science lab to drive the teacher out of the room.