What are four steps scientific investigations often follow?

Answer 1

State the problem (hypothesis)
set up an experiment
collect data
make conclusion based on the data

then maybe refine and re do it

Answer 2

So, let us review the steps. First, connect the gas supply. If you don't do that first you don't get a flame... Second, close the air hole. This is very important and yet usually overlooked. If you don't close the air hole striking back may occur, and that's very hazardous. Third, turn on the gas tap, and at the same time put a lit match or a lighter flame above the top of the Bunsen burner. If you put the flame on top of the Bunsen burner first you run the risk of well, misjudging the position and burning you fingers off, while it you do that after you turn on the gas you risk suffocating everyone in the room with gas.