Is your principal a former science teacher? If not, then tell them to sit back and watch! If they are - then tell them to sit back and watch!
I spent many years doing cookbook labs and being frustrated that students had no clue what they were supposed to be learning, did not understand their data and were constantly worried if they got the 'right' answers! This was particularly noticeable if the labs had pre-made tables to fill in, a couple of calculations and a few questions at the end.
One of the simplest ways to convert a cookbook lab into at least an introduction to inquiry is to cut off your pre-lab handout after the Materials section! So, there's an introduction, a purpose and a list of materials they can use but the students have to figure out the rest. How they will perform the experiment, what they will measure, what variables they will use and which will need to be kept constant, how they will record and present the data is all up to them! With the scaffold at the beginning and a list of materials there is less 'mayhem' but the students are still thinking, analyzing, predicting, etc. Instead of fill-in-the-blank tables and questions they will need to make sense of their data, explain their results and determine the best way to communicate that.
Later on you may take the next step by having the students investigate questions they, themselves, have about a phenomenon or topic you're teaching and creating their own labs from the start. Now you're at a full-blown inquiry.
Hope this helps!