I make sure that all students know what they need to bring in for their investigation and what their first step will be. The third stage is the investigation itself. Here the students are pretty much on their own. I am always amazed at how little they need or want my guidance. Watching how involved students become in their inquiries is for me the greatest evidence of the value of scientific inquiry in the classroom.
Classroom management is handled because students are interested in what they are doing.
They feel empowered at being allowed to make their own choices. I do circulate amongst them as they work but mostly to ask them questions about what they are noticing and to take part in their discoveries. It is very important to allow students as much time as they need to complete their inquiries. I always make sure I have something for them to do if they finish early. More often than not they begin working on analyzing their results.