I would be interested in finding out how wide-spread the use of open labs is. A few of you have asked for info on the open lab format. A few years ago, our college was faced with the problem of serving a growing student population with limited lab space, so two of the faculty members developed an open schedule lab format that has been very successful for us. Students check in and out, so we have a record of their attendance. Materials are available to them from stations around the room, and the students can usually take the materials back to the desk for use.
Faculty serve as lab instructors, answering questions and interacting with the students.
In recent years, we have adapted most of our labs to make them investigative in nature. There are obvious pros and cons to this format. Students who need extra time in lab can have it, for example, and the number of hours faculty spend in the lab can be varied according to other aspects of their load. The primary con is that faculty members no longer have full control over the experience their students have in lab. We faculty do not always agree on everything, and we do not always know whether a student got the kind of help we would have provided.