How to deal with a student who is curious to the point of disrupting the class?

It sounds like you're describing a short-term situation (new-employee orientation?) rather than an ongoing one like a semester-long college course. I took a similarly-structured class a few years ago and saw the instructor handle a student like that very well.

The setting was a seminar that met for a couple hours every day for a week. The instructor had distributed a syllabus for the week, and then at the beginning of each session gave an overview of what we were going to cover on that specific day. This established scope -- we have two hours to cover X, Y, and Z. Here are examples of how the instructor handled different types of questions/interruptions:

• For things that would be addressed later in this session: "that's a good question, which we'll get to in about 15 minutes". This tells the student there will be an answer but doesn't slow things down.

• For things that would be addressed later in the week: "we're going to cover that in depth on Thursday, but (one-sentence summary of the answer)". This gives the student something, because holding your question for days can be frustrating, and like the previous one tells the student when to expect more detail.

• For things that are relevant and not on the syllabus: first try the short answer, which might be enough. If the student presses for more detail or has followup questions: "I'll need to spend more time to give you a proper answer and I want to make sure we cover everything on today's agenda, but I'll be happy to discuss it with you {after class, over lunch, etc}". This shows the asker and the other students that you respect everybody's time (we're not going to bog down on this right now) and also that you're happy to help in a different setting. Alternate approach: "We don't have time to get into that now, but {some accessible source} covers that in a lot of detail." You can use this when you think the asker can do his own research if you point him in the right direction.

• For things that aren't relevant: "I'd like to keep us focused on {current topic}, so let's not get into that now". If the student really cares he'll follow up outside of class and you can decide how to handle it then, but often it seems this is enough to convince the person that it wasn't that important (or that he should figure it out on his own).

Because you are teaching coworkers rather than students who'll be gone in a week, you might want to plan for some free-form discussions either during or after the class -- for example, unstructured lunches with the students during the class (when anybody can talk about anything), or periodic deeper-dive sessions on aspects of whatever it is your group does. I once worked at a company where the chief software architect gave a casual weekly talk (with plenty of Q&A) on whatever part of the software he thought people should know more about.

A final thought: at several companies I've seen good results from assigning mentors to new employees. This isn't just for early-career people or recent graduates; even experienced people need to learn the ropes of your organization, product, process quirks, etc. The mentor acts as a way to channel most of Bob's questions to that one person, which provides relief for everybody else (like you). Of course, it has to be organizationally ok for the mentor to spend time providing that guidance -- the mentor won't get quite as much of his own work done during the new person's ramp-up time, but if the mentoring provides a net benefit to the organization it's worth it.