In my current TA position, and I know this is common with many other TA positions, I am given a set of slides to use for the beginning presentation. It’s really hard to present someone else’s slides. For one thing, hopefully you can decode the logic/reasoning behind the order of the slides. But mainly, you need to figure out how much detail to go into on each slide. If you give too much detail you’ll either bore students or lose them. Too little and the students don’t learn enough to do their assignments.
I don’t really know how to explain how much detail I give right now. It’s more than what’s written on the slides, but less than I could give on each slide. I also try to find a way to demonstrate any new programming terminology or techniques so they can see it in practice. Then, when I’m helping the students afterwards, if a question comes up more than once, I make sure to announce the answer to the entire lab. This way I don’t end up answering it a zillion times and everyone receives the same information.
Even doing this, I can say, that for some students, my presentation is a waste of time as they already know the material. For others, the information comes too quickly and they don’t have enough time to grasp it. It’s really hard to find the right pace. Of course, it’s still early in the semester, so I hope things will improve. Including the fact, that the students aren’t required to come to the presentation. While I don’t want to encourage students not to come, I’d rather tailor the talks more for those who actually need it, and not have to worry about boring those who already get it.
In one of my TA meetings, it came out that we vary quite widely on how long we take to give presentations. For example, in one lab it took me around 50 minutes while another TA took 1 hour and 20 minutes. There are lots of things that can account for this: the amount of detail we provide, the number of questions we get asked, the speed we talk at, and the type of students in each lab. Of course, the end result is that each lab is a very different experience, and students may end up with significantly less time to work on/get help on assignments or lab exercises.