Don, are all the students new too scrolling? If so, two hours will go by in an instant! I teach scroll saw at a Woodcraft store. In those two hours you have to teach the basics first, blades, blade choice, wood, patterns, how to cut a straight line ect. The key chain pattern will be to small and difficult for most begginers. You will want basic shapes like hearts and stars.
I can help you out if you want. On my way to work, will check in this evening.