I used to do demos for the local cub scouts day camp. This camp was set up with 1 hour activities for 7 groups of 10 to 15 scouts each. The groups would rotate from station to station for a one hour session. For each of my sessions, I would make something that the troop could use for camping and that I could easily make in each session along with the lecture. Usually something like a tripod set with a couple of S hooks, or some cooking utensils, fire starters, etc. As these were younger kids, my sessions were just demo and lecture, but the kids were always very interested. They were usually fascinated by the fire and the plasticity of the hot steel.
I always gave whatever I made to the troop leaders, NEVER to one of the kids. I learned that the hard way when I gave a fire starter to one of the kids after I finished it. I had 14 others demanding one also .