The activity I would do with a class is The Sun and Shadows, as we are located in the southeast and we have some nice sunny days! I like the idea of teaching about Ultra Violet light and the benefits and harm it can do. It is a nice hands on activity based learning where the children can imagine and improvise. I would teach the shadows by discussing what the children know about shadows and I would preferably bring them outside with chalk, and in pairs to draw their shadows, and to have them discuss and observe differences in their shadows depending on where they were standing and where the sun is. I would bring them out later in the day to stand in the same place, draw their shadow again, discuss differences and why this happens. It would be a lovely activity to make the bear/fish/landscape and have children explore with flashlights.