The "Education" in Scientific American has a lot of experiments that people can do at home with simple materials. The link I share is the science behind a magic show I've seen before. After the practice, they have some questions like "What is the slowest you can pull the loop away and still have the coin fall into the container? What happens when you use a bigger or smaller paper loop?"
I remember when mentioned how Bacteria works in past lectures. There is a recent research about that. Bacteria swap genes with their neighbors more frequently than researchers have realized.