You notice some children watching the classroom’s pet hamster running in its wheel, so you join in and talk with them about how the hamster runs for exercise. this is an example of a(n) learning approach. experiential hands-on incidental intentional

This is an incidental learning approach. In this word problem "noticed" is the key word. It wasn't intentional as you did not plan to help these children until you saw what was going on. It wasn't hands on as you are not physically teaching them. It occurred by chance in connection with something else.