I can tell you about our day trip last year. My DH and my grandfather have always wanted to go, so the day we got off the ship we went. My daughter had just turned 6. She thought the IMAX movie wsa very cool, she loved seeing the shuttles suspended above us, (SO HUGE) and going and sitting in a little lem after a short bus ride. There were quite a few parts though that I couldn't even tell you about because I knew she would be bored and they went on without she and I. Overall, she had great things to tell her class and we were glad we went, but I can say that my daughter's attention span is a tad longer than say my 7 year old nephew. I guess it all depends on the child.
I hope I helped a little, LOL. Please feel free to ask me any questions.