Space Balloon

With my 3.5-year-old L. we read a book about space flight. I was trying to explain to him how a rocket flies (using a picture shown in the book, with one arrow pointing from the tail of the rocket and another one pointing out toward space), but I wasn't getting anywhere. Then I remembered that we had a balloon from a friend's birthday party. So I blew it up, explained about the air coming out, what the word "experiment" means, and off it went in crazy trajectory. He was ecstatic! My 2-year-old A. noticed our activity and wanted to join in. Interestingly, L. enjoyed mostly the crazy balloon flight, whereas A. was giddy about how something big appears all of a sudden from a tiny piece of material. We ended up doing that for almost half an hour: blowing the balloon up and letting it go.