Hypnosis how-to books or starter kits for kids?

This sub seems to have a lot more of a mature focus, but I wasn't sure where else to ask. My 6 year old has suddenly become obsessed with hypnosis. She's still at the "you are getting sleeeeepy" phase, but she understands that there's science behind it and wants to learn more.

She's a very mature 6 year old and reads on a 4th grade level, so it doesn't have to be for extremely small children, but I'm having trouble finding anything online.

I'm trying to find a book, or even a silly kit with a spiral spinner and a fake pocket watch to play with for now. Preferably something a little more scientific though. Any recommendations? The YouTube rabbit hole is dodgy.