The remote comes apart to see inside, and the questions are how the toilet flushes and why the sky is blue, before you have had coffee. Every book here feeds a how-does-it-work mind, and any one of them satisfies on its own. You pick the one that fits your child right now. There's a browse-anywhere answer book for a four-year-old, a hands-on machine book with tabs to pull, a girl-scientist mystery for a new reader, a volcano comic packed with real geology, and at the far end the great fat encyclopedia of how everything works. Reach for whichever matches the age and the mood.
This shelf gathers the best of the how-does-it-work canon for the budding scientist and lets you pull down whichever one fits, because a four-year-old asking why the sky is blue and an eleven-year-old who wants a cutaway of a jet engine both belong to the same obsession, just at different depths. So it runs from a lap-time answer book to David Macaulay's great illustrated bible of machines, with hands-on tabs, a girl-scientist mystery, and a geology comic in between. There's no wrong door. Match the book to the child in front of you, and when they outgrow one, the next is right there on the shelf.