The very best chemistry experiment book for kids is the legendary and long-out-of-print book, the Golden Book of Chemistry Experiments. Published in 1960 during the heyday of home chemistry, it was meant to accompany the millions of chemistry kits that were sold each year to typical American kids. You got real experiments with real chemicals. Not like the so-called chemistry sets today which boldly (and insanely) advertise they contain "No Chemicals!"
