STEM fun for smart tots Meet Mia, Ava, Oli, and Seb: they're the four engaging characters created by Harriet Blackford to introduce very young children to STEM concepts. This simple story, enhanced by Mike Henson's humorous illustrations and fun-to-do experiments, makes a fascinating subject come alive for preschoolers. If the earth is round, why don't we all just fall off and float away? The answer is gravity, and budding...