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 scientists can find out how it works and why it's so important.