Pop! The Invention of Bubble Gum by Meghan McCarthy is a level 740L on the Lexile reading level scale. Pop! The Invention of Bubble Gum is about not only the invention of gum because that has been around for centuries, but the invention of the best gum ever, bubble gum. It all started with an accountant at Fleer Gum and Candy started to mess around with different recipes. Students will be so engaged by this book, and maybe you can use this in science to learn how bubble gum is made. If it's not too complicated, maybe you could create some bubble gum in class.