S.T.E.M. Principles Your Child Will Learn Through Play: OPTICS FIELD OF VISION MIRRORS AND REFLECTION LIGHT D.I.Y. Time: 70 min | Play Time: Unlimited Manufacturered by Smartivity. This S.T.E.M. Educational D.I.Y. Toy includes 1 richly illustrated easy-to-understand step-by-step Instruction Booklet 1 Learner's Log with explanation of Scientific Principles and additional activities for children to experiment with understand concepts and reinforce learning. This is a Do It Yourself Activity Kit designed to help children of ages 6-8 to understand fundamental principles of S.T.E.M. subjects (Science Technology Engineering and Mathematics).