Feynman lectures on physics. A three tome collection of an amazing full year course on physics that Feynman tauch to undergraduates. I think you can find the videos of the lectures online somewhere. These three books cover machanics, fluid mechanics, electricity, magnetism, waves, quantum phenomena, optics, sound, material science. Math is explained as necessary for each new topic. The torrents might have them as
PDF. If print them to paper, you will not be wasting that ink. If your child shows some interest in physics, you should definitely print them on your office printer. 800+ pages.