Every once in awhile things just make you smile. A friend of mine posted a download to The Golden Book of Chemistry. Why is this so funny you ask? Well, apparently this book was banned because the experiments could be dangerous. But, my understanding is that you can download it now for free (remember I am not a lawyer nor do I play one on TV).
So use your best judgement on whether or not you should allow your children to read it. It has some excellent explanations on chemistry. I felt more informed reading it.