I have the 2nd ed. in electronic form and later acquired the 1st ed. in paperback. I was really hoping to be able to use the book but I noticed a difference in some of the lesson names on the flow chart. Is there a significant difference between the two editions? (Of note my son is 9 and we are moving fairly quickly through volume 1 because he already understands quite a lot that is covered… so far.)
The first and second editions of BFSU Volume I are very much the same. The first edition will work perfectly well in giving your kids a solid background in beginning science. The second edition is only somewhat adjusted to make it more in tune with the Next Generation Science Standards (NGSS), which may or may not be of any concern depending on the state you live in. In this regard, the second edition of Volume I, contains two additional lessons: C-3A Energy and Force, and B-5A Adaptations and survival. Thanks for your question.