Start Up Science by Godfrey Hall - Books 2, 3, and 4. Brand new condition, not written in. Designed for 7 to 9 year olds but I think slightly younger homeschoolers could use this as well with a little supervision, and 9 year olds might find it a bit babyish. I would say more like 5 to 8?? But that's just my estimation, your child may vary.
"The Start Up Science series opens t he door to the challenging world of scientific discovery. Four books, each with 29 exercises, are filled with stimulating facts and interesting activities. From topics relating to their everyday lives like how to care for pets, to distant and exciting things, like satellites and dinosaurs, Start Up Science books introduce young readers to a wide range of subjects."
Please note I only have three books of the four book set, however each book is basically a stand-alone and can be used regardless of whether you have used any of the other ones. $10. includes standard shipping.