Let's face it, kids learn more by using more of their senses anyways. My children learned a lot more from doing experiments and touching science related materials than they learned from a book. Textbooks can be dry and boring, but working with actual objects can really spark an interest in science. The great scientists became interested in science because they liked to experiment. Once they saw what happened, THEN they started reading and searching textbooks for why their experiments worked or didn't work.
I've written a post with a bunch of ideas of what kind of kits are available, how to use some things you have at home, and my favorite resources for science instruction. Some people have done the hard work for us and put their resources into a book, online experiment site, or pdf file. I hope you get some great ideas for science from these resources!
Home School Science Kit