Home Science Tools (formerly known as Home Training Tools), operated by a Christian homeschooling family, sells just about anything you could want for science including curriculum, chemicals, lab equipment, activity books, science kits, resource and activity books, videos, dissection specimens, microscopes, telescopes, and creation science resources.
They have an excellent website and also publish a catalog. Their exceptionally helpful catalog is arranged topically, with very useful "Quick Tips" such as "Making Microscope Slides" interspersed with product descriptions and illustrations. To make it even easier, their "Quick Selection Guide" lists topics and all possible resources in index fashion showing catalog page numbers and recommended age group. Their website has much of the same information, nicely arranged and easy to find.
Another major offering of Home Science Tools is science kits to accompany science courses from a number of major publishers: BJUP, Alpha Omega (LIFEPACs/Switched-On Schoolhouse), A Beka, Apologia, Castle Heights, and Christian Light.