Jefferson County Schools--Science Online--Lesson Plans, Interactive Activities, Worksheets, and Links for grades K-8 The absolute best that I have seen and used in science--check it out!!
Jefferson County Schools--Science Fair Site--good tips!!
ScienceNetLinks--lessons, tools, resources, benchmarks
Globio--Glossopedia is a free, interactive, online science encyclopedia for elementary-school science and general studies applications, comprised of a series of interlinked, informative multimedia articles written for children ages 8–12. Articles contain text, video clips, audio files (vocabulary pronunciation, recorded animal sounds.), photo galleries, maps, interactive features, and content-related subject lessons.
Science Powerpoints--for all grades K-12--prepared and ready to go by Jefferson County Schools!
BBC Website from the UK--excellent interactive science activities in all areas
Entomology for Beginners--all sorts of good things for insects, metamorphosis, insect classification, etc.
ScienceMaster--Notice the Jumpstart Science, Learning Galleries, and Quick Facts icons--be sure to explore!
BackyardNature--plants, animals, fungi, ecology, geology, gardening, naming and classifying
Enchanted Learning--illustrated scientific dictionaries
Botanical Online--Botanical glossary, healthy food, medicinal plants, poisonous plants, educational activities, etc.
PBS Science--Interactive activities, links for educators and kids
Science for the Classroom by PBS--Standards-based resources you can search by grade level and topic
Kathi Mitchell's Science Links for Kids and Teachers--lots of science links and activities
Schools Online from University of Illinois--Interactive activities like The Great Plant Escape, Where Your Food Comes From, Riding the Winds--a Weather Adventure and more--AWESOME site
Quia Science Tests and Resources--Grades 4 and 5 all different types of science topics
Biology4kids.com--cells, microorganisms, plants, invertebrates, vertebrates, and animal systems
Discovery Education's Curriculum Center--bacteria, oceans, chemistry, solar system, electricity, the universe, genetics, weather and climate, magnetism, and viruses
Softschool.com--free science games and activites, worksheets, quizzes, etc.