Science for Kids: Overnight Crystal Garden - Babble Dabble Do (uses epsom salts)
This website is FULL of experiments to do with kids - It's even got a "preschool science" section!
8 Science youtube channels for kids. Learn at home or school.
Science for Kids: Gummy Bear Science Great for inroduction of variables
More than 50 science activities for kids
Cute Cloud craft for Weather Unit!!
The water cycle: Drip the Water Drop and his adventure through water.
10 easy science and chemistry experiments for kids. Includes making slime, crystal spikes, baking soda volcanoes and mentos/diet coke explosions
This is an incredible 6 minute You Tube video about Emperor Penguins. It is amazing to watch. This would be perfect for a classroom that studies penguins and has an interactive whiteboard.
Sciencebob - an incredible site for elementary science resources, experiments, activities.