Here are some cool science websites for you:
Joey Green's Mad Scientist Experiments - Fun stuff like an Anti-Gravity Machine, Balloon Car, Edible Glass, Fake Blood, Fried Marbles, Green Slime, Human Light Bulb, Quaker Oats Camera, Tornado Machine, Underwater Candle and more.
NASA Quest Challenges are FREE Web-based, interactive explorations designed to engage students in authentic scientific and engineering processes. The solutions relate to issues encountered daiy by NASA personnel.
From the Missourie Botanical Garden "What's it Like where You Live?" - Covers all the Biomes of the world, Freshwater ecosystems and Marine ecosystems. It also has a link to their new site on the Biology of Plants.
More great information on habitats at National Geographic.
Bird study by Cornell Lab of Ornithology.
BBC Bitesize Pages - I'm linking you to the main page. Click into any level KS1 - KS2 - KS3 (1 easiest - 3 hardest) and you will find science. These are really cool online examples of the subject matter.