iKnowthat.com has multimedia educational games for kids ages 2-12.

Science Lab Activities

The Science Lab has interactive illustrations and activities covering popular science topics such as gravity, volcanoes, earthquakes, sound, plant cells, animal cells, the solar system, the human body, atoms, matter, vision, optics, weather, the water cycle, food chains, food webs, and photosynthesis.

Each of these science topic has an interactive illustration with important vocabulary defined and spoken. Each science topic also has an activity that expands on the basic concepts associated with that topic. Some of these activities are simulations, while others are guided explorations.