BBC Science Clips has science simulations/games categorized by six age spans: from age 5-11.  The simulations include: Sorting, Light & Dark, Push & Pull, Solids & Liquids, Plants, and many more.

Applications for Science Teachers: Elementary teachers of science will find many age-appropriate simulations that support understanding of the Big Ideas in science. Some of the simulations could be useful for uncovering student preconceptions. Each of the simulations are set up so that you can easily copy and embed the simulations in your classroom blog/web page.