1 Consider location. Place the science center near a sink so filling the water tub and aquarium is simple. Spilled sand and water can be easily cleaned up on a tile flood and light from a window encourages plants to grow Define areas for various experiments by finding low-traffic areas for messy activities (cooking, planting) and active projects (magnets, machines). You may want to provide a quiet spot where children can concentrate on sorting and classifying and a protected area for storing in-progress projects.

2 Start simply Offer children only a few materials at first. Then add duplicates of popular items (magnets, magnifiers). To add challenge and keep interest, change and rotate materials.

3 Acreage for different group sizes. A long table or big floor space encourages group projects such as creating a mural of the seashore. A box lid containing leaves with a magnifier nearby inspires individual observation.

4 Make investigations easy for the children - and for you. Use a plastic dishpan to store drippy water toys, clear boxes on open shelves to show off sorting materials, and trays to display (and carry) collections of simple tools. Organize interest centers by establishing comfortable, low places for observation and involvement in ongoing activities such as caring for animals or raising plants. Put materials related to these activities (water containers, newspapers) close by on shelves.

5 Keep reference materials nearby. Place children's science magazines and books on a low rack with their intriguing covers facing out. You can add attractive wall posters of dinosaurs or baby animals. A computer allows children to search for visual information and related sounds (such as barking sea lions).

6 Furnish documentation materials. For written impressions, provide an accordion file of assorted paper and a bucket of markers. Children can use yarn, pails, and plates to create graphs, and a tape recorder enables them to describe investigations.

7 Create a science-display area. Use a bulletin board or the back of shelving to share children's scientific drawings. Display hands-on models or children's projects at eye level on top of cabinets.

8 Keep safety in mind. When appropriate, introduce or demonstrate materials. Arrange for "crowd control" (sign-up sheets, colored entry tags, specific number of chairs at a table) for exciting activities. Daily, check for broken equipment (chips on prisms, cracked sand toys). Keep sharp items (knives, scissors) out of children's reach and store items that require adult supervision (electric fry pan, blender) in cabinets.