Show a large bucket of water to the children. Try to float a raw egg on top of the water and watch it sink. Allow children to discuss what they know about the ocean. Pour large amounts of salt into the bucket. Let the children feel the difference with their hands and smell the water. Place the egg back on the water and see that it now floats. Show the children a collection of seashells. Allow them to feel the differences in texture and discuss how shells end up on beaches.
For show and tell, ask children to bring in rocks that they don't mind giving to the school. Teachers may add their own rocks to the collection. Allow children to sort the rocks by size. Gather the rocks again and ask the children to sort them by texture or color. Discuss ways rocks become smooth in the environment.
Show a photograph of the Earth. Ask the children to guess what the colors represent. Give children coffee filters to paint watercolors on, then glue the dry filters to black paper. Give students white crayons to draw their own stars and a moon. Discuss common constellations and how many moons Earth has while they draw.
Incorporate weather time into each preschool class. Allow children to look out the windows and discuss the weather of the day. Discuss the current season and what kinds of weather students can expect during the season. Instruct students to recall the weather on the day before and predict the weather for the next day.