Choose a science topic that the children can participate with by bringing items from home for show and tell. You may wish to choose a topic related to something else you are studying.
Whatever the children's usual procedure is for sharing, add another procedure by deciding 2-3 categories on the floor graph to divide the shared materials.
As each child completes their time sharing, have them place their show-and-tell items into the appropriate column of the floor graph.
After everyone has shared, compare the sets on the floor graph. Work together to determine which set has the most and which has the least..