6. Structure and function. There is a relationship between the way things look (and feel, sound, etc.), and how they act or what they do. Your dog's teeth are different from yours because of the different types of food you eat. Plants have different parts to do different jobs (leaves for photosynthesis, flowers for reproduction, roots to collect water and nutrients). Study the differences in the structure of objects around you and try to relate them to the different functions of those objects.
7. Change. The natural world constantly changes. Some of these are quick and easy to observe (for example, the weather). Other changes take place over days or months (phases of the moon). Still others take many years (the building of mountains). Observe come of the changes in the world around you. Experiment with water freezing, melting, evaporating and boiling. Explain to your children how these changes relate to the water cycle on our planet.
8. Variation. Everything, living or nonliving, has a set of characteristics, or properties, that make it different from all other. The world is full of variations. Some of these differences are small or insignificant, like different eye or hair colors. Other differences are much more significant, like the difference between living and non-living things. There are variations between individuals within a species (for example, breeds of dogs) as well as variations in a individual as it grows and changes throughout its life (how a caterpillar changes into a butterfly). In most of the natural world, things change constantly.
9. Diversity. This is the most obvious characteristic of the natural world. Even preschoolers know that there are many types of objects and organisms. In elementary school, youngsters need to begin understanding that diversity in nature is essential for natural systems to survive. Children can explore and investigate a pond, for instance, to learn that different organisms feed on different things.