Rates of change vary. Children can be asked to observe changes in the position and apparent shape of the moon. Parents and children can track the position of the moon at the same time each night and draw pictures of the moon's changing shape to learn that change takes place during the lunar cycle. Children can also observe and describe changes in the properties of water when it boils, melts, evaporates, freezes, or condenses. Structure and function.
Children can learn that skunks let off a bad odor to protect themselves.
Children also can learn to infer what a mammal eats by studying its teeth, or what a bird eats by studying the structure of its beak. To understand the concept of organic evolution and the statistical nature of the world, students first need to understand that all organisms and objects have distinctive properties. In most of the natural world, however, the properties of organisms and objects vary continuously. Young children can learn about this concept by observing and arranging color tones. Older children can investigate the properties of a butterfly during its life cycle to discover qualities that stay the same as well as those that change.