Systems and Cycles
Systems and cycles form an important part of science. A system is the setting in which cycles occur. A cycle can invlove changes in state, such as the water cycle: liquid to solid to gas and back again. A cycle can also involve a change in life phase, such as the life cycle: birth to adulthood to reproduction, then death. Cycles can also involve changes in composition, such as the carbon cycle: such as CO2 to CH2O +O2 (organic matter) to decomposition, where carbon is broken down and released as CO2 or CH4. Systems include both a cycle and all the factors that may influence the cycle. In order to study and better understand them, systems can be represented by simple models. For an activity to practice thinking about systems and cycles, see the companion PDF.