Tracking energy and matter flows, into, out of, and within systems helps one understand their system’s behavior.
Primary (K-2)
Objects may break into smaller pieces and be put together into larger pieces, or change shapes.
Elementary (3-5)
Energy can be transferred in various ways and between objects.
Matter is made of particles.
Matter flows and cycles can be tracked in terms of the weight of the substances before and after a process occurs. The total weight of the substances does not change. This is what is meant by conservation of matter. Matter is transported into, out of, and within systems.
Middle (6-8)
Matter is conserved because atoms are conserved in physical and chemical processes.
Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion).
Within a natural system, the transfer of energy drives the motion and/or cycling of matter.
The transfer of energy can be tracked as energy flows through a natural system.
High (9-12)
In nuclear processes, atoms are not conserved, but the total number of protons plus neutrons is conserved.
The total amount of energy and matter in closed systems is conserved.
Changes of energy and matter in a system can be described in terms of energy and matter flows into, out of, and within that system.
Energy cannot be created or destroyed—it only moves between one place and another place, between objects and/or fields, or between systems.
Energy drives the cycling of matter within and between systems.
Energy and Matter are essential concepts in all disciplines of science and engineering, often in connection with systems. “The supply of energy and of each needed chemical element restricts a system’s operation—for example, without inputs of energy (sunlight)
and matter (carbon dioxide and water), a plant cannot grow. Hence, it is very informative to track the transfers of matter and energy within, into, or out of any system under study.
“In many systems there also are cycles of various types. In some cases, the most readily observable cycling may be of matter—for example, water going back and forth between Earth’s atmosphere and its surface and subsurface reservoirs. Any such cycle of
matter also involves associated energy transfers at each stage, so to fully understand the water cycle, one must model not only how water moves between parts of the system but also the energy transfer mechanisms that are critical for that motion.
“Consideration of energy and matter inputs, outputs, and flows or transfers within a system or process are equally important for engineering. A major goal in design is to maximize certain types of energy output while minimizing others, in order to minimize
the energy inputs needed to achieve a desired task.”
