Science.8.5.E

Scientists investigate the flow and interactions of matter and energy through nutrient cycling and energy conversions such as decomposition, photosynthesis, and respiration. The states, properties, and reactions of matter can be described and predicted based on the types, interactions, and motions of atoms. Energy manifests in multiple phenomena, such as motion, light, sound, electrical and magnetic fields, and thermal energy. Energy can be modeled as either the motion of particles or as stored in force fields (electric, magnetic, gravitational) that mediate interactions between particles. The total energy in a system does not change but can be transformed or transferred between objects within the system.

Considering energy and matter inputs, outputs, and flows or transfers within a system or process is equally important for engineering. A goal in engineering design is to maximize certain types of energy output while minimizing other types and optimizing energy inputs needed to achieve the desired task. For example, engineers might develop ways to transform wind and wave energy at sea (input) into usable electricity (output) for people in coastal regions and beyond. Engineers must minimize energy loss due to heat within the device to optimize the amount of energy transformed from wind to electricity.

Matter can be understood in terms of the types of particles present and the interactions between and within them. The states (i.e., solid, liquid, gas, or plasma), properties (e.g., hardness, conductivity), and reactions (both physical and chemical) of matter can be described and predicted based on the types, interactions, and motions of the atoms within it.