• Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles or energy stored in fields. (HS-PS3-2)

• Energy is a quantitative property of a system that depends on the motion and interactions of matter and radiation within that system. That there is a single quantity called energy is due to the fact that a system's total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms. (9-12)
• At the macroscopic scale, energy manifests itself in multiple ways, such as in motion, sound, light, and thermal energy. (9-12)

• Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system. (9-12)
• Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems. (9-12)
• The availability of energy limits what can occur in any system. (9-12)

• Although energy cannot be destroyed, it can be converted to less useful forms—for example, to thermal energy in the surrounding environment. (9-12)

• Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models. (9-12)
• Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales. (9-12)

• The transfer of energy can be tracked as energy flows through a designed or natural system. (6-8)
• Energy may take different forms (e.g. energy in fields, thermal energy, energy of motion). (6-8)
• 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. (9-12)
• Energy cannot be created or destroyed—it only moves between one place and another place, between objects and/or fields, or between systems. (9-12)

• Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. (9-12)
  • Use a model based on evidence to illustrate the relationships between systems or between components of a system. (9-12)

• Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. (9-12)

• 6-8: 4D/M3ab. Atoms and molecules are perpetually in motion. Increased temperature means greater average energy of motion, so most substances expand when heated.
• 6-8: 4D/M3cd. In solids, the atoms or molecules are closely locked in position and can only vibrate. In liquids, they have higher energy, are more loosely connected, and can slide past one another; some molecules may get enough energy to escape into a gas. In gases, the atoms or molecules have still more energy and are free of one another except during occasional collisions.

• 3-5: 4E/E2a. When warmer things are put with cooler ones, the warmer things get cooler and the cooler things get warmer until they all are the same temperature.
• 3-5: 4E/E2b. When warmer things are put with cooler ones, heat is transferred from the warmer ones to the cooler ones.
• 6-8: 4E/M1. Whenever energy appears in one place, it must have disappeared from another. Whenever energy is lost from somewhere, it must have gone somewhere else. Sometimes when energy appears to be lost, it actually has been transferred to a system that is so large that the effect of the transferred energy is imperceptible.
• 6-8: 4E/M2. Energy can be transferred from one system to another (or from a system to its environment) in different ways: 1) thermally, when a warmer object is in contact with a cooler one; 2) mechanically, when two objects push or pull on each other over a distance; 3) electrically, when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device; or 4) by electromagnetic waves.
• 6-8: 4E/M4. Energy appears in different forms and can be transformed within a system. Motion energy is associated with the speed of an object. Thermal energy is associated with the temperature of an object. Gravitational energy is associated with the height of an object above a reference point. Elastic energy is associated with the stretching or compressing of an elastic object. Chemical energy is associated with the composition of a substance. Electrical energy is associated with an electric current in a circuit. Light energy is associated with the frequency of electromagnetic waves.
• 6-8: 4E/M6. Light and other electromagnetic waves can warm objects. How much an object's temperature increases depends on how intense the light striking its surface is, how long the light shines on the object, and how much of the light is absorbed.

• 3-5: 11B/E4. Models are very useful for communicating ideas about objects, events, and processes. When using a model to communicate about something, it is important to keep in mind how it is different from the thing being modeled.
• 6-8: 11B/M4. Simulations are often useful in modeling events and processes.

• 5-8: Motion & Forces
• 9-12: Motions & Forces
• 9-12: Conservation of Energy & Increase in Disorder

This simple, yet thought-provoking simulation helps students to "see" the flow of energy through a real-life system -- from start to finish. They can choose sunlight, steam, flowing water, or mechanical energy to power their systems. Very effective way to visualize energy transformation and a great way to introduce the Law of Conservation of Energy.

• Physical Sciences K-8 Energy Transformation Unit
• Physics First Energy Transformation Unit

This simple, yet thought-provoking simulation helps students to "see" the flow of energy through a real-life system -- from start to finish. They can choose sunlight, steam, flowing water, or mechanical energy to power their systems. Very effective way to visualize energy transformation and a great way to introduce the Law of Conservation of Energy.

• Physical Sciences K-8 Teaching Energy in the Elementary Grades Unit
• Physics First Teaching Energy in the Elementary Grades Unit