Temperature is not a direct measure of a system's total thermal energy. The details of that relationship depend on the type of atom or molecule and the interactions among the atoms in the material. The temperature of a system is proportional to the average internal kinetic energy and potential energy per atom or molecule (whichever is the appropriate building block for the system’s material).
In science, heat is used only for this second meaning it refers to the energy transferred due to the temperature difference between two objects. The term “heat” as used in everyday language refers both to thermal energy (the motion of atoms or molecules within a substance) and the transfer of that thermal energy from one object to another. Some chemical reactions release energy, others store energy. The total number of each type of atom is conserved, and thus the mass does not change. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants. Substances react chemically in characteristic ways. Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals). Atoms form molecules that range in size from two to thousands of atoms. Substances are made from different types of atoms, which combine with one another in various ways. (List originally from the brilliant educator Heather Milo !!) DISCIPLINARY CORE IDEAS PS1.A: STRUCTURE AND PROPERTIES OF MATTER Under what conditions is this phenomenon stable? Under what conditions does it change? How does the structure of the phenomenon (or its components) relate to its function?ħ. How do energy and/or matter flow into, out of, or within the boundaries of the phenomenon?Ħ. What scale or scales account for this phenomenon and how do I describe it quantitatively?ĥ.
What is going on at the unobservable level to cause the observable features or processes?Ĥ. What are the boundaries of this phenomenon? What are its components and how do they interact?ģ. What patterns do I notice in this phenomenon?Ģ. Is there something about the material? Can Crosscutting Concept questions help us figure this out?ġ.
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