PS2+(9-11)+-+5


 * Students demonstrate an understanding of energy by… **

__5a describing or diagramming the changes in energy (transformation) that occur in different systems (eg. chemical = exo and endo thermic reactions, biological = food webs, physical = phase changes).__

 __5b explaining the Law of Conservation of Energy as it relates to the efficiency (loss of heat) of a system.__

What do these GSEs mean? What subtopics do students need to address to understand these GSEs?

 * Atomic Theory
 * Basics of Chemical Reactions
 * Energy is lost as heat
 * 1st and 2nd Laws of Thermodynamics

What ideas to students need to understand before they can address the topics described above?

 * What is a phase change
 * Phase diagrams of pure substances
 * Conservation of energy is similar to conservation of matter.
 * Definition/understanding of spontaneous
 * Definition of equilibrium
 * Definition of endo- and exo-
 * Catalysts
 * Difference between adding heat to start a reaction and a reaction that results in higher temperatures.
 * Types of measurable energy: heat, light, etc

What misconceptions are students likely to have about these topics?

 * Students think energy disappears
 * Think "Transformation" = destruction or loss
 * Think cold is a type of energy, or that cold can be transferred
 * Fail to make the link between heat energy and increased kinetics
 * Think heat = temperature, not energy
 * Think sound = energy
 * Think there is no relation between energy and matter
 * Think energy and force are interchangeable
 * Energy can be used up (like by an appliance or car)
 * Energy is a tangible object
 * Biological systems do not follow same rules of thermodynamics
 * Objects of different temperatures which are in constant contact with each other, or in contact with air at a different temperature, do not necessarily move toward the same temperature.

What phenomena and representations help students understand these topics?
From http://antoine.frostburg.edu/chem/senese/101/thermo/faq/exothermic-endothermic-examples.shtml Author: [|Fred Senese] senese@antoine.frostburg.edu