Forms of Energy
Energy is Fun!
Energy comes in many flavors! Kinetic Energy Potential Energy Thermal/heat Energy Chemical Energy Electrical Energy Electrochemical Energy Electromagnetic Radiation Energy Sound Energy Nuclear Energy
Kinetic Energy (KE) Motion! An object with kinetic energy (or any other form of energy) has the ability to do work, e.g. transferring its energy by pushing or deforming another object KE = ½ m v 2 Example: a flying baseball
Potential Energy (PE) In the narrowest sense: gravity can accelerate an object with potential energy (performing work on it) Note that potential energy depends on a relationship between two bodies. Potential energy can be converted to kinetic energy by acceleration due to gravity. PE = mgh Example: book on a shelf
Thermal, or Heat Energy Actually a microscopic version of kinetic AND potential energy as molecules bounce off each other and are alternately attracted to and repelled from other molecules Temperature is a measure of thermal energy Example: hot cup of coffee
Chemical Energy Actually a microscopic version of potential energy When molecules react with each other and rearrange themselves, they may release or consume energy Example: combustion engine, muscles consuming glucose
Electrical Energy Actually a microscopic version of kinetic AND potential energy as electrons interact with one another If they are pushed by a force ( voltage, potential or emf ), a chain reaction of electron interactions results each electron interacting with and repelling the next one Especially true in a conductor, although all materials conduct to some degree Example: electric motor, generator
Electrochemical Energy Similar to chemical energy (which is itself a combination of kinetic and potential energy), but specifically results in the flow of electrons electrical energy. Example: battery, fuel cell
Electromagnetic Energy Electromagnetic radiation, e.g. from the electromagnetic spectrum The entire electromagnetic spectrum can be considered oscillating, coupled electric and magnetic fields waves radiation has a specific wavelength and frequency Can also be considered particles (photons) discrete packets of energy Example: light from sun
Sound Energy Actually a combination of kinetic energy (vibration) and potential energy (compression) of particles Takes the form of waves, with a specific frequency Example: speakers
Nuclear Energy Reactions that involve interactions with a molecule s nucleus. Atom nuclei are tightly bound large amount of potential energy compared to electron interactions Nuclear reactions result in large amounts of heat and radiation E = mc 2 Example: stars (fusion), nuclear reactors (fission)
Forms of Energy Kinetic Energy Potential Energy Thermal/heat Energy Chemical Energy Electrical Energy Electrochemical Energy Electromagnetic Radiation Energy Sound Energy Nuclear Energy but really, these are redundant! We can classify all of these into macroscopic and microscopic versions of kinetic and potential energy.
Energy Laws (1) Energy comes in many flavors or forms. Kinetic, Potential, Thermal/Heat, Chemical, Electrical, Electrochemical, Electromagnetic Radiation, Sound, Nuclear
(2) Energy Laws Energy can be transferred between objects or systems through various types of interactions. Thus, total energy content is not an intrinsic property of a material, like color or density.
Energy Laws (3) Energy is always conserved; it is never created or destroyed. This is known as the First Law of Thermodynamics
(4) Energy Laws Energy can be converted from any form into any other form, subject only to the Second Law of Thermodynamics. Second Law of Thermodynamics: The entropy of an isolated system never decreases. Equivalently: natural processes have a preferred direction (Ex: heat flows in one direction unless work is performed on the system).
Questions? Matt Aldeman Senior Energy Analyst Center for Renewable Energy Illinois State University maldema@ilstu.edu (309) 438 1440