Chapter 2.1 Forms of Energy

Chemical Energy  Alchemists first tried to make gold by mixing the 4 known elements (earth, air, fire, and water).  From this, the study of chemistry began  Chemical energy is the potential energy stored in the chemical bonds of compounds.

Electrical Energy  The work done by moving charges.  Alessandro Volta invented the Volta Pile (see Fig 2.2 on pg. 165)  This was the first battery  It provides evidence of chemical energy and electrical energy  The study of current electricity and electrical energy began

Magnetism  Hans Oersted discovered that an electric current in a wire could produce magnetic effects (See Fig 2.5 Pg. 166)  This led to the invention of the electromagnet

 Michael Faraday moved a magnet through a coil of wire and saw that this caused an electric current to flow through the wire (opposite of Oersted) (See Fig 2.4 Pg. 166)  Thomas Seebek showed that heat could be converted into electricity.  Thomas Edison showed that heat and light are forms of energy that could be produced from electricity

Nuclear Energy  1896 – Henri Becquerel observed that certain atoms spontaneously disintegrate and emit radiant energy.  Nuclear energy is the potential energy stored in the nucleus of an atom  Nuclear fission is when the nucleus of an atoms splits  Nuclear fusion is when the nuclei of two atoms combine  These reactions are the source of the Sun’s energy

Solar Energy  Solar energy results from a hydrogen- hydrogen nuclear fusion reaction with the release of nuclear energy  This energy travels to earth as electromagnetic radiation  Scientists realized that if the source of the Sun was chemical energy from burning, it would burn up in 5000 years

Motion and Energy  Gottfried Leibniz called the physical quantity of energy vis viva (living force)  1850s – it was called energy  Two types of energy observed in nature  1. flowing water, wind, or object in motion – kinetic energy  2. An object raised above the earth has – gravitational potential energy  The sum of the energy of motion and position is known as mechanical energy

Heat and Energy  Atomists (Greeks) thought that heat was related to motion of “atoms”  1750 – Joseph Black – Thermodynamics is a science dealing with the study of heat, work, and energy  The transfer of thermal energy from a hot object to a cold object is defines as heat

Heat and Mechanical Energy  Benjamin Thompson – realized heat and mechanical energy are related  Led to current definition of energy – capacity to do work

Joule’s Experiments  Sadi Carnot – discovered that the transformation of heat into mechanical energy could only occur when thermal energy flows from a hot object to a cool object. Heat is always lost  See experiment on Page 170.