Energy Concepts
Basic Terms
Power: noun- a source or means of supplying energy.
Electricity: noun- a form of energy resulting from the existence of charged particles (such as electrons or protons), either statically as an accumulation of charge or dynamically as a current.
Energy in Daily Life
Nuclear Energy
Nuclear energy is released through either of two processes, one which involves joining atoms together, as with nuclear fusion, and the other which separates atoms, as occurs during nuclear fission. The most common example of nuclear energy is nuclear power plantsfor commercial power generation.
Thermal Energy
Electrical Energy
Electrical energy is the energy carried by moving electrons in an electric conductor. When electrons are forced along a path in a conducting substance such as a wire, the result is energy called electricity. Anything we use in daily life that requires a battery or electricity to run is considered and example of electrical energy.
Mechanical Potential Energy
Mechanical Kinetic Energy
Energy Units
ex) A kilocalorie is often used to describe food energy.
Joule: is the International System unit of electrical, mechanical, and thermal energy.
ex) An average person sitting quietly produces 100 J of heat every second.
Watt: defined as one joule per second; measures the rate of energy conversion or transfer; applies to thermal, electrical and mechanical energy.
ex) A typical household incandescent light bulb has a power rating of 25 to 100 watts.
BTU: British Thermal Unit; is a traditional unit of energy equal to about 1055 joules; is the amount of energy needed to cool or heat one pound of water by one degree Fahrenheit; describes the heat value (energy content) of fuels.
ex) One gallon of oil equals 140,000 BTU.
kWh: is a unit of energy equal to 1000 watt hours or 3.6 megajoules; applies to mechanical, electrical and thermal energy.
ex) The kilowatt hour is most commonly known as a billing unit for energy delivered to consumers by electric utilities.
Horsepower: is the measurement of power, the rate at which work is done; applies to electrical mechanical and thermal energy.
ex) The Ford F-150's engine has 411 horsepower.
Laws of Thermodynamics
ex) When a moving car hits a parked car and causes the parked car to move, energy is transferred from the moving car to the parked car.
ex) In a diesel engine, not all energy will be available from the diesel gasoline because some will "leak" as heat and friction.