What is the Difference Between Energy and Power?

   The study of the concepts of energy and power is one of the cornerstones of the science of Physics. Think of Isaac Newton and Albert Einstein when you think of Physics. Don't forget Archimedes. It is easy to say "Energy is the potential to do work".  What  do we mean by "work"?

    Probably the first scientific definition of work came from the Greek philosopher Archimedes, force times distance. One example would be to lift a pound of weight one foot. This is one foot pound of work. If you have to move a one ton box from one side of a room to the other, it takes less work to move it if it is on wheels than it does if you have to slide it across the floor(unless the floor is very slippery).

   Power is the rate at which work is done. One horse power is 33,000 foot pounds per minute (depending on how you define horsepower).  A watt is another measure of power, and a Kilowatt hour is another measure of energy. A physicist will have a much more complex understanding of what energy is. The science behind the atom bomb comes from that understanding.
 
   Consider 20 gallons of gasoline. Gasoline has energy stored in it (mostly originally derived from sunlight by ancient primitive plants). All methods of extracting that energy are less than perfect. Fuel cells are probably the most efficient, while internal combustion engines are pretty inefficient. Any system that burns gasoline is limited in its efficiency.

   Modern hybrid cars may be able to travel 2,000 miles on that 20 gallons of gas. A 1950 King Midget car will be able to go well over 1,000 miles on it at maybe 40 mph, while a top quality drag racer will be able to do a few quarter mile runs on it in a few seconds per run. What would be really nice is a powerful car that is efficient. An electric car with fuel cells has that possibility.

   A fuel cell is like an electric battery that converts the the energy stored in various fuels directly into electrical energy. A fuel cell provides electricity as long as it has fuel. The efficiency rates are high but the power output of fuel cells still needs improving . This sounds like a subject for another blog.