ELECTRIC CURRENT IS A FLOW OF ENERGY?
November 15, 2010 Leave a comment
Wrong. Electric current is a flowing motion of charged particles. The words “Electric Current” mean the same as “charge flow.” Electric current is a very slow flow of charges. On the other hand, electric energy is made of fields and it moves VERY rapidly. Electric energy moves at a different speed than electric current, so obviously they are two different things. Unless we realize this, we won’t understand how circuits work. Indeed, we will have little basic grasp of electrical science. In an electric circuit, the path of the electric charges is circular, while the path of the energy is not. A battery can send electric energy to a light bulb, and the bulb changes electrical energy into light. The energy does NOT flow back to the battery again. At the same time, the electric current is a circular flow, and the charges flow through the light bulb filament and none are lost. Electric energy can flow in a direction opposite to that of the electric current. In a single wire, electric energy can even move continuously forward while the direction of the electric current is alternating back and forth at high frequency. Here’s one way to clarify the muddled concepts: if electric current is like a flow of air inside a pipe, then electrical energy is like sound waves in the pipe, and electrons are like the air molecules. Sound can travel through a pipe if the pipe is full of air molecules, and electrical energy can flow along a wire because the wire is full of movable charges. Sound moves much faster than wind, correct? And electrical energy moves much faster than electric current for much the same reason. Air in a pipe can flow fast or slow, while sound waves always move at the same very high speed. Charges in a wire can flow fast or slow, while electrical energy always flows along the wire at the same incredibly high speed. Whenever sound is flowing through a pipe, the air molecules in that pipe are vibrating back and forth. When waves of AC electrical energy are flowing along a wire, the electrons in that wire are vibrating back and forth 60 times per second. What if we were all taught that sound and wind are the same thing? This would prevent us from understanding wind or sound. Books teach us that electric currents are a flow of energy, and it prevents us from understanding both current and energy flow. Be careful, since my description of the above pipes are just an analogy, and sound waves aren’t *exactly* like electrical energy. For example, sound can flow inside an air-filled tube, while electrical energy always flows in the space outside of the wires, and does not travel along within the metal wires. However, electrical energy is coupled with compression waves in the electrons of the wire surface. Electric energy is composed of electric and magnetic fields, and it exists in the space surrounding the wires. Electric energy is very similar to radio waves, but it is very low in frequency. Electric CHARGE is very different than the energy. The charge-flow (current) is a flowing motion usually of electrons, and electrons are material particles, not energy particles. And it’s not always a flow of electrons: when electric current exists inside an electrolyte (in batteries, salt water, the earth, or in your flesh) it is a flow of charged atoms called ions, so there is no denying that it is a flow of material. Current is a matter-flow, not an energy flow. Is it important for us to realize that wind is not sound? Obviously. School books would cause harm if they taught us that wind is sound. And if we want to understand circuits, we need a clear view of electric charge flow, and of electric energy flow. We need to be totally certain that they are two different things, and our textbooks teach us the exact opposite!