VOLTS

There is a relationship between amperes and watts. They are not totally separate. To understand this, we need to add "voltage" to the mix. You've probably heard that voltage is like electrical pressure. What's usually not taught is that voltage is a major part of static electricity, so whenever we deal with voltage, we're dealing with static electricity. If I grab electrons away from a wire, that wire will have excess protons left behind. If I place those electrons into another wire, then my two wires have oppositely-imbalanced charge. They have a voltage between them too, and a static-electric field extends across the space between them. THIS FIELD *IS* THE VOLTAGE. Electrostatic fields are measured in terms of volts per distance, and if you have an electric field, you always have a voltage. To create voltage, take charges out of one object and stick them in another. You always do this when you scuff your shoes across the carpet in the wintertime. Batteries and generators do this all the time too. It's part of their "pumping" action. Voltage is an electrostatic concept, and a battery is a "static electric" device.

Remember the battery in the copper ring from above? The battery acted as a charge pump. It pulled charge-stuff out of one side of the ring, and pushed it into the other side. Not only did this force the circle of charges to begin moving, it also caused a voltage-difference to appear between the two sides of the ring. It also caused an electrostatic field to appear in the space surrounding the ring. The charges within the copper ring began moving because they responded to the forces created by the voltage surrounding the ring. In this way the voltage is like pressure. By pushing the charges from one wire to the other, a voltage causes the two wires to become positive and negative... and the positive and negative wires produce a voltage. (In hydraulics we would use a pressure to drive water into a pipe, and because we drove water into a pipe the pressure in that pipe would rise.)

So, the battery "charged up" the two halves of the copper ring. The light bulb provided a path to discharge them again, and this created the flow of charge in the light bulb filament. The battery pushes charge through itself, and this also forces a pressure-imbalance in the ring, and forces charges to flow through the light bulb filament. But where does energy fit into this? To understand that, we also have to know about electrical friction or "resistance."