Current Electricity Current electricity refers to the flow of charged particles from a region of high electric potential energy to a region of low electric potential energy. Try to imagine what your life would be like without all the devices that run on current electricity! Gravitational Potential Energy When raised up high, the mass has a lot of gravitational potential energy. When the mass is released, it converts its potential energy into kinetic energy. Electric Potential Energy When held apart, the positive and negative charge have a lot of electric potential energy. Upon release, the two charges move together, converting their potential energy into kinetic energy. Electric Potential When you place different amounts of charge in an electric field, they will each have different amounts of electric potential energy, even if you put them in the same place. Therefore, it is much more convenient to talk about the electric potential energy per unit of charge. This is called electric potential. Differences in electric potential we know as voltage! Electrical Pressure It is much easier to think of voltage as a kind of electrical “pressure” between two places. It is caused by a difference in electric potential energy. Just as water pressure makes water flow through a pipe, voltage or electrical pressure causes electric charges to flow along a wire. Water Pressure Water naturally flows from the tank at higher pressure to the tank at lower pressure. A Complete Circuit By adding a pump to put energy back into the system, we can keep the water flowing perpetually. A Complete Electrical Circuit Think of the battery as a pump. Chemical reactions inside the battery exert a strong force on the electrons in the wire, making them flow out of the battery, through the light bulb, and then back into the battery. The electrons are never used up. The are naturally recycled around the circuit. The Electric Light Bulb As electrons squeeze their way through the thin wire filament of the light bulb, they bump into many atoms, transferring some of their energy to them. Their gain in energy makes the filament get hot and glow. The battery's chemical energy has been changed to electrical energy which changes to heat and light. Electric Current Electric current is defined as the flow of electric charge. amount of electric charge current= amount of time Current is measured in amperes. Electrical Resistance Different materials are not all equally good at conducting electricity. A substance's resistance is a measure of how difficult it is for electric current to flow. Ohm's Law Resistance is measured in ohms. V R= I voltage resistance= current Electrical wire electrons voltage current resistance switch Plumbing pipe water water pressure gallons per minute restrictions to flow faucet or valve