In many ways, electricity behaves like water. When stored up, it has the potential to go somewhere. When it flows, it wants to take the path of least resistance. To further understand how electricity is measured, let's compare it to water.
Think of a water tank filled with water mounted on a pole. The water in the tank is the potential energy. If you hook a hose to the water tank, and open the valve, the water will flow out the hose. The higher the water tank is on the pole, the faster the water will come out. This is known as water pressure. When measuring electrical pressure, the unit of measurement for pressure is called voltage, or, V in its shorthand. Work performed by electricity is called power or, P in its shorthand. The measure of current is called amps. The formula is known as E=I x R, which is called Ohms Law.
Remember the water valve you turned on to let the water out of the tank? You controlled the amount of water with the valve by impeding the flow of water. In other words, you gave resistance. In electricity, resistance is measured in ohms, frequently expressed with the symbol, and named after the guy who discovered the math relationship between voltage, current, resistance, and power. The shorthand for ohms is either or R.
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