Electricity and Magnets Study Guide Electricity An electrical current is the flow of electrons. A closed circuit has all connections and lets the electrons flow without interruption. There are at least 3 connections. An open circuit does not let the electrons flow. There is some interruption of flow. A battery stores energy and has two ends, one positive and one negative. Electrons flow from the negative end of the battery through a wire to a switch or a bulb then back to the positive end of the battery. A series circuit is wired in a complete circle, or path, positive to negative. The advantages of a series circuit are that when you add more volts the bulb is brighter. The disadvantages are that when one bulb or battery is removed the circuit becomes open and the bulbs go out. A second disadvantage is that the batteries don’t last as long as in a parallel circuit. A parallel circuit is wired in separate paths. Batteries are connected positive to positive ends and negative to negative ends. The advantages of parallel circuits are that if one battery or bulb is removed the circuit will stay closed. Another advantage is that the batteries will last longer. The disadvantages of a parallel circuit are that the bulb is not as bright and you have to use more wires. An insulator is a material that does not allow an electric current to flow easily. Ex. plastic, rubber, paper, glass A conductor is a material that does allow an electric current to flow easily. Ex. metal, copper, aluminum Static electricity have electrons that do not move but still create an electrical charge. Magnets Like poles repel. Opposite poles attract.