Resistance of wire :: essays research papers

IF YOU INCREASE THE VOLTAGE - MORE CURRENT WILL FLOW. IF YOU INCREASE THE RESISTANCE - LESS CURRENT WILL FLOW (UNLESS YOU INCREASE THE VOLTAGE).' Ã ³`In Metals The Current Is Carried By Electrons 1. Electric current will only flow if there are charges, which can freely move. 2. Metals contain a sea of "Free Electrons" (which are negatively charged). And flow throughout the metal if they are given energy. 3. This is what allows electric current to flow so well in materials.' Ã ³`Resistance Resistance is anything that causes an opposition to the flow of electricity in a circuit. It is used to control the amount of voltage and /or amperage in a circuit. Everything in a circuit causes a resistance (even wire). It is measured in OHMS (Ω). Resistance occurs when the electrons travelling along the wire collide with the atoms of the wire. These collisions slow down the flow of electrons causing resistance. Resistance is a measure of how hard it is to move the electrons through the wire. The resistance of a wire depends on the number of collisions the electrons have with the atoms there will a larger number of collisions which will increase the resistance of the wire. If a length of a wire contains a certain number of atoms, when that length is increased the number of atoms will also increase. E.g. If there is a wire that is half the length of another wire it would also have half the number of atoms, this means that the electrons will collide with the atoms half the amount of times. Also if the length of the wire is trebled or quadrupled then the resistance would also treble or quadrupled.' My prediction was derived from this information. All of this information I collected originated from the Website, "www.studentcentral.co.uk" from encyclopaedias such as "The Oxford Children's Encyclopaedia" and computer encyclopaedias such as "Encarta". Ã ³This scientific information relates to my experiment by stating that the longer the lengths of wire the higher the resistance. Ã ³Preliminary Results Length Of Wire (mm): Voltage (V): Current (A): Resistance (Ω): Ã ³Therefore this information supports my prediction that the longer the length of wire the higher the resistance. Obtaining Evidence: Ã ³The variables I kept the same are: Ã ´The same material used for the wire, Ã ´The same cross-sectional area of wire, Ã ´And the same temperature of the wire. Ã ³The potential difference from the power pack: 2V.