Electromagnetism Investigation Essay, Research Paper
Physics – Electromagnetism Planning Previous Scientific Knowledge. When insulated wire is wrapped round an iron nail and the ends of the wire are connected to a battery the nail becomes capable of picking up iron filings and paper clips. This is called an electromagnet. The nail is magnetised by the current in the wire. If the battery is disconnected then the iron clips will fall off. This is because most of the magnetism has been lost. The passage of an electric current along a wire creates a magnetic field around the wire. The fields are in the shape of a series of concentric rings. The more coils used in the electromagnet, the stronger the magnet is. If there is one coil, and another is added, then the two coils have twice the strength of one. This is because the current going through the wire makes the soft-iron core is the factor that induces electromagnetism, as so when there is more current, there will be more wire or or a more magnetised core. Magnets were formed when certain molten metals, (iron, nickel and cobalt,) cool . Normally when the atoms in a non magnetic crystallise, the atoms point in random directions. But because of the properties of the metals mentioned, these atoms line up into parts of the magnetic with similar directions called domains. This is because the earth has a magnetic field, and the atoms in the metal all follow the these magnetic lines and form these domains. This is similar to what happens when an electromagnet is formed. Prediction I think that the more current that goes through the wire, the greater the electromagnetic pull of the soft-iron core will be. This is because the current going through the wire makes the soft-iron core is the factor that induces electromagnetism, as so when there is more current, there will be more electromagnetism. This is the same with the the number of coils,ed with the electromagnet, the more power is returned. The return and investment are not directly proportional. I think this because of the aforementioned scientific knowledge. Aim In this experiment we want to test the power of an electromagnet when the: -number of coils are varied -when the amount of current is varied Preliminary Experiment. In this experiment we experimented with different ways of testing the strength of the electromagnet. We also discovered which was the best core to use, how many coils to use, when the wire melted, and which was the best current to use. We did this by setting up the experiment as shown below and then changing different factors in it, such as the core and number of coils. Apparatus Electromagnet. Crocodile 2.5 M Wire Ammeter Small Yellow Connector wire. Power Pack Soft Iron Core Method-Experiment 1 1) A 2.5 m electrical wire will be coiled around around a soft-iron core 30 times. 2) Crocodile clips will be connected to yellow connecting wires at each end. 3) These together with the ammeter will be connected up to the power supply as shown in the circuit diagram. 4) A fixed amount of iron filings will be poured over the electromagnet with the power switched on. 5) The wire will be shaken until no more iron filings come off. 6) The power will be turned off. All of the iron filings that drop off will be weighed. I will vary only the current in this experiment. All other factors will be kept constant. I will measure the amount of iron filings at 1,2,3,4 & 5 amps. I will repeat each experiment three times for accuracy. Method-Experiment 2 1) A 2.5 m electrical wire will be coiled around around a 2) Crocodile clips will be connected to yellow connecting wires at each end. 3) These together with the ammeter will be connected up to the power supply as shown in the circuit diagram. 4) A fixed amount of iron filings will be poured over the electromagnet with the power switched on. 5) The wire will be shaken until no more iron filings come off. 6) The power will be turned off. All of the iron filings that drop off will be weighed. I will vary only the number of coils in this experiment. All other factors will be kept constant. I will measure the amount of iron filings at 10,20,30,40 & 50 coils of wire. I will repeat each experiment twice for accuracy. X will be equal to 10,20,30,40 & 50 coils of wire. Safety Precautions We will make sure that there is no bare insulation or any water near any electricatical equipment to prevent electroc Bibliography I used Key Science: Physics to help me with my planning. Note I might need to repeat some results that show no correlation to the other results, if they are drastically wrong. Factors Affecting The Experiment: 1) Current- This will change in one experiment. This will be kept constant by observing the ammeter and correcting any fluctuations on the D.C power pack. 2) Magnetic strength of the Soft-Iron Core. This will affect the power of theelectromagnet. It will be kept constant by using the same soft-iron core. 3)Way in which the wire is coiled. If the coils are coiled towards end, then one end will be more powerful than the other, and affect the results. I will try to keep the shape of the coils uniform. 4) Way in which the iron filings are shaken. The harder the the magnet is shaken, then the more iron filings will be dropped, and the more the weight will change. Analysing Evidence Clear Patterns: Method-Experiment 1 Here there is a very clear curve a the beginning, but the final three amps there is a similar per amp rate of increase suggesting that unlike experiment 2. This shows that one amp does increase the magnetic power one unit- the more expended, the same return on the investment. It is dissimilar to a thermistor current vs. resistance graph, and similar to a resistor current vs. resistance graph. Conclusions-Experiment 1 The Scientific Explanation-Experiment 1 As the current is passed on to the wire, it becomes a magnet itself, in accordance with the right hand rule. It magnetises the ÔsubstanceÕ at the core. Inside the ÔsubstanceÕ there are domains. When they are magnetised they aligned themselves onto the same direction , making it magnetic, This needs energy to perform and maintain the process, it is not cumulative so the more energy put into it the more will come out. Clear Patterns: Method-Experiment 2 This is similar to experiment one, except there is a curve is. Here there is a very clear curve. It starts very closely and then raises increasingly rapidly. It starts of very slowly and then as more power is put in, it rises faster and faster. This shows that one coil does not increase the magnetic power one unit- the m Conclusions-Experiment 2 The number of coil around an electromagnet is not proportional to the electromagnetic strength. Scientific Explanation-Experiment 2 When more coils are in contact with the core, which is what the experiment shows, more area of interaction is available, allowing more domains to be magnetised quicker than if the area is smaller. So if there is more area, the magnetic area will become stronger. there is a kind of activation energy.