How The Length Of A Wire Is Affected By The Resistance
0 User(s) Rated!
Words: 3147 Views: 218 Comments: 0
Introduction To investigate how the length of a wire affects resistance in an electric circuit, different lengths of wire will be placed in an electrical circuit and the effects will be observed. An ammeter and voltmeter will be used to measure the current and voltage in the circuit. Then, resistance will be worked out by dividing the voltage by current. Resistance is the measure of how hard it is for electricity to push through a circuit. All conductors resist the flow of current to some extent. Howeaver, some resist more than others. The...
Overall, the experiment went well as the data fully supported the prediction, with the exception of one outlier (the average of the 50cm wire test). The prediction was based on the theory that the longer the wire, the further the current has to travel which gives a longer amount of time that the current is travelling against the ions creating resistance (as explained in further detail previously in the Introduction). The fact that the data supported the prediction shows that the experiment was carried out well with at least an adequate amount of accuracy as it produced the results expected.

Become A Member Become a member to continue reading this essay orLoginLogin
View Comments Add Comment

Aim:- We will investigate... Aim:- We will investigate the length of a wire in a series circuit, and if it will affect its resistance. Prediction:- Resistance is the force of which opposes the flow of an electric current around a circuit so that energy is required to push the charged particles around the circuit. I predict the resistance will vary with the length. I also predict the longer the wire the less current will flow which increases the resistance. This is because electric current is the movement of electrons through a conductor, so when resistance is high, conductivity is low. Therefore, the electrons will have to push their way through a shorter path of atoms in the wire, reducing their resistance. Whereas, if the length was longer, then the number of atoms in the wire increase. Electrons are negatively charged particles, and protons are positively charged atoms. Electrons move around, but protons don't move, they stay in the same place. Current is a flow of electrons, and is measured in amperes A. When a current flows through a resistance, energy is given off as heat. I think the thicker and shorter the wire, the lower the resistance. I think this because, for example, if you had a road with cars parked to the side and only one car at a time can pass the cars parked on the side of the road as the road is so narrow that allows two cars to go at a time, but as it seems that there are cars parked, that only one car can move past the parked cars; in this case it will be slower for the cars to pass, because the road is long and narrow. Whereas, if the road was wider thinker and shorter it would be quicker. DIAGRAM OF THE THICKNESS AND LENGTH Planning:- Before I do start my investigation I will need to set up my circuit. I will need a variable resistor connected to a power supply, an ammeter and a voltmeter voltmeter parallel to the nichrome wire. I will move the knob on the variable resistor into five different positions for each one length e.g:- 10cm, 20cm, 30cm "¦"¦.. I will get five different readings for each length, and I will be doing five different lengths, which makes twenty-five readings all together, on the voltmeter and ammeter. I will calculate the resistance with this equation:- V = R x I OR Potential difference volts, V = Current amps, A x Resistanceohm, This is how my circuit will look like when I've finished setting it up:- DIAGRAM OF CIRCUIT I will link all the components together with the wire connected to the circuit with crocodile clips at the length of 10cm. I will use to measure the voltage using a voltmeter and recording the results on a table. I will also need to measure the current using an ammeter and recording the results for them too. When I have the results I require, I will use the calculator and divide the voltage by the current to get the resistance. I know that I will need to turn off and on the power supply every time I investigate another length of the wire. This is because the wire intends to warm up and this may have an effect on my other readings and also the wire can snap in half by melting. To keep my investigation fair, I will keep the voltage on the power supply the same, the type of wire and the thickness, and also do the investigation in the same surrounding temperature. Analysing:- I have calculated the resistance of each length on the nichrome wire. I have used these results of values to plot a graph of resistance against length. Length goes along the bottom axis because it is the dependent variable. Its value depends on the length of the wire chosen The points on my graph are a little scattered, none of the points touch the line of best fit, but they are quite close together.. On my graph of the length against gradient, I have rejected one point. I would of rejected two, but I have noticed that the 10cm point was very high, I was going to also reject the 40cm point too, but I was more curious on the 10cm. my table of results suggests that the voltage reading for one point in the 10cm trial was very high compared to the other results of 20cm, 30cm, 40cm and 50cm. but I reckon that I must of miss read the meters whilst investigating. I have noted my working out on the graph of current against voltage. On my graph of current against voltage, there is an anomalies point which I have circled. It is the 10cm point of 0.90V and 0.18A which I must have rejected on the graph of length against gradient. So this is the reason of my rejection on the graph of length against gradient. You can see that this one point has affected the gradient. And as I mentioned that I must of miss read the meters.   

Aim:- We will investigate the length of a wire in a series circuit, and if it will affect its resistance. Prediction:- Resistance is the force of which opposes the flow of an electric current around a circuit so that energy is required to push the charged...

Words: 874 View(s): 207 Comment(s): 0
Mankind has always been fascinated with...Mankind has always been fascinated with the thought of what everything is made of. The answer can be found in the periodic table but that hasn't always been the case"¦"¦"¦ Once upon a time in a kingdom far, far away live a Greek scientist called Aristotle shown right. Around 300BC he declared that every thing is made up of only four elements. These were fire, air, water and earth and that all matter is made up of four elements. Also that matter had four properties, hot, cold, dry and wet. But this did not satisfy ever one and so the next person to challenged this idea was the idea of Hennig Brand. Brand was the first person to discover a new element. He was a bankrupt German merchant who was trying to discover the Philosopher"s Stone which was supposed to turn inexpensive metals into gold. He experimented with distilling human urine until in 1669 he finally made a glowing white substance which he named phosphorus. He kept his discovery secret, until 1680 when Robert Boyle rediscovered it and it became public. Then later in 1789 Antoine-Laurent de Lavoisier shown here released his Traité Élémentaire de Chimie it was thought to be the first chemical text book. It contained a list of elements, or substances that could not be broken down further, which included oxygen, nitrogen, hydrogen, phosphorus, mercury, zinc, and sulphur and a further 26 what he thought to be elements. While many leading chemists of the time refused to believe Lavoisier"s new revelations, the Elementary Treatise was written well enough to convince the younger generation. This model only classified elements into metals and non-metals and so was not accepted. The next knight in shining armour to continue the periodic table legassy was Jons Jakob Berzelius who introduce a table of atomic weights. In his weights, he used oxygen as a standard, setting its weight equal to exactly 100. He also measured the weights of 43 elements. This paved the way for the German chemist Johann Dobereiner right. In the 1820s Döbereiner noticed an interesting pattern in some sets of three similar elements. He noticed that the atomic mass lay roughly halfway between the lightest and heaviest ele ments in the group of three. He called this group the triads. Then many elements had not yet been discovered and some substances were thought of as elements that were actually compounds. So it"s not surprising that Döbereiner could only find a few triads. Certain triads were calcium, strontium & barium and chlorine, bromine & iodine. Then came along the British chemist John Newlands. In 1864 he suggested that if the elements are put in order of atomic mass, every eighth element was similar. He called this his Law of Octaves. This pattern only worked for the first 15 or so elements known at that time. Fellow scientists at the time were not very impressed. Some big bad wolves even said that he might have had better luck putting the elements in alphabetical order. It was a few years later that the real breakthrough came. A Russian chemist called Dmitri Mendeleev shown hard at work was also struggling to find any underlying pattern in the chemistry of the elements. This knight in shining armor also thought that the key was to arrange the elements in order of atomic mass. But try as he might he didn't know why the pattern kept breaking down. He spent about 13 years gathering data on the problem and eventually solved it by deciding to leave gaps so that similar elements could always line up in vertical columns. Mendeleev enjoyed playing card game patience so he made a card for each element. This helped him working out his solution as he made lines of similar elements, one on top of another. Eventually he published what he called his " Periodic Table'. At the time, many scientists doubted Mendeleev"s theory because he left gaps and changed the order of elements to make his table work properly. However, he won them over by predicting the properties of elements that were as yet undiscovered from the patterns evident in his table. When the element germanium was discovered in 1886, it closely matched the properties Mendeleev had predicted using his Periodic Table. The science community of that time was dumbstruck at that Russian scientist and his new table, and today people still think it an extremely groovy piece of science. Mendeleev's table stood strong until the beginning of the 20th Century. The discovery of atomic properties led to the quantum theory which was a clever piece of science only understood by three or four magic wizards on this planet. The periodic table of the elements was reorganized to accommodate this new theory, made to look like how we know it today. The original sorting organized by Mendeleev was dropped in favor of the more logical sorting according to the atomic number and the groups were arranged according to their electronic configuration. *Even now the periodic table of the elements as we know it is not complete and every now and again a knight steps forth and takes on the legacy of his fore fathers and a new element is synthesized and added to Periodic table. And so the Periodic table was used for ever more and that is why its founders will live happily ever after.   

Mankind has always been fascinated with the thought of what everything is made of. The answer can be found in the periodic table but that hasn't always been the case……… Once upon a time in a kingdom far, far away live a Greek scientist called Aristotle shown right. Around 300BC...

Words: 900 View(s): 507 Comment(s): 0
The following shows the collision theory...The following shows the collision theory used to explain the effect of temperature and concentration Prediction: In this investigation I expect to find as I increase the temperature the reaction will take place faster. This is because as the temperature increases, it gives more energy to the sodium thiosulphate and hydrochloric acid particles causing them to collide more often and with more force; this increases the rate of reaction. As the temperature rises, a greater number of sodium thiosulphate and hydrochloric acid particles have energy greater than the activation energy therefore leading to more successful collision, and increasing the rate of reaction. * Plan: I will be mixing the two clear liquids 'Hydrochloric Acid' 1M "“HCl and 'Sodium Thiosulphate Solution' 40G/L - Na2S2O3, in order to observe and analyse the reaction changes if any when I increase the temperature. I will add 50cm of weak sodium thiosulphate and 5cm of hydrochloric acid into the beaker; I will make a quick mix of the solution before beginning to start the clock. I will watch the reaction and try to find out whether the solution goes milky and the cross disappears, this will indicate whether the reaction is done. Once the cross has disappeared in the solution I will stop the clock and record the results. Place Apparatus in middle of desk: Boiling tube, test tube, 600ml beaker, kettle, Distilled water bottle, Sodium Thiosulphate, Hydrochloric Acid, Stop Clock, Paper Cross, 25ml measuring cylinder, 100ml measuring cylinder and 10ml measuring cylinder. I will then draw a cross of any size on a piece of A4 paper Prepare Batch of sodium thiosulphate and distilled water using both a 100ml and 25ml measuring cylinders. Place 10cm of Hydrochloric acid into test tube using 10ml-measuring cylinder. Place 50cm of sodium thiosulphate/distilled water solution into boiling tube using a 25ml-measuring cylinder. Put water in kettle and switch on Place a cross on the outside of the 600ml beaker Place 150ml of cold water into 600ml beaker Mix the hot and cold water in beaker Use Thermometer to take the temperature of the sodium thiosulphate and distilled water and Hydrochloric acid with two thermometers in each test tube Wait for the temperature of both the Solution and Hydrochloric Acid to reach the required temperature Pour Hydrochloric acid into solution and start stop clock immediately Wait until cross disappears because of the cloudy solution, and then stop the stop clock Record the time in table Take the temperature of the mixture and record in table Pour away as soon as possible Wash boiling tube out with cold tap water then rinse with distilled water Take average of the start and finishing temperatures and times Repeat Experiments twice for each temperature to improve reliability or to make them reliable. Plot on graph The temperatures that I will carry out the experiments at 25, 30, 35, 40, 45°c. Fair test: I will be able to make this a fair test by keeping all of the solution the same amounts 50cm of weak sodium thiosulphate and 5cm of dilute hydrochloric acid. I will keep these variables the same: Concentration of 2HCl: Concentration of sodium thiosulphate and Hydrochloric acid "“ The concentration of sodium thiosulphate and hydrochloric acid will be kept the same, as to make it a fair test, because if you change the concentration of one reactant it changes the number of particles making the reaction unfair and not reliable. If you create batches of the reactants you reduce the percentage error of volume measurement and of the concentration. E.g. when you measure 25ml of water from a 25ml measuring cylinder a certain amount of water will stay in the cylinder, Then instead of water it was hydrochloric acid and some was left behind, it would change the total concentration because the number of particles has been reduced therefore there is less particles for the other reactant to collide with, also the chance of the amount left behind being the same will be small Volume of Na2S2O3: If I don't keep this constant then it'll effect the reation. Volume of 2HCl: if I don't keep this constant then it'll effect the reation. Temeperature of solution: If I don't keep this constant then it'll increase the energy of the particlesand also increase the chance of a successful collision. I will use the same cross for the whole experiment, also time it accurately and make sure my equipment is working. Equipment: Diagram *Sodium thiosulphate Hydrochloric acid Distilled water 2 Beakers Cross of A4 paper Burette Stopwatch Goggles Funnel Thermometer Water bath To follow this reaction you can measure how long it takes for a certain amount of sulphur to form. You do this by observing the reaction down through a conical flask, viewing a black cross on white paper see diagram below. The X is eventually obscured by the sulphur precipitate and the time noted. By using the same flask and paper X you can obtain a relative measure of the speed of the reaction in forming the same amount of sulphur. Mixè *èOngoing*èWatch stopped* Here is the preliminary result: * Safety: I will make the experiment safe by wearing goggles while handling the irritants and when the reactions are occurring during the experiment. Sulphur and sulphur dioxide are given off during the reactions and are irritants, if breathed in it is dangerous. To avoid this occurring I will keep the room well ventilated by opening windows so the gas can disappear. Each try I do I wash out the beaker several times before starting the experiment. I will make sure the hydrochloric acid does not get in contact with my hands. Analysis: The experiment shows, that when the hydrochloric acid is added to the sodium thiosulphate, a cloudy precipitate appeared. It also shows that when you increase the temperature at which a reaction is taking place, the particles move more quickly resulting in a faster reaction. This has two effects: 1 More collisions take place 2 When a collision occurs, there is more chance that the collision will lead to a reaction, because the amount of energy is more likely to be greater than the minimum amount of energy needed the activation energy Raising the temperature makes the particles move faster. This means that the particles collide more frequently with each other and the rate of the reaction increases. Also, the faster the particles are travelling, the greater is the proportion of them which will have the required activation energy for the reaction to occur. Refer back to prediction diagram HCl+sodium thiosulphatesodium chloride+sulphur dioxide+sulphur+water. HClaq + Na2S2O3aq NaClaq + SO2g + Ss + H2Ol Evaluation: I believe that my results, in general, were very much accurate as I repeated my experiment twice to be able to get an average time taken for the reaction to take place. Providentially, I had no anomalous results which proved the precision and accuracy of my experiment. The method did show the relationship between the temperature and the rate of the reaction. The line graph proves my hypothesis to be correct, but also provides me with some additional information. I have marked on the exact points of the average rate of reaction for every 5 ºC, you can see that at temp 30ºC the speed of reaction did not fall on the line of best fit. This was because the temperature was increased from the previous temp of 25ºC. At 25ºC, the particles would be moving quickly, but not as quickly as they are 30ºC, because as the temperature is increased the particles started moving more quickly and more frequently colliding with more energy so that a faster reaction occurred. Drawing in a line of best fit onto my graph, made it easier to get a more accurate picture from the results. My line graph showed positive correlation meaning that as the temperature was increased the rate of reaction increases. It's also a curve, levelling off gradually. For my Experiment, by having a 5°c rise in temperature allows the number of particles that have energy greater than the Ea Activation Energy 5.45times larger than the number before. This tells me that for this reaction the rate of reaction is almost double for a 5°c rise, therefore shows that the variables were controlled to a sufficient degree of accuracy to allow the reaction to take place at an optimum rate. The experiment was fair and reliable. However, to collect results that are far more accurate, I could have used a mechanical stirrer to act as a catalyst for speeding up the rate of reaction. This would become more precise and dependable. Another factor that we could have improved is the repetitions of experiments; I could have completed the test a further one more time to give me a more adequate average of my results. It was difficult to be able to get both the substances to the required temperature at the same time due to many human errors that can occur. Overall, from my investigation, I believe that the data provides sufficient evidence to support my collision theory as when I increased the temperature the rate of reaction increased. This has turned out to be a successful experiment.   

The following shows the collision theory used to explain the effect of temperature and concentration Prediction: In this investigation I expect to find as I increase the temperature the reaction will take place faster. This is because as the temperature increases, it gives more energy to the sodium thiosulphate and...

Words: 1538 View(s): 392 Comment(s): 0
Introduction What is electrical resistance?...Introduction What is electrical resistance? Electrical resistance is what limits the current inside a circuit. What effects resistance? "¢ Length: The longer the length of a wire the higher the resistance level will be. "¢ Diameter: The thicker the diameter of a wire the lower the resistance level will be. "¢ Material: Insulators have a very high resistance level and conductors have a very low resistance level. Metals are normally good conductors and plastics are very good insulators. In this assignment I am going to investigate how the length of a wire affects the level of resistance. Background Theory What is electrical current? Electrical current is the electron flow through a wire. Why are metals good conductors? Metals have free electrons inside a lattice of positive ions. This makes them very good conductors where insulators don't have free moving electrons. The electrons are very closely packed. Electrical current is electron flow. When electrons flow through a wire they collide with positive ions. The more collisions that take place between the electrons and the positive ions, the smaller the current is that flows the higher the resistance level is. Prediction I predict that if the length of the wire is increased then the resistance will also increase. I also predict that if the length of the wire is doubled the resistance will also double. When the length doubles the number of ions will double and due to this there will be double the amount of collisions. This will then cause the electron flow to halve and when the electron flow halves the current will also halve. This then causes the resistance level to double. If the length of the wire is then the resistance will also increase. If the length doubles then I believe the resistance will double and this shows the resistance is proportional to the length. Pre-test I am going to investigate the resistance change when the length of the wire is changed. The diameter of the wire will also affect the resistance so I am going to perform a pre-test to decide which diameter of wire I am going to use. I am going to use three different diameters and they are 0.55mm, 0.37mm, 0.27mm of constantan wire. Diameter = 0.27mm Length cm Voltage V Current A Resistance 20 2 1.4 1.43 20 1 0.75 1.33 50 2 0.6 3.33 50 3 0.8 3.75 Diameter = 0.37mm Length cm Voltage V Current A Resistance 20 1.6 1.8 1.56 20 2.0 2.3 1.57 50 2.6 1.3 3.70 50 3.3 1.7 3.88 Diameter = 0.55mm Length cm Voltage V Current A Resistance 20 0.8 2.3 0.35 20 0.4 1.2 0.33 50 1.8 1.9 0.95 50 1.2 1.7 0.71 From my pre-test results I can see that the wire that would be best to use would be the 0.55mm wire. The 0.27mm and 0.37mm wires got too hot after a short while and the 0.55mm wire did not increase in temperature. The rise in temperature, of the wire caused the resistance to increase because all the particles gained energy which caused them to move more which meant more collisions where taking place. Due to this I have chosen the 0.55mm diameter constantan wire. Plan Apparatus 0.55mm diameter constantan wire Ammeter Connecting wires Crocodile clips Meter ruler Power pack Variable resistor Voltmeter Diagram Method First I am going to set up my apparatus and then I am going to mark out nine different measurements and them being 10cm, 20cm, 30cm, 40cm, 50cm, 60cm, 70cm, 80cm and 90cm. I will move the crocodile clips, which are connected to the ammeter, voltmeter and constantan wire up every 10cm. I am then going to take the voltage for each measurement and also repeat the method three times. I am then going to divide the voltage by the current and my answer will be the resistance. I will then take an average of my three resistance results. My results charts will look like these. Length cm Voltage V Current A Voltage V Current A Voltage V Current A 10 20 30 40 50 60 70 80 90 Length cm Resistance 1 Resistance 2 Resistance 3 Average Resistance 10 20 30 40 50 60 70 80 90 Results Length cm Voltage V Current A Voltage V Current A Voltage V Current A 10 0.14 0.6 0.15 0.6 0.16 0.6 20 0.26 0.6 0.26 0.6 0.27 0.6 30 0.39 0.6 0.39 0.6 0.39 0.6 40 0.51 0.6 0.50 0.6 0.50 0.6 50 0.59 0.6 0.61 0.6 0.61 0.6 60 0.70 0.6 0.73 0.6 0.73 0.6 70 0.80 0.6 0.83 0.6 0.83 0.6 80 0.90 0.6 0.94 0.6 0.94 0.6 90 1.01 0.6 1.03 0.6 1.03 0.6 Length cm Resistance 1 Resistance 2 Resistance 3 Average Resistance 10 0.24 0.25 0.27 0.25 20 0.42 0.42 0.45 0.43 30 0.65 0.65 0.65 0.65 40 0.85 0.83 0.83 0.84 50 0.98 1.02 1.02 1.01 60 1.67 1.23 1.27 1.38 70 1.34 1.86/1.36 1.38 1.52 80 1.50 1.57 1.57 1.75 90 1.86 1.72 1.71 1.76 Analysis My graph shows that the resistance is proportional to the length up to 70cm and then it curves slightly after that. Up to 70 cm on my graph shows that my prediction was correct. I predicted that if the length of the wire doubled then so would the resistance. I took three readings off my graph: 15, 30 and 45. This is shown in the table below. Length cm Average Resistance 15 33 30 66 45 98 My table of results above shows that when the length doubles so does the resistance and when the length triples so should the resistance triple. This proves what I said in my prediction was correct that the resistance is proportional to the length. This can be explained because metals have free moving electrons in a bed of positive ions. All the free electrons will collide with the ions inside the wire and these ions will gain more energy and cause many more collisions to take place. The more collisions that take place the smaller the current will be and this causes the level of resistance to increase. After the 70cm mark the resistance was lower than expected. The resistance stopped being proportional to the length as it begun to curve at the end. It could not be due to the wire overheating because from that I would have expected the resistance to rise, and this is because the warmer the wire the more collisions that would have taken place. The more collisions that take place, the smaller the current and the higher the resistance would be. Since my graph begun to curve at the end I'm not totally sure that the resistance is proportional to the length. Maybe it is up to a point. Another reason why my graph curved toward the end could be human error. The current may not have been 0.6A for all the lengths. Evaluation I think that my investigation was successful but it could have been more accurate. Most of the points on my graph are near the line of best fit. I had one anomalous result which was the second reading for 70 cm. My reading was 1.83 which was way out so I did another test and now my new result for that reading is 1.36. This is most likely due to human error. I could have moved the slider on the resistor which would have changed the current and also my graph could not have been accurate from 70 "“ 90 cm. I may also have taken the length measurements wrong. Improvements I used a digital voltmeter which is accurate to +-0.01V and I used an analogue ammeter which is accurate to +-0.1A. If I had used a digital ammeter , which is has an accuracy of 0.01A then that would have given me more3 accurate results. I took three measurements where I could have taken five. If I had taken five measurements then I would have been able to have more points to plot on my graph. This would have helped me to see if I should have had a straight or curved line. The crocodile clips I used were all thick in diameter and all had different diameters. If I had to same slim diameter for each crocodile clip then I would have had a more accurate set of results. Further Work My investigation showed that up to 70cm my graph agreed with my prediction but after 70cm I'm not sure if the resistance is proportional to the length. I could have taken more readings on my graph after 70 cm and I could have taken measurements for every 2 cm after the 70cm point. I could also take my measurements up to 10 m to see if the resistance was proportional to the length for a longer length.   

Introduction What is electrical resistance? Electrical resistance is what limits the current inside a circuit. What effects resistance? • Length: The longer the length of a wire the higher the resistance level will be. • Diameter: The thicker the diameter of a wire the lower...

Words: 1783 View(s): 217 Comment(s): 0