How The Length Of A Wire Is Affected By The Resistance
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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.

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I plan to see... I plan to see if the body size of an animal affects its heat loss. I am going to do this by using three glass beakers with various amounts of boiling water in them. I will then see which beaker looses its heat the fastest or the slowest. Prediction I predict that the smaller the animal the faster that it will loose its body heat so I predict the smaller beaker will loose its heat the fastest and the largest one will loose its heat the slowest. The science I predict this because for example if you have a drop of boiling water and a jug of boiling water the drop of boiling water will cool down the quickest. I have also predicted this because the wild animals in the cold adapt to their environment by the size of their bodies and shape. I will be focusing on the size. E.g. polar bears live in cold weather so they are big to reduce heat loss. Apparatus "¢ 3 glass beakers "¢ kettle "¢ thermometer "¢ 3 timers Safe test I will make sure that my experiment is safe by "“ "¢ Making sure that I handle the boiling water carefully. "¢ Making sure that the water doesn't spill near any electricity or on the floor "¢ Make sure that I do not smash anything Fair test I will make sure that my experiment is fair by "“ "¢ Having the water at the same temperature at the start of the experiment. "¢ Don't not insulate them "¢ Do the same to each one. E.g. if I stir one I will have to stir the others. Range and extent "¢ 20 minutes timing "¢ Beakers "“ 100ml, 200ml, 300,ml Variables There will be 100ml in one beaker, 200ml in another and 300ml in another. This will not affect my investigation because these variables are significant to my experiment. Method Firstly I will set up my equipment data logger, water and computer. The beakers will be set out with the right amount in each one and the temperature readers will be placed in each beaker. And then I will press start on the computer and the data loggers will record my results on a graph and also on a table so I can spot exactly where any anomalies occur. This will be done for 20 minutes and when it is finished reading I will print out the required information that I need. Conclusion From doing this experiment have found out that the smaller the animal the quicker that it looses its heat and the larger the animal the slower it looses its heat. My prediction was proved correct. The water temperatures started near enough at the same temperature and they have all dropped in Celsius but the 100ml dropped even more. Here I how they dropped: Start Finish Range 100ml 89.4 52.5 39.9 200ml 91.2 59.2 32 300ml 91.2 61.9 29.9 In the table you can clearly see how my prediction was correct however I would have expected more of a difference between the 200ml and the 300ml. The bigger the animal the slower it looses its heat and the smaller the animal the quicker it looses its heat. Animals in colder conditions are mostly large because the condition they live in is cold. If you look at the graph you can see how my results dropped. Evaluation I don't think that my experiment was very successful even though my prediction was correct. I don't think it was very successful because of the actual experiment. Here are my reasons: "¢ The 100ml beaker didn't start off at the same temperature of the other two. "¢ There are two anomalies in my results where the temperature had dropped dramatically I think that this has happened because maybe the temperature reader came out of the water for a few seconds. That is the only explanation that it could possibly be. Apart from the anomalies, my results do support my conclusion. If I was to repeat this investigation then I would stick the data loggers down to the beaker so that they do not come out of the water. I would also repeat the experiment 3 times to be more accurate and I would also include a 400ml and a 50ml amount in the experiment. By doing this I would have found out more information and made my results more accurate. If I had more time then I would research the sizes of animals in different climates. This will have made me surer about my conclusion.   

I plan to see if the body size of an animal affects its heat loss. I am going to do this by using three glass beakers with various amounts of boiling water in them. I will then see which beaker looses its heat the fastest or the slowest....

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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...

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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...

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