Investigating how the length of a wire affects its resistance
Physics Coursework Investigating how the length of a wire affects its resistance Sean Connolly 12M I have decided for my coursework that I will investigate how length affects the resistance of a wire. Background information on resistance In 1826, George Ohm discovered that: The current flowing in a metal is proportional to the Potential difference across it providing the temperature remains constant. He then developed a formula: - Resistance (R) = Voltage (V) ? Current (I) Resistance is a measure of how easily the electrons can move through a metal. Therefore a low resistance means that the electrons can move more easily. Aim In my investigation I shall try to see if the length of a piece of wire affects its resistance. Prediction I predict that the length of wire will affect its resistance. I am making this prediction because all metal s contain electrons in their outer shell. The larger the surface area of the piece of wire, the more positive ions there are present within the wire. The more positive ions there are contained in the wire, that the more chance the negative ions will collide with them and the electrons will be slowed down and some f its energy will be picked up by the ions. If this happens often enough then the current will be reduced and the metal will get hotter. This heat will cause the resistance to increase. An increased resistance means
Investigating LDRs
Investigating LDRs A light dependent resistor is a resister that depends on the amount of light shining on it. Introduction I will be investigating how much of a current that flows through the resistor depends on the amount of light that is shining on the LDR. Planning My prediction for this coursework is that the more the further that I move the LDR from the light the weaker the current will be on the milliammeter. Equipment The equipment that I will be using will be: Milliammter LDR Cell (battery) Meter Ruler Lamp Power Pack 4 Leads Component Clip Method Step by Step I will be working in a pair. I will set up a circuit that will measure the amount of light that will shin on the LDR.I will be taking 8 reading of different distances. We will be repeating each concentration three times so all together we will have 24 sets of results. This will make it a fair test. I will be changing the amount of light going to the LDR by moving the LDR further away from the light that means that I will be changing the distance. I will by measuring the current that flows thought the circuit by using a milliammeter. To get a reading the light has to shin on the LDR (semi conductor) this will let free the electrons, which lets the current flow throw the circuit to the milliammeter I will make this a fair test by repeating each distance three times and this will also make the
Investigate the variation of the resistance of a thermistor with different temperatures.
Instrumentation Task Sensor Project Introduction For this experiment I am going to investigate the variation of the resistance of a thermistor with different temperatures. The resistance will be tested at every 5 degrees, with a range from 90 C down to 5 C, and these results will be recorded. After recording the results, the experiment will be repeated at a total of 3 times, this is so we can get an average that should be correct and accurate. Plan: Sensor circuit The following below, are what are needed for me to complete my task: * One thermistor * Digital multi-meter with a setting to read resistance in Ohms to 2 decimal places The sensor circuit's purpose is to sense the change in temperature in a domestic water tank. For example it will be able to sense and recognise when the water is very close to boiling point and if it has dropped to close to freezing point. If it gets to hot, the sensor would cause the heater to be switched off. If it gets too cold, the sensor would cause the heater to be switched on, so avoiding the risk of burst pipes due to freezing. On separate circuits there will be many thermistors flooded in the water at different points, so we are able to find an overall temperature in the tank. This is due to convection, which causes the water to be hottest at the top and coldest at the bottom. Variables The variables are as follows: Independent
Physics coursework
Physics coursework Jaypal Sandhu 12c Mr.Rugg How does different temperatures affect the resistance of a metal wire/thermistor. Aim (preliminary): The preliminary aim of my coursework was to measure what affect different temperatures have on the change in resistance of a copper wire. Apparatus: * Distilled water * Heat proof mat * Tri pod * Bunsen burner * Copper wire * 5v power pack * Electrical wires * Crocodile clips * Thermometer * 100? resistor Diagram: In theory this was a good experiment however in practice it was not. Whilst conducting the experiment I realise that from the temperature changing from 0 degrees to 100 degrees there was only a small change of 0.01v. I tried with a different resistor but still had no luck. There was not enough change for me to conduct a worthwhile experiment. I tried to use a higher current on the power pack but still the voltage never changed of the copper wire and as a higher current was used I ad to press the reset button as the power pack continued to reset. Therefore I concluded that using copper wire to conduct this experiment was not appropriate as it's resistively was too high to be affected by small or even large changes in temperature. Instead of using a metal I decided to use a thermistor as it can be subjected to different temperatures and I can expect some results Aim: The aim of my investigation is to see
Physics Coursework - Factors that affect the resistance of brine-soaked paper
Physics Coursework - Factors that affect the resistance of brine-soaked paper AIM I am trying to find out how different factors affect the resistance of brine-soaked paper. I will choose one factor and then do a series of experiments to try to find out how this factor affects the resistance. I have chosen to change the length of the paper. PREDICTION I think that when I increase the length of the paper, the resistance will also increase. When I increase the length, I predict that the resistance will also increase by the same amount making the relationship directly proportional. This is what I think the graph of final results will look like: I think this will happen because the resistance will drop when the length of the paper is reduced. This is because the ions have a shorter distance to travel through the liquid on the paper when it is a short piece of brine-soaked paper and therefore have less time and less in the paper to collide with the anything. Therefore when the paper is a long piece, the more ions there is, the more collisions that will be made and so the higher the resistance. The ions will need to work harder and will collide with more particles so the resistance will keep increasing every time the paper length is increased and therefore this will happen when double the paper length, the resistance will also double from before. PLAN In this investigation,
Organisational Change.
Organisational Change The one true test of an organisation is its ability to change to the seemingly random and turbulent business environment. A traditionalist view is to see the organisation as a living organism, and that it needs to evolve in order to ensure continued survival. Common focal points for change include: * Structure * Strategy * Culture * Technology * Job design The foundations of OC begin in looking at how change in the workplace can affect the individual, and how they can impact on the workplace. One of the key points in this area of research is with regards to Resistance to change, which is not restricted necessarily to any particular level of staff. Most emphasis on change results in problems that a manager may face, but considerations should also be given to behavioural patterns that may manifest as a result of resistance. Kanter (1983) observed that in many occurrences the behaviour of managers causes a suppressing effect, rather an encouraging one. O'Day (1978) identified a series of practices whereby managers may seek to discourage subordinates with proposition of change. He called these intimidation rituals, and they include (in order of execution); Nullification, Isolation, Defamation and Expulsion. Some of the reasons for opposition may include: * Innate dislike of change * Institutionalised practices * Threat to interests * Response
What is resistance?
PLANNING What is resistance? Electricity is conducted through a conductor; in this case it is conducted through a wire through means of free electrons. The number of free electrons depends on the material. The more free electrons the better the conductor is. For example, gold has more free electrons than iron therefore gold is the better conductor. The greater the resistance tin a circuit the less current that flows. A variable resistor is able to control the amount of current that flows through a circuit. Increasing the length of wire will increase the resistance. Ohms Law is when the voltage is directly proportional to the current. This means that when the voltage is doubled the current is doubled as well and if the voltage was cut in half the current would cut in half as well. The symbols used in ohms law are V for volts, R for resistance, measured in ohms, and I for the current, measured in amps. The equation V=IR is used to work out the Voltage; I=V/R is used to calculate the current; and R=V/I to calculate the resistance. Predictions I think that the longer the wire is the higher the resistance will be. This is because the longer the wire the more times the free electrons will collide with other free electrons and the particles and impurities that make up the metal. Fair Test To make this experiment fair I will have to make sure that: * The length of
