resistance of a wire
Aim The aim of this coursework is to investigate how the length of a constantan (18SWG) wire affects the resistance in a circuit. Preliminary Testing Before I can conduct the experiment I need to investigate further into what I am going to do for the investigation. By doing the preliminary testing I can find the easiest and the best method of doing the experiment. I can also make any alterations to the investigation. The first problem I had was the material that I was going to use as a conductor. I decided to choose constantan wire because it is cheap and it is easily found. Another reason for choosing this was because the resistivity was not that small or large to work with. The table below shows the possible materials we could have used. Material Resistivity/m Silver Copper Aluminium Iron Constantan Mercury Germanium Alumina Pyrex Fused Quartz The next decision I had to make was the type of constantan wire we could have used. I chose to use 18 SWG because its diameter was not to small and not to large. I had other alternatives as well the table below shows this. S.W.G 6 8 20 22 24 26 28 30 32 34 36 38 40 Diameter (mm) .62 .25 0.91 0.71 0.56 0.46 0.38 0.32 0.27 0.23 0.19 0.15 0.12 Now that I have decided on my apparatus I now need to work on the factors. There are many factors that could be taken in to account. I
Resistance of a Wire
Background scientific knowledge Electricity Electricity is the movement of charge (electrons) around a circuit. The charge flows throw conductors which allow the electrons to pass through. An object which does not allow electrons to pass through is an insulator. Conductors intended to have resistance are called resistors (symbol ) Voltage- given the symbol V, measured in volts using a voltmeter Current- given the symbol I, measured in Amperes using an ammeter Metallic structure diagram Resistance Resistance is the ability to prevent or resist the flow of electrical current. Resistance occurs in an electrical circuit because of a collision between electrons and atoms, which slows the electrons down and converts some of their KE to heat energy. Resistance is measured in Ohms (?). Diagram Arrow shows direction of electron movement through the wire. Equation Factors which affect resistance Length of wire - this is being investigated Thickness of a wire - in a thin wire there are more possible paths for the electrons to pass through, therefore more electrons can flow through at one time, this increases the current which increases the resistance. Material of wire - wires of different densities will block more or less electrons Temperature - the vibration of warm molecules makes them more likely to collide with electrons, and resistance
Resistance of a Wire
Will changing the length and type of wire affect the resistance? What is my aim of this project: To set up an electric circuit to measure the resistance of the wire. What are my Variables: * Thickness of the wire * Length of the wire * Type of wire Equipment I plan to use: * Wires * Volt meter * Ammeter * Crocodile clips * Power pack * Ruler * Copper coil * Nichrome coil What is resistance? Resistance is measured in (OHMS). It is the hindrance to the flow of charge. Why did we get resistance? An electric current flows when electrons move through a conductor. The electrons that are moving can collide with the atoms of the conductor. This then means that it is more difficult for the current to flow, which causes resistance. On the other hand, electrons have a collision with atoms more often in a longer wire than they do in a short one, however, a thin wire has fewer electrons to carry the current than a thick wire. In a thin wire there is less space, but more resistance and in a long wire there is more space, yet less resistance. The flow of electrons: Hypothesis: Before I do my experiment I predict that the resistance in the wire will increase as the length of the wire increases. I also predict that if the resistance in the wire increases, then the thickness of the wire will decrease. My diagram of my circuit: For my first investigation task I will be
Resistance of a Wire
Resistance of a Wire Coursework Planing (Final) Independent variable: -Length of wire (cm) Dependent variable; -Dial voltage (4 volts) -Material of wire (Nickel chrome) -Width of wire (28 SWG) Aim: My aim is to see how the length of the wire affects the resistance. Prediction & Hypothesis: My prediction is that when the length of wire increases, the resistance will also increase. Same as when the length of the wire doubles, the resistance will also doubles because Resistance is caused when the electrons collide with the ions. Therefore when it is doubled, the electrons will collide with twice as many ions, so the resistance will also double. Introduction: Measuring equipments I have chosen a digital voltmeter and an ammeter as my measuring equipments because it shows the voltage and current in decimal points, so I know that my results can be more accurate. Range and intervals My length of wire will increase 10 cm every time and I will make 6 readings. I will repeat all my reading twice and get the average to make sure that they are the most accurate results that I can get. Results Plan The heading for my results table will be 'dial voltage', 'actual voltage', 'length of wire', 'current', and 'resistance'. To ensure a fair test I will make sure that the dependent variable will be the same through out the experiment. Safety I will assure that when I conduct
Resistance of a wire
INTRODUCTION - An electrical circuit was mounted using a power supply, an ammeter, a voltmeter and a resistor (wire). The voltage and current were worked out for different lengths of the wire using the ammeter (for the current) and the voltmeter (for the voltage). Using the voltage and current recordings, the resistances were calculated for each of the lengths. AIM - To investigate the correlation between the length and the resistance of a wire. DIAGRAM - PICTURE - HYPOTHESIS - I predict that the longer the wire, the greater the resistance. This is because the electrons have to move in a longer distance, making the opposition (resistance) of conductor to the current greater. RESULTS - Tables of results to show the resistance of the wire for different lengths. TRIAL 1 Length (cm) Voltage (V) Current (A) Resistance (?) 00 6,4 7,2 0,888888889 90 6,3 7,7 0,818181818 80 6,2 8,7 0,712643678 70 6,3 0,2 0,617647059 60 6,1 1,5 0,530434783 50 6,1 3,7 0,445255474 40 6,15 6,8 0,366071429 30 5,83 21,8 0,267431193 20 5,71 29,3 0,194880546 TRIAL 2 Length (cm) Voltage (V) Current (A) Resistance (?) 00 6,4 7,3 0,876712329 90 6,4 8,1 0,790123457 80 6,67 9 0,741111111 70 6,28 9,9 0,634343434 60 6,32 1,9 0,531092437 50 6,28 4,2 0,442253521 40 6,12 7,3 0,353757225 30 6,09 22,4 0,271875 20 5,9 32,9
Rate of reaction
Chemistry Coursework William Lavelle-Bowden Candidate number: 7108 Aims: To investigate rates of reaction. Introduction: I have been given different reactants to choose from as a suitable reaction to change variables is needed to investigate our rates of reaction. The reactants I have at my disposal are: -Hydrochloric Acid (HCl) -Magnesium Ribbon (Mg) -Calcium Carbonate Chips (CaCo3) -Sodium Thiosulfate (Na2S2O3) From these reactants I had a number of reactions to choose from, such as: ) Hydrochloric Acid + Sodium Thiosulfate --> Sodium Chloride + Sulphur Dioxide + Sulphur + Water (HCl+ Na2S2O3 --> Nacl +NaO2 + H2O) 2) Hydrochloric Acid + Magnesium --> Magnesium Chloride + Hydrogen (HCl + Mg --> MgCl2 + H2) 3) Hydrochloric Acid + Calcium Carbonate --> Calcium Chloride + Carbon Dioxide + Water (HCl + CaCo3 --> CaCl2 + CO2 + H2O) From this I had to choose one reaction to start changing variables. The variables I have to use are: -Temperature -Pressure -Surface Area -Catalyst -Concentration As we did not have sufficient laboratory equipment we were not able to asses variables such as pressure and surface area. A catalyst could also not be used as these were forbidden in school. Strategy Deciding which reactants to use Experiment One For the first experiment I chose to use calcium carbonate chips and hydrochloric acid. I used 50 ml of
Rate of Reaction Investigation
Rate of Reaction Investigation: Introduction: The rate of reaction measures how fast a chemical reaction occurs. You can change the rate of reaction in different ways such as changing the concentration of either the Sodium Thiosulphate Solution or the hydrochloric acid. Temperature can also be used to change the rate of reaction as the hotter the temperature is the faster the reaction occurs. I could also use a catalyst to provide a lower energy route for the reaction to occur. This would cause the speed of reaction to increase as it would increase the collisions. Although in this case I am not using a catalyst in my experiment so this means that I have controlled this key factor. In my experiment I am not using surface area as a facto but I do know that the small the particle the faster the reaction. This only applies when using solids in an experiment. Preliminary Work: Results Table These are the preliminary results. This was when we were experimenting and practising how to do the method. Whilst doing this we determined which dilution of STS and the acid worked the best and came up with reliable and accurate times. These below are the five best dilutions we came up with: Vol of Hydrochloric acid (cm³) Vol of Sodium Thiosulphate Solution (cm³) Vol of Water (cm³) Concentration (g/l) 0 50 0 40 2 0 25 25 20 3 5 50 5 40 4 5 25 5 20 5 2.5 2.5
Rate of Reaction - Sodium Thiosulphate and Hydrochloric Acid
Sodium Thiosulphate Coursework Introduction I have been asked to investigate the effects different factors such as concentration and temperature have on the rate of reaction The rate of reaction is the loss rate of a reactant or the rate of creation of a product during a chemical reaction and it can be measured by dividing one by the time taken for the reaction be completed. Collision Theory states that an increase in concentration, temperature, surface area and the use of a catalyst in a reaction will either increase the rate of reaction by increasing the rate of collision between reactant particles, increase the success rate of collisions between the reactants or both of these reactions, there is also another factor which effects the rate of reaction, but is only applicable in gasses, that factor being pressure. I have chosen to investigate the effects of Concentration on rate of reaction, as it is the most accurately achievable while still challenging factor to change. Method: Equipment- x conical flask 2x 50ml measuring cylinder x 10ml measuring cylinder x pipette Sodium Thiosulphate Hydrochloric acid Water Stop clock Safety goggles Plain paper with a black cross on it. Add 10ml of HCL to a conical flask, by All procedures will be undertaken with safety goggles on. After assembling all of the equipment I will pour as close to 10 ml of hydrochloric acid
Is Cloning Ethical?
Is Cloning Ethical? For the past few years the political and ethical argument for and against the process of cloning has been raging. So is cloning really unethical? Is it against human rights? Before we decide this we must first understand exactly what cloning is. Cloning can be done using a few different processes, which will be later mentioned. It is the creation of an embryo which is a genetically identical copy of another human (1). There are three main types of cloning. The first is known as Embryo Cloning. This is a technique, the same as the natural process of making identical twins or triplets, where cells are taken from a fertilised egg and encouraged to develop into twins or triplets with identical DNA (2). The second is known as Reproductive or Adult DNA Cloning. This method is used to produce an animal with identical DNA to an existing animal. DNA from an ovum is removed and is replaced by DNA from an adult animal cell. It is then implanted into the womb of a surrogate mother and develops into an animal. This kind of cloning is illegal in many countries as, based on studies performed on animals, it could cause genetic defects. It is considered by many to be unethical and dangerous, however Dr Severino Aninori claims to have used this procedure to initiate pregnancy (2) Biomedical Cloning, better known as Therapeutic cloning is the third process. In the
Animal Testing
Is Animal Testing/Research Necessary for Advancing in Medicine? Introduction: Animal testing involves using non-human animals for scientific procedures. Animal research can be used for a number of things such as developing new drugs to improve health, learning about animals and the human body, aiding scientific advances and ensuring other products do not harm humans. Vaccinations against diseases like polio, rabies, measles, mumps and rubella were developed because they were tested on animals. Also the development of open-heart surgery and organ transplants depended on operations done on animals. In 2006 approximately two million animals were used in procedures. Animals that are normally used in tests and experiments include: rats, mice, rabbits, monkeys, guinea-pigs, cats, dogs, fish, birds, pigs, horse, sheep and hamsters. This pie chart shows the types of animals used in procedures. A large proportion of experiments are conducted on mice. (1) Those who are extremely against animal testing (animal rights activists) would refer to it as 'vivisection'. This means the 'cutting up of animals'. They refer to animal testing being morally wrong and cruel. However this is just one view, others are not so against animal testing. Others may believe that animal testing is necessary for some purposes for example medicinal purposes yet not for beauty products. Methods of
