Aim: The aim of this experiment to find the relationship between length of wire and the resistance it will create. Variable: Here are the list of variables in this investigation… Control Variables: Voltage of circuit Type of wire Thickness / Cross sectional area Components in circuit Amount of connecting wires Temperature Input Variables: Length of wire Outcome Variables: Current Resistance Voltage cross wire Prediction (Basic): My prediction is that the greater the length of the wire, the greater the resistance.
What Is Resistance: Resistance is when electricity is being slowed down by particles whilst flowing through a material (e. g. metal) What Is A Metal: Metal is a solid subtance that has the following properties:- High melting & boiling points Conducts heat & electricity Hard & dense Malleable Ductile Scientist believe that metal atoms or ions are held together by a sea of electrons (see below) Why can metals conduct electricity: Metal atoms have outer electrons which are not tied to any one atom. These electrons can move freely within the structure of a metal.
When more electrons are pushed into a piece of metal (by an electric current for example) the electrons just flow through the metal in between the metal atoms. The electric current flowing through the wire is a flow of electrons. Electrons have a negative charge. There are no such free electrons in covalent or ionic solids, so electrons can’t flow through them – they are non-conductors. Aim: The aim of this experiment to find the relationship between length of wire and the resistance it will create. Diagram: Method: The method for this experiment is as follows:- First gather all the equipmen Set the wire up Mark the wire in 10mm gaps.
Set up circuit Put one croc clip at end of wire other on marked part of wire Take reading then move marked croc clip up Repeat until finished Put Result in results table Results: First Set: Milimetres (Length of Wire) Voltage AmpsSecond Set: Milimetres (Length of Wire) Voltage AmpsPreliminary Conclusion: These two sets of results show that every 10mm the voltage get higher and the amps get lower the reason the amps column is in negative is because the ammeter was connected the wrong way. Diagram: Apparatus List: The list of equipment we use is as follows:- Bulb A Plank of Wood Main Method: First of all you gather all your apparatus. Then attach the wire using cellotape making sure it is tight as possible.
Mark ten millimetre gaps on the plank using a ruler and marking it with a pen until you get to one hundred and fifty millimetres. After you’ve done that set up the circuit as shown in the diagram making sure the Power Pack is on two to four volts (the easy way to set the circuit up is to do it without the volt or ammeter then add it on when finished). Attach the crocodile clip to the wire then place on the very end of the wire and the other on the ten millimetre mark which you have marked out. Then take the reading of the volts and amps and write it in a results table. Continue until finished then work out the resistance (see analysis).
Results: Milimetres (Length of Wire) Voltage Amps Resistance raph: Analysis: I processed my results by : Average : I worked out my average by adding my results together then dividing by two. E. g. N/a Volts Amps 100mm Resistance: I worked out the resistance by using ohms law which is R =V/I which translated is resistance = voltage divided b current. E. g. Volts Amps 1. 04 0. 075 R = 1. 04 / 0. 075 = 13. 86 Conclusion: Like my prediction the resistance increased as the length of the wire increase. The graph is consistent and is basically a y=x graph show if you double the length of the wire the resistance doubles. Evaluation: In the end the experiment was a success and was exactly as I predicted and was very simple to set up and use the equipment.
My graph have no anomalous results because they all fit the line of best fit which is very pleasing. I think my result are reliable because the two sets I did in my preliminary and the final set were all extremely close. I controlled the fixed variable by keeping the voltage the same for all the tests and giving it a break in between the result to keep the temperature the same. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.