This tells me that the voltage measures the amount of energy used up in getting each coulomb of charge through the wire. The units of volts are the same as joules per coulomb. Therefore, Ohms law says the more resistance means more energy used to pass through the wire. Resistance is a measure of how much energy is needed to push the current through something. The electrons carrying the charge are trying to move through the wire, but the wire is full of atoms that keep colliding in the way and making the electrons use more energy.
Preliminary Method
In this preliminary experiment, I will use different lengths of wires to measure their resistance. The main idea of doing the preliminary experiment was to find a suitable current number to put the power supply on. I also wanted to do this experiment to familiarise myself further with the method; if I had any problems I could correct them there and then. This would mean I would obtain precise and reliable results in my main experiment when investigating the connection between the length of the wire and the resistance of the wire. wwda daw esdadas ayda daba nda kcda dauk;
First, the circuit was set up as shown below. I had to be careful in connecting circuit, because the Voltmeter had to be placed in parallel and the ammeter, which had to be placed in series. Draw up a rough table onto a piece of paper with the appropriate headings. The wire was cut to just over 50cm so the crocodile clips could attach onto the wire, making the results more accurate. Stretch out the wire onto the bench and measure with a metre rule. The power supply was put on 2V and the gradually increased the 4V, to find a suitable current for my main method. The slider on the resistor was moved to allow me to do five repeats. I decided to go down in ten centimetre gaps, as it would allow me to lot a graph of resistance against length with a range of fie readings. wwbg bgw esbgbgs aybg bgba nbg kcbg bguk. wwca caw escacas ayca caba nca kcca cauk.
Results
As shown below there is only a range of five readings, which start to show a pattern, that the best fit line is directly proportional. To see if this trend carries on, I will widen my main experiment and use a 100cm length of wire, I will also take the readings every 5cm and not 10cm. From my experimentation with the power supply, I have decided to keep it at 4V, as I do not need the wire length to go lower than 10cm.
Length (cm) Current (Amps, A ) Voltage (Volts, ) Resistance (Ohms, ) Average resistance (Ohms, )
Main Experiment
Prediction
I predict that if the length increases then the resistance will also increase in proportional to the length. I think this because the longer the wire the more atoms and so the more likely the electrons are going to collide with the atoms. Therefore, if the length is doubled the resistance should also double. This is because if the length is doubled the number of atoms will also double resulting in twice the number of collisions slowing the electrons down and increasing the resistance. My graph should show that the Length is directly proportional to the resistance. kbfy19wrV Visit essaybank dg co dg uk dg for more dg Do not dg redistribute kbfy19wrV
If the length of the wire is only half the length of the wire on the same type of wire, there should be half the number of collisions between the electrons and the atoms.
If the wire is twice as long, there should be twice the number of atoms, resulting in twice as many collisions and a predicted doubling of the resistance.
Safety
Handle the power supply carefully.
I am going to only use a voltage of four volts so the wire will not burn.
Be careful when touching the wire, as it may be hot.
Start on the lowest current, so the wire then will not melt or burn instantly.
Be careful when the wire is connected, as it will get hot.
Be careful when cutting the wire.
Make sure the mains to the power supply is switched off when removing the wire from the circuit to be measured. wwef efw esefefs ayef efba nef kcef efuk.
Apparatus -Power Supply, Ammeter,Voltmeter,Just over 100cm of E26 Wire,Meter Rule,Two Crocodile Clips,Connecting Wires.
Factors which must stay constant to keep the experiment a fair test
The power supply must stay on 4V,
The wire must be the same thickness,
The surrounding temperature must be constant,
The equipment should be kept the same,
The edge of the crocodile clips should be at the edges measured length.
The Variable factor
The factor that I am going to vary is the length of the E26 wire.
Circuit diagram
Method
The circuit was set up as shown above. A table was drawn out and the results were recorded. To improve the accuracy, compared to my preliminary results for my main wwdd ddw esdddds aydd ddba ndd kcdd dduk;
Experiment, I have decided to set up the circuit with the metre rule selotaped to the bench. This will make it easier and more precise as I will not have to keep on holding the wire then putting the crocodile clips on. I have chosen to use a meter ruler because the lengths that I will be measuring are to big for a smaller ruler and the meter ruler can be accurate to +1mm. Make sure that the metre rule is actually one metre long and not one or two centimetres shorter. Next, move the crocodile clips down five centimetres rather than ten (as done in preliminary) each time to record the results. Use the E26 wire as it will also be easier to measure any change in resistance. To collect the data for my graph I have chosen to take a range 20 of lengths. I have chosen a range of 20 as to plot an accurate graph, I will need at 20 points to mark on the graph if I want to make precise and reliable results, to see if there are any patterns and trends. I have also chosen to take five repeats at each length and then take an average, to get reliable results. The lengths that I have chosen are as follows: 100cm, 95cm, 90cm, 85cm and going down in fives to 10cm length of wire. I have chosen these lengths because they are easily measured by the meter ruler and give a good range of results.
As my preliminary results start to show a pattern in the readings (Resistance is directly proportional to length) to expand on my experiment and to see if this pattern continues, I am going to try the above lengths.
Analysis
In my prediction, I stated that:
If the length increases than the resistance will also increase in direct proportion to the length.
From my graph on the previous page, I can see that the resistance of the wire is directly proportional to the length of the wire. I know this because the Line of Best Fit is a straight line through the origin showing that if the length of the wire is increased then the resistance of the wire will also increase in proportion to each other. The line of best fit is a straight and it goes though (0,0) if there is no length, there is no resistance proving that the resistance of the wire is directly proportional to the length of the wire. This proves my prediction right. I can work out the gradient of this line by dividing the Resistance by the length. So, 1.75/55=0.0318
The length of the wire affects the resistance of the wire because the number of atoms in the wire increases or decreases as the length of the wire increases or decreases in proportion.
The resistance of a wire depends on the number of collisions the electrons have with the atoms of the material, so if there is a larger number of atoms there winl be a larger number of collisions that will increase the resistance of the wire. If a length of a wire contains a certain number of atoms when that length is increased, the number of atoms will also increase. from www.essaybank.co.uk
If the wire is half the length of a certain wire, it would have has half the number of atoms, this means that the electrons will collide with the atoms half the amount of times. In addition, if the length of the wire was trebled or quadrupled, then the resistance would also treble or quadruple. This is indicated on my graph, with the length being 100cm and the resistance being 3.25 Ohms. This in theory would mean that at 50cm there would be a resistance of 1.63 Ohms. From the graph it is easy to tell that the theory is correct and therefore my results reliable. From my results table and graph, I can see that my results that I collected are quite reliable and accurate. I know this because my results table shows a few, individual anomalous results; the anomalous results are at lengths 95cm and 100cm. All the other points are extremely close to the line indicating that my results are accurate. I think that my results are suitable to confirm my prediction and support a conclusion. I know this because outside resources (Textbooks and Britannica) say that ‘the length increases in direct proportion to the resistance.´
Evaluation
In the Analysis and the graph I have shown two main anomalous points, this means that there must have been a slight error in my experiment. As the wire, length is bigger at these points I found it harder to stretch it out and consequently, measure it accurately. Although the graph is overall accurate and the results precise it is easy to see, the anomalous averages plotted because they do not all lie along the same best-fit line. The graph shows that my results are reliable as there are only two main anomalous points, (which are easily accounted for) to improve the reliability of my results, I could do more repeats in doing this my average would be more reliable. wwbe bew esbebes aybe beba nbe kcbe beuk. wwcg cgw escgcgs aycg cgba ncg kccg cguk.
As I increased the wire length, the wire became hotter and gave off heat. This could explain why the anomalous results are at the top of my graph, 100cm and 95cm. I think one of the reasons why my experiment is quite accurate is because I tried to measure the wire as accurately as possible. The metre rule was selotaped onto the workbench. The wire was stretched until it was nearly in a straight line so a bit was overlapping at each end. As the metre rule was curved and worn down at the corners it was slightly hard to see where 0cm was. Finally, the inside edge of the crocodile clips were placed at the appropriate point. I still however would like to make the measuring more accurate
During my experiment, I have noticed several modifications I could make to improve on the Investigation if I was to repeat it.
The first of these modifications would be the circuit that I would use. To be more accurate with my results I would place the Metre rule directly under the wire, so therefore it would be measured easier and therefore making the lengths more precise.
Instead of connecting the voltmeter to the main circuit, I would connect it to the wire that is being tested. I would do this so that the voltmeter is measuring the voltage of just the wire being tested and not the wires of the main circuit as well.
To also improve on my results I could use a new or higher quality digital voltmeter. The next modification I would make would be to use pointers instead of crocodile clips to attach to the wire; I would do this because pointers would be more accurate. The pointers would be more accurate because the tips have a much smaller area than the crocodile clips giving a more accurate measurement of the length of wire. I would also use a newer metre rule. The graph shows that my results are reliable as there are only two anomalous points, to improve the reliability of my results, I could also have repeated the same lengths of wire more times. Although the wire is an E26 wire, the thickness of it may vary by a small amount and maybe helping to cause the anomalous results. Sometimes the ammeters flicked between a decimal point, I maybe could have thought it was the wrong number and therefore would have ended up with the wrong average resistance. In the experiment, I did not control the room temperature but instead just assumed it was keep constant throughout my experiment; this could have made the wire get hotter and therefore making my experiment not as accurate. In future experiments I would control this variable factor and make it a constant factor. I would do this, as it would be an unfair test if there were two known variables As well as making these modifications, I could also expand on my investigation by testing the same wire but different widths of that wire. I would do this if I had more time to complete it. I think the circuit and method used was quite suitable although I would make the modifications above to improve my results. If I did this experiment again I would defiantly use top quality equipment, I would probably control the temperature and use pointers instead of crocodile clips. After changing those few things, there is not really much difference to how I would do the experiment again.
The Task of this investigation is to find out the factors that affect the resistance of a variety of electrical conductors.
This will be done by performing experiments that try and investigate different proposed factors and to see whether they affect the resistance.
There are many factors that are known to affect the resistance of an object; it is determined by the nature of the substance of which it is composed, known as the resistivity, the dimensions of the object, and the temperature. The dimensions of the object include the surface area of the wire conductor and the length of the conductor. The factors that can be investigated in Physics are those known as quantative results or those that have continuos data such as length. The Factors that I will be investigating will be the type of material, the surface area of the wire and the length. The reason temperature is not being investigated is that it is a difficult factor to measure because it Is hard to measure the temperature within a wire. Temperature affects the wire so that the experiment does not become fair. To eliminate this we must perform a preliminary experiment to show what is the range of readings we must perform the experiment within; this range will be so that it does not be affected by heat. essaybank.co.uk wwff ffw esffffs ayff ffba nff kcff ffuk.
Knowledge that I already have is Ohms law and how to measure resistance using a voltmeter and an ammeter. Ohm's law states that the amount of current flowing in a circuit made up of pure resistances is directly proportional to the electromotive force impressed on the circuit and inversely proportional to the total resistance of the circuit. The law is usually expressed by the formula I = E/R, where I is the current in amperes, E is the electromotive force in volts, and R is the resistance in ohms. This enables us to work out the resistance using the current and Voltage. wwga gaw esgagas ayga gaba nga kcga gauk.
R=V/I.
The other piece of background knowledge is to measure resistance in a circuit using a voltmeter and ammeter. This is done by: V/I=Resistance fIc3EZ6P Visit essaybank gf co gf uk gf for more gf Do not gf redistribute fIc3EZ6P
In this experiment I expect that, as there are three different wires to be investigated when it comes to Material of the conductor. These are constantan, Copper, Nickel Chromium and Manganese. These are used as wires in industry for some of their characteristics such as high conductivity (Copper, which is also very ductile) and the wires can be as small as to have a diameter of 0.025mm. I expect that the longer the wire is the more the resistance, I also think that the resistance is directly proportional to the length. This prediction is backed up by the fact that when there is a long wire, the electricity has to travel and further distance and therefore collides with many more protons as it passes through and may be slowed down because the electrons have been deflected. My Prediction is that the length of the wire will be directly proportional to the resistance of the wire. I also expect the cross section also to be directly proportional to the resistance of the wire. I think that according to each individual wire, the resistance will be different, to gain a helpful prediction, some more background information must be achieved. wwcb cbw escbcbs aycb cbba ncb kccb cbuk: wwec ecw esececs ayec ecba nec kcec ecuk.
As the red electrons travel from the negative end to the positive end, they are attracted by the opposite force Protons (blue) with then the electrons collide with and then continue the journey, The Protons are also vibrating, as the heat increases so does the amount of vibration of the protons. I think that as the surface area of a wire increases so does the resistance. This is because of the same reason that there are more Protons to collide with. Some metals have different resistances, this means that some metals such as copper are excellent conductors whilst other such as plastic are terrible. wweg egw esegegs ayeg egba neg kceg eguk.
This coursework from ()
Reproduction or retransmission in whole or in part expressly prohibited
wwfb fbw esfbfbs ayfb fbba nfb kcfb fbuk:
I will make this experiment fair by performing investigation on each variable one at a time as not to get the variable mixed up. For a suitable set of results I will investigate how the different materials affect the resistance, in this experiment I shall have wire of the same length, surface are but I will have 4 different materials. For the length and surface area, I shall keep all other variable the same except of those that I am investigating. I shall also have to control the temperature in order to stop it from interfering with the investigation and changing the resistance. How I will perform the experiment is by, taking a wire of a certain Gauge and of 50 cm length (keeping all variables except the variable being investigated constant) Then use the power supply, voltmeter, ammeter, crocodile clips, wires and measuring devices (ruler). With these instruments, I will set up the diagram shown. After performing a preliminary experiment using a piece of wire and connecting the circuit together, I will see the power supply that is best suited for the experiment. After performing this experiment, after many wires had burnt, I decided that the best reading would be 4 volts. from www.essaybank.co.uk wwdd ddw esdddds aydd ddba ndd kcdd dduk.
I will take as many different measurements as possible so that there can be a good spread of results so that I am able to arrive at a good conclusion. To increase the accuracy of my results I will perform repeats for all my experiments so that the average will make a highly accurate results table. wwgc gcw esgcgcs aygc gcba ngc kcgc gcuk.
Here are some examples tables for the Length factor:
Constantan:
Length of Wire: cm Voltmeter Reading: Volts Ammeter Reading: amps Resistance: ohms
5
10
15
20
25
30
35
40
45
50
This will investigate the value of varying the length of the wire. The repeat results will be produced in a graph similar to this.
I will need a ruler, different metals and an instrument to measure the surface area of the wire. I will also need a voltmeter and an ammeter.
The equipment will be set up in the following manner as shown in the circuit diagram so that I can measure the voltage readings and ammeter readings for each length and wire. I will vary the Wire by placing a crocodile clip at different lengths down the wire in order to vary the lengths. VpCh from VpCh essay VpCh bank VpCh co VpCh uk
I will use the results of the investigation to answer the question by placing the results into a chart and then transferring the information onto a graph so that is easy to interpret. We can see that if my prediction was correct because we can see that there is a direct proportionality between the factors and the resistance. wwad adw esadads ayad adba nad kcad aduk:
Other work and preliminary work that I have done that will help me in this experiment is that
Made available free online by www.essaybank.co.uk. Reproduction in whole or in part expressly prohibited. © EssayBank.Co.Uk - .
For over 14,000 GCSE, A-Level and University Essays and courseworks visit
Other Coursework and Essays in this Category
-
- Physics Investigation Of Resistance Aim: to investigate how the elect ...
-
- The four factors that affect the resistance of a piece of wire: Length ...
-
- Introduction : Resistance is a force which opposes the flow of an ele ...
-
- Investigating the Resistance Of A Wire When The Diameter Of ...
-
- Before starting my coursework I have decided to chose a factor that wi ...
-
- Resistance of a Wire Task To investigate how the resistance of ...
-
- Aim I am going to be studying the resistance of wire. The purpose of t ...
-
- Introduction In this piece of coursework, I have been set the t ...
-
- Planning Aims and hypotheses This investigation is designed to look ...
-
- The Task of this investigation is to find out the factors that affect ...
-
- Planning Variables Length of wire: The length of a wire ...
-
- Planning - The resistance of a wire can be affected by certain facto ...
-
- The resistance of a wire depends on certain factors. Investigate the e ...
-
- Investigation into factors affecting the resistance of a wire Aim: Du ...
-
- Aim I am going to be studying the resistance of wire. The purpose of t ...
-
- "GCSE Physics Resistance of a Wire" Extended Title: "Investigation of ...
-
- The Task of this investigation is to find out the factors that affect ...
-
- The dependant variable is the resistance of the wire. The Key Variab ...
-
- Brief How is resistance of a wire affected by the length of a wire. H ...
-
- A. Planning Plan of the method to be used: - The resistivity of nich ...
-
- Aim: - To find out what factors affect the resistance of a wire (be ...
-
- Current and Resistance Aim: Investigate how the length of a wire aff ...
-
- Physics Coursework Investigation I intend to invest ...
-
- Aim: The aim of this is to investigate how the length of a wire affec ...
-
- Resistance of a Wire Investigation I am investigating how resistan ...
-
- Physics for you, Keith Johnson, and Physics revision guide by Richard ...
-
- Background Knowledge RESISTANCE Electrons move more easi ...
-
- Introduction Electric charge on an object is often called ...
-
- I am conducting this experiment to determine how a certain variable af ...
-
- ` We have a lamp of resistance 6 ohm, which will light w ...
-
- Factors Of Change Temp Length Cross Section Metal CURRENT - ...
-
- Introduction Electric charge on an object is often called static elec ...
-
- Factors Of Change Temp Length Cross Section Metal CURRENT - is the ...
-
- Factors Affecting the Resistance of Wire Introduction ...
-
- Science Investigation Investigation: ...