Investigating the Relationship Between the Length of a Wire and Its Resistance
Aim: To find the relationship between the length of a wire and it’s
resistance.
Planning: We conducted a preliminary experiment to help us conduct the
real experiment. In this preliminary experiment we aimed to find out
what thickness and type of wire would be suitable for the experiment,
and what range of lengths of wire and range of voltages and currents
would be suitable for measuring.
We discovered that at too great a voltages and too short a length, the
wire became very hot. One time it melted, in a way similar to a fuse,
because of the hot temperature, but this was only when we tested a
length of 2cm. We thought that these high temperatures might have an
effect on the resistance of the wire, but did not happen to a great
extent. This would have been a bad thing, however, as we were
conducting the experiment to find out solely the effect of the length
of wire on resistance, and not the temperature of the wire.
Below are the results of our preliminary experiment:
30cm
60cm
volts
current
current
1
0.65
0.37
2
1.43
0.79
3
2.09
1.12
4
2.65
1.42
5
3.52
1.87
6
4.03
2.2
7
4.97
2.6
8
5.16
2.84
9
6.29
3.23
10
6.64
3.65
11
7.91
4.15
12
9.84
4.76
I made the graphs below using these results.
[IMAGE][IMAGE]
The results from the preliminary experiment were not particuarily
accurate. I calculated the average resistance for each wire. This was
1.44ohms for 30cm and 2.69ohms for 60cm. This preliminary experiment
encouraged us to be as accurate as possible in the main experiment, in
The experiment was performed on one subject, a 20-year-old female gymnast that weighed approximately 58.6kg. First, she performed the test with the arm bike, which had 3 stages of 25Watts, 50W, and 75W all lasting 3min each. Before the end of
...red testing at Lectromec showed that contaminants, such as water, lavatory fluid, and metal shavings, can create a bridge that can allow energy to unintentionally transfer between wires with cracked or damaged insulation for as long as 25 minutes without tripping circuit breakers. Specifically, the totalizer gauge’s wires on TWA Flight 800 had been improperly soldered together and had subsequently cracked apart, providing another opportunity for an explosive short circuit. During examination of the gauge at Honeywell, it was determined that electrical energy would cross the crack in the solder between the connector pins when slightly more than 270 volts (less than is used in lighting circuits) was applied to one of the pins. Thus, a short circuit from a higher-voltage wire to any corouted FQIS wiring could result in excess energy being transferred to the CWT.
Volume's Effect on a Copper Sulphate Solution We are trying to find out if the current though a copper sulphate solutions volume is increased. To find this information out I shall perform an experiment using the following equipment; · 1 power pack · 1 beaker · 2 carbon rods for anode and cathode · 1 ammeter · 1 measuring cylinder · 2 crocodile clip wirers I shall also be using 60cm3 volume of copper sulphate in my preliminary results to decide upon the concentration of copper sulphate and the voltage I shall use. The following diagrams show the step by step process in which I will do my experiment; [IMAGE] [IMAGE] [IMAGE] [IMAGE] I will take 10 readings from 10cm3 to 100cm3. I will repeat my experiment to give my experiment a fair average. I will keep the power pack the beaker the carbon rods the crocodile clips the ammeter the concentration of copper sulphate and the measuring cylinder the same each time I do the experiment this experiment.
another accident if they raised the power all the way because of a problem with
equation V = IR. V - volts, I - current and R - resistance. I plotted
I also decided to use a wooden block to keep hold of the wire, because
The wire wouldn’t be burned or singed. That’s a result of oxidation. And there’s no oxygen in the air. There was likely a short afterall. But with the positive lead being unaffected, the power must have come from somewhere else. . . .”
0.000 7 63 106 55 74.7 1.245 9 70 135 90 98.3 1.638 11 85 135 70 96.8 1.613 [ IMAGE ] [ IMAGE ] Conclusion = = = =
F Another wire, or exact same properties (Nickel Chrome, thickness 34). mm and length 30cm) was placed on top of the previous wire, in the same position, both straight and flat. F. The power was turned on again and the same procedure was repeated. recording current and voltage at three points on the variable. resistor.
of the atoms, so if there are more or larger atoms then there must be
There fore less current passes through with the same voltage. Simply it is how hard it is for the electrons to pass through the wire. Temperature: When the metal wire is heated , more energy s given to the atoms, therefore they vibrate more. From this there is a greater chance of collisions with the electrons and they are impeded more, therefore less charge is passed by the electrons and the resulting current is reduced. This means while conducting the experiment the temperature of the wire must be kept constant to maintain a safe and fair test.
I have put my results in a table so that they will be easier to
In the experiment there are several possible ways of changing the electric current such as changing the voltage or the position of the electrodes within the electrolysis cell. However, it was found from preliminary work that the most effective way to change the current was to change the concentration of the acid solution. The preliminary work showed that the greater the concentration of the acid, the greater the current. Ohm's law states that R(resistance) =