In this project I will be investigating how the length of Nichrome wire will affect the resistance. All length, cross section area, temperature and type of material are the factors that affect resistance. I will be keeping these variables constant besides length. To carry out this experiment I will set up a simple circuit and carry out a series of trials measuring voltage and current using different lengths of wire.Prediction:I predict that when the length of the Nichrome 32 wire is increased the resistance will also increase equally.
The resistance increases as the length increases because the electrons that are passing through the wire collide with the metal atoms of the wire. The more you increase the length of the wire, the more collisions there will be between the metal atoms and electrons. The collisions that occur produce heat energy which is caused by friction. I predict that if you double the length of the wire the resistance will also double.Fair Test:To make this a fair test I will keep certain variables the same, only changing the length of wire. The variables I will keep the same consist of the power supply so I don’t send more power to the electrons to go around, and temperature so that it doesn’t affect the resistance of the wire because increase of the temperature increases the resistance of the wire. I also want to keep the cross section area of the wire the same because as I increase the cross sectional area resistance will decrease.
These should stay the same to make sure that the experiment goes accordingly and resumes being a fair test. In this case I can carry out my experiment without having to worry about anything going wrong and it also allows my results to be more accurate.Equipment:* Ammeter* Voltmeter* Low Voltage Power Supply* Variable Resistor* Connecting Wires & Crocodile Clips* Wires Of Nichrome 32 (all the same diameter)Method:1. Set up a circuit as shown in the diagram above.2.
Measure a 100cm length of Nichrome 32 wire and connect it to the circuit.3. Set power supply to 6 volts DC and turn on.4.
Record the current and voltage and quickly turn off the power supply.5. Between each reading, allow the wire to cool and change the variable resistor.6. Repeat steps 3 – 5 two more times.
7. Change length of wire to 90cm, and repeat steps 3 – 6. Repeat the process for all the lengths as shown in the table.Health & Safety:Evaluation:Test Results (Preliminary Work):Length (cm)VoltageCurrentResistance (ohms)100.640.341.88201.110.313.58301.320.304.40401.690.266.54502.140.258.56602.470.2310.8702.630.2211.43803.060.2015.25903.100.1916.321003.150.2016.5789Test Results (1):Length (cm)VoltageCurrentResistance (ohms)102.092.600.80202.812.211.27303.121.591.96403.881.103.52504.050.974.17604.440.894.98704.690.746.33805.070.687.45905.200.618.521005.300.569.46Test Results (2):Length (cm)VoltageCurrentResistance (ohms)101.111.340.83201.531.291.18301.960.942.08402.360.743.18502.980.724.13603.540.854.16703.440.546.37803.910.537.37904.170.498.511003.990.439.50Test Results (3):Length (cm)VoltageCurrentResistance (ohms)100.941.020.92201.080.901.20301.540.742.08401.980.653.04502.500.604.16602.960.585.10702.900.466.30803.190.447.25903.610.458.021003.520.379.51Average Resistance:Length (cm)Average Resistance (ohms)100.80 + 0.83 + 0.92 ï¿½ 3 = 1.93201.27 + 1.18 + 1.20 ï¿½ 3 = 2.85301.96 + 2.08 + 2.08 ï¿½ 3 = 4.73403.52 + 3.18 + 3.04 ï¿½ 3 = 7.71504.17 + 4.13 + 4.16 ï¿½ 3 = 9.68604.98 + 4.16 + 5.10 ï¿½ 3 = 10.84706.33 + 6.37 + 6.30 ï¿½ 3 = 14.80807.45 + 7.37 + 7.25 ï¿½ 3 = 17.23908.52 + 8.51 + 8.02 ï¿½ 3 = 19.701009.46 + 9.50 + 9.51 ï¿½ 3 = 22.13