Measurement of Young Modulus
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Measurement of the Young modules
Aim:
The aim of this experiment is to measure the Young modules of copper wire.
Method:
- Clamp the copper wire across the bench using the G clamp and the wooden blocks.
- Pull the wire until it is straight enough and put a standard weight to the lower end.
- Use the blue tag to act as a marker for the convenience of the measurement.
- Make sure the two ends are fully clamped between the blocks.
- Measure the length of the wire(L) from the clamped beginning to the end and the diameter of the wire using the micrometer.
- Increase the weight in small steps
- Record the position that the blue tag moved(△L) after each weight is added.
- Record the weight(m) when the wire extended.
- Keeping adding the weight until the wire broke and record the breaking point.
- Repeat the experiment for 3 times.
- Area of the wire is calculated by A=(0.5*d)^2
- The force of the weight(F) needed to be calculated by the formulae F=mg.
- Strain and stress of the wire need to be obtained by using the formula strain=△L/L, stress=F/A
- Results were recorded in the results table.
- Plot a graph of stress against strain.
- Calculate the Young modules(E) from the gradient of the graph.
Result:
Length:2020mm
Area:2.34*10^—3
Mass /g | Force /N | Extension /mm | Strain | Stress /Pa |
150 | 1.47 | 1 | 4.95*10^—4 | 628.21 |
250 | 2.45 | 2 | 9.9*10^—4 | 1047.01 |
350 | 3.43 | 4 | 1.98*10^—3 | 1465.81 |
700 | 6.86 | 5 | 2.48*10^—3 | 2931.62 |
900 | 8.82 | 6 | 2.97*10^—3 | 3769.23 |
1100 | 10.78 | 7.5 | 3.71*10^—3 | 4606.84 |
1300 | 12.74 | 10 | 4.95*10^—3 | 5444.44 |
1500 | 14.7 | 15 | 7.43*10^—3 | 6282.05 |
1750 | 16.66 | 43 | 2.13*10^—2 | 7119.66 |
Observation:
- It is difficult to record the position of the wire.
- The size of the wire makes it harder to measure.
Conclusion:
Our value for young’s module is 1.04*10^10
Evaluation: