- Level: International Baccalaureate
- Subject: Physics
- Word count: 1766
Experiment to calculate the diameter of a piece of nichrome wire from its electrical resistance by varying the length of the wire
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Introduction
IB Group 4 Internal Assessment ChemistryBiologyPhysics
Name: Date(s): 14/2/12
Candidate Number: 00-3072-074 Session: Level: HL
Investigation Title: _______THE DIAMETER OF NICHROME WIRE______________
Internal Assessment Marking Form
Criterion | Required Aspects | Level | ||
Complete (2) | Partial (1) | Not at All (0) | ||
Data Collection and Processing | Records appropriate quantitative and associated qualitative raw data, including units and uncertainties where relevant. | Records appropriate quantitative and associated qualitative raw data, but with some mistakes or omissions. | Does not record any appropriate quantitative raw data or raw data is incomprehensible. | 2 |
Aspect 1 – Recording Raw Data | ||||
Aspect 2 – Processing Raw Data | Processes the quantitative raw data correctly. | Processes quantitative raw data, but with some mistakes and / or omissions. | No processing of quantitative raw data is carried out or major mistakes are made in processing. | 2 |
Aspect 3 – Presenting Processed Data | Presents processed data appropriately and, where relevant, includes errors and uncertainties. | Presents processed data appropriately, but with some mistakes and / or omissions. | Presents processed data inappropriately or incomprehensibly. | 2 |
Conclusion and Evaluation | States a conclusion, with justification, based on a reasonable interpretation of the data. | States a conclusion based on a reasonable interpretation of the data. | States no conclusion or the conclusion is based on an unreasonable interpretation of the data. | 2 |
Aspect 1 – Concluding | ||||
Aspect 2 – Evaluating Procedure(s) | Evaluates weaknesses and limitations. | Identifies some weaknesses and limitations, but the evaluation is weak or missing. | Identifies irrelevant weaknesses and limitations. | 1 |
Aspect 3 – Improving the Investigation | Suggests realistic improvements in respect of identified weaknesses and limitations. | Suggests only superficial improvements. | Suggests unrealistic improvements. | 2 |
Middle
Trial 5
37.3
±0.1
2.5
2.6
2.4
2.6
2.5
74.6
±0.2
4.4
4.5
4.6
4.5
4.6
111.9
±0.3
6.4
6.4
6.5
6.3
6.3
149.2
±0.4
8.6
8.4
8.5
8.4
8.5
186.5
±0.5
10.6
10.5
10.4
10.6
10.5
Sample calculations:
Sample calculation 1. Calculating the length and uncertainty of Nichrome wire using error propagation: The length of one knob to the opposite knob (1 fold) was measured, shown in fig 1 above. It was assumed that this length was the same length between each opposite knobs (fig 1). The measured length was found to be 37.3cm with the ruler having an uncertainty of ±0.1. Therefore, the uncertainty increases by a magnitude of ±0.1 and the length increases by 37.3cm for each length trial. Calculations show in sample calculations 1 below. 1 fold = 37.2 ±0.1cm 2 folds = (37.2 ±0.1cm) + (37.2 ±0.1cm) = 74.6 ±0.2cm 3 folds = (37.2 ±0.1cm) + (37.2 ±0.1cm) + (37.2 ±0.1cm) = 111.9 ±0.3cm |
Sample calculation 2. Converting length from cm to m: Example using the trial from the length of 37.3cm: |
Sample calculation 3. Calculating the average resistance: Example using the trial from the length of 37.3cm: Answer has to have the same number of decimal places as uncertainty ∴ Average resistance |
Sample calculation 4. Calculating the uncertainty of the average resistance using maximum deviation: The highest and lowest value of the resistance is subtracted from the average result. The highest magnitude of the result will be used as the uncertainty. |
Conclusion
The composition of the nichrome wire varies and also the electrical resistivity. Therefore, the median was assumed to be the electrical resistivity. The actual electricity may have been different from the assumed value which affects the calculations of determining the diameter.
By finding the percent composition of the nichrome wire, the electrical resistivity may have been estimated which will improve the accuracy of the experiment instead of assuming that the value is the median.
Bibliography
(n.d.). Science Supplies Australia , 12.
WireTron-Inc. (n.d.). Nichrome 80 & Other Resistance Alloys - Technical Data & Properties. Retrieved February 13, 2012, from Wiretron: http://www.wiretron.com/nicrdat.html
[a]0.02
[b]Give your information a descriptive title to help the reader understand what you’re presenting
[c]These are good graphs. Just try to give all your tables/graphs good, descriptive titles.
[d]Explain why you made can claim this is so. (it’s true, just explain your evidence)
[e]good
[f]You need to consider the resistance of the cable leads you used to connect to the multimeter. These are probably your greatest source of systematic error.
[g]Your recommendations are straight-forward and effective for the errors that you have identified.
[h]good
[i]good
[j]Give your information a descriptive title to help the reader understand what you’re presenting
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Here's what a teacher thought of this essay
A well written and structured essay with extremely good choice of quotations to support the writer's points. Areas such as how Juliet reflects the position of many women in Shakespeare's time yet defies such expectations to be the obedient and dutiful daughter could be developed further.
Marked by teacher Stephen Evans 21/02/2013