What could cause data to linearize at a higher power than it should?

In summary, the conversation discusses a physics lab where the magnetic field produced by a magnet at different distances was measured and graphed against 1/r^3. However, the graph did not become linear until 1/r^5, which is not the expected result. Possible reasons for this deviation from the theoretical prediction were discussed, including the test setup, the type and size of the magnet, the range of measurements, and the physical dimensions of the Hall probe used. The conversation also touches on the removal of Earth's magnetic field bias and the need to keep distances short in relation to the length of the magnet. The term "linearize" was used to describe the data fitting well to a power law function, rather than being truly linear.
  • #1
djh101
160
5
For our physics lab we found the magnetic field produced by a magnet at different distances. When graphing the data, it was supposed to produce a linear graph when we plot the field strength against 1/r3. However, my graph doesn't become linear until 1/r5 (however, it does linearize quite nicely at this power). What are some possible reasons for the data linearizing at a higher power of r than it is supposed to?
 
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  • #2
djh101 said:
For our physics lab we found the magnetic field produced by a magnet at different distances. When graphing the data, it was supposed to produce a linear graph when we plot the field strength against 1/r3. However, my graph doesn't become linear until 1/r5 (however, it does linearize quite nicely at this power). What are some possible reasons for the data linearizing at a higher power of r than it is supposed to?

Can you describe your test setup and instrumentation? A photo or drawing would help too.

What makes you think it should follow 1/r3? That may only be for some idealized setups...
 
  • #3
We measured the magnetic field of a permanent magnet with a Hall probe and took measurements at different distances from the magnet. We are given that B is proportional to the inverse of r cubed. I would understand if the data was a little off and didn't fit exactly, but it linearizes almost perfectly, just not at the right power of 1/r. I'm really just looking for a general explanation as to why a particular set of data might linearize at a different power than theoretically predicted (in this case B ∝ 1/r^3 theoretically but B ∝ 1/r^6 experimentally).
 
  • #4
djh101 said:
We measured the magnetic field of a permanent magnet with a Hall probe and took measurements at different distances from the magnet. We are given that B is proportional to the inverse of r cubed. I would understand if the data was a little off and didn't fit exactly, but it linearizes almost perfectly, just not at the right power of 1/r. I'm really just looking for a general explanation as to why a particular set of data might linearize at a different power than theoretically predicted (in this case B ∝ 1/r^3 theoretically but B ∝ 1/r^6 experimentally).

Was it a bar magnet, a horseshoe magnet, or some other shape? How big was it? Over what range did you make the measurements? What were the physical dimensions of the Hall probe? how did you remove the bias of the Earth's magnetic field? Can you post your data?
 
  • #5
Did you keep the distances short (eg much less than the length of the bar magnet)?
 
  • #6
What do you mean "linearize to 1/r^5"? (A power law is not linear unless the exponent is 1.) Did you mean that your data were a good fit to that function?
 

Related to What could cause data to linearize at a higher power than it should?

1. What is the definition of "linearization" in terms of data?

Linearization refers to the process of transforming non-linear data into a linear relationship. This is often done to make the data easier to analyze and interpret.

2. What does it mean for data to "linearize at a higher power"?

When data linearizes at a higher power, it means that the relationship between the independent and dependent variables is not linear, but instead follows a higher power function such as quadratic, cubic, or exponential.

3. What are some common causes of data linearizing at a higher power than expected?

There are several potential causes for this phenomenon, including measurement errors, outliers, missing data points, or the presence of a non-linear relationship between the variables.

4. How can one determine if the data is linearizing at a higher power?

This can be determined by visually inspecting the data plot and looking for a curved pattern or by conducting statistical tests such as the coefficient of determination (R-squared) or the p-value of a regression analysis.

5. Can data linearize at a higher power even if the variables are not related?

Yes, it is possible for two variables to have a non-linear relationship, even if they are not related at all. This can occur due to random chance or external factors that are not accounted for in the data analysis.

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