PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Records, communication and the epistemology of evidence · Records, communication and the epistemology of evidence
Measurement and Method, Ch Writing the result, and the integrity of the data behind it
Problem
Two researchers, P and Q, measure the deflection of a cantilever beam under five different end loads to find the beam's Young's modulus E from the standard deflection formula. Researcher P set up the apparatus, applied each load and read the deflection with a micrometer for all five loads; P has read the final report and is willing to answer for all of it. Researcher Q wrote the weighted least-squares script that turns the five (load, deflection) points into E, carried out the calculation, and is willing to take responsibility for the analysis, but did not re-check P's raw micrometer readings herself, having trusted P's logging of them. Fitting all five loads gives E=(178±22)GPa with χν2=5.4. The logbook records, timed during the run: "load 4: micrometer zero found to have shifted by 0.3mm before this reading; zero reset and reading redone for load 5 only." Excluding load 4, the fit gives E=(198±6)GPa with χν2=0.9. The submitted report states in its results section only: "Results based on the four consistent trials, E=(198±6)GPa." The method section says five loads were used. Eight months later, a marker asks why the figure shows only four points.
((a)) Name the three records that would let P and Q answer the marker's question, and state what each must show in this case.
((b)) Judge whether the results-section sentence meets the disclosure standard, and rewrite it so that it does, using the numbers above.
((c)) Apply the two conditions for authorship to P and Q. Say what Q should do about the raw readings she did not check herself before her willingness to take responsibility can be honoured, and decide whether both should be listed as authors.