A laboratory report reads: 'We measured a single strand of 32 SWG copper wire

PHYSICS · Multi-part · Fermi University Physics · Scientific Practice & Experimental Methods · Uncertainty in measurement · Records, communication and the epistemology of evidence

Measurement and Method, Ch Models, idealisation and what a measurement is evidence for

Problem

A laboratory report reads: 'We measured a single strand of 32 SWG copper wire, length (1.000±0.002) m(1.000 \pm 0.002)\,\mathrm{m}, diameter (0.274±0.003) mm(0.274 \pm 0.003)\,\mathrm{mm}, resistance (0.288±0.002) Ω(0.288 \pm 0.002)\,\Omega at a laboratory temperature of 21 °C21\,\text{°C}, and obtained ρ=(1.70±0.04)×10−8 Ω m\rho = (1.70 \pm 0.04)\times10^{-8}\,\Omega\,\mathrm{m}, all uncertainties standard uncertainties (k=1k=1). Since this agrees with the accepted value for copper, we conclude that copper has resistivity 1.70×10−8 Ω m1.70\times10^{-8}\,\Omega\,\mathrm{m} at all temperatures.' ((a)) Find the error in the concluding sentence. ((b)) Rewrite it as the bounded claim the measurement actually supports.

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