Experimental College Physics With an Introduction to Data Analysis Dr. Alain Brizard Saint Michael’s College Dr. Alain Brizard Saint Michael’s College Dr. Alain Brizard Saint Michael’s College

Outline The Nature of Experimental Physics Measurements and their Uncertainties Zen and The Art of Significant Figures Techniques of Data Analysis The Structure of a Laboratory Report

The Nature of Experimental Physics A Physical law is an experimental statement of fact. A physical theory is a well-tested model. Purpose of a physical experiment: –Explore natural phenomena –Support or Challenge a physical theory

Theory versus Experiment Example: Electron g-factor

Measurements and their Uncertainties Measurements are made with instruments of finite precision. Uncertainties are due to random or systematic errors. –Random errors are introduced by UNBIASED measurements. –Systematic errors are introduced by BIASED measurements.

Uncertainty versus Error Precision versus Accuracy

Zen and The Art of Significant Figures Experimental result: g_exp   _g –Proper result:(12.57  0.03) m/s –Improper results:(12.6  0.03) m/s (12.57  0.1) m/s

Techniques of Data Analysis Experimental results are calculated by Linear Regression with Excel. –Data Collection & Tabulation within Excel –Graphical Display of Experimental Data –Calculation of Mean Values and their Standard Deviations by Linear Regression Inclusion of Experimental Results with Proper Significant Digits

Excel Spreadsheet

Sample Excel Spreadsheet Example I: Hubble’s Law

The Structure of a Laboratory Report Title of the Experiment Qualitative/Quantitative Aims of the Experiment Theory Procedure & Materials Data Tables Data Analysis and Graphs: Annotated Excel Spreadsheet Table of Results & Discussion Conclusions