Modern Optics Lab Introductory Meeting

Contact Information Gernot Laicher South Physics 410 (801) 585-5553 gernot@physics.utah.edu TAs: Bijaya Thapa (Tuesday and Wednesday Sections) bijayathapa104@yahoo.com Jieying (Amaya) Mao (Thursday and Friday Sections) jieying.mao@utah.edu Website: http://www.physics.utah.edu/~gernot/Modern Optics/Modern Optics.html Modern Optics Lab

Lab Format Lab descriptions will be on our website (pdf files). Before the lab: Read through lab description. Try to understand the principle of the experiment and the data evaluation methods. Think about the format of your lab report. Labs are done individually, not in groups. A short introduction/overview to the lab activity is usually given at the beginning of the lab. Lab report is written as much as possible during the lab. Submission deadline is 1 week after lab completion. 9 labs (11 lab sessions) are planned over the course of the class (may vary). Modern Optics Lab

Grading in Modern Optics Quizzes: 15% Midterm Exams: 20% Final Exam: 30% Lab Grade: 35% Your lab score is obtained as follows: 90%: Grade received for lab reports 10%: General Lab conduct Displayed interest/diligence in lab activity Ability to answer questions asked by TA Cleanliness of workspace at the end of the lab Creativity Punctuality There is a 10% grade deduction for every day the lab report is late. Modern Optics Lab

Writing the Lab Report Keep in mind the main purpose of a lab report which is a written record of the purpose of the lab activity, methods and techniques - experimentally and mathematically, raw data as measured and their uncertainties, data analysis (e.g., computations) including error propagation, conclusions derived from your data analysis. “Say what needs to be said” as efficiently, concise, and clear as possible – we are not writing novels. A picture is worth a thousand words: Include a sketch of the apparatus when describing the methods. Label what’s on the sketch. Don’t forget units! Don’t submit messy lab reports in which the TA needs to “fish for information”. Modern Optics Lab

Lab Report Grading General guideline (may vary depending on lab activity and TA): 20% Purpose, Methods, Techniques ….. 30% Raw Data Record 20% Data Analysis 10% Error calculation Measurement uncertainties in raw data Propagation of error 20% General appearance and organization Legible ? Looks organized ? Easy to follow ? Modern Optics Lab

Missing a lab due to Illness, etc. Arrange with the TA a way to make up the missed lab activity. If possible, in another section the same week. Alternatively a time outside the regular lab hours may be arranged between you and TA. Worst case: We may waive a lab and base your grade on the remaining average. Modern Optics Lab

Significant Figures and Uncertainty Report uncertainties (error) in measurements to one significant digit Make sure the position of the least significant digit of the measured value agrees with that of the uncertainty. Modern Optics Lab

Estimating and Reporting Uncertainty Estimation of uncertainty from a single measurement due to measuring device (e.g., ability to read out a scale) Uncertainty in repeated measurements and averaging (averaging 5 or more measurements to get mean)  calculate standard deviation of the mean Modern Optics Lab

Error Propagation Calculating the error in the final result based on the error in the measured quantity can be done in several ways. Calculate the “high” and “low” possible outcome based on using extreme values of input data (x+dx and x-dx). Doing a “proper” error calculation. Modern Optics Lab

“High/Low” Method Suppose you measure a quantity and it’s uncertainty ….and you want to calculate the value of a function f(x) and the uncertainty df of the function f(x) at the point x=xo Modern Optics Lab

Modern Optics Lab

Modern Optics Lab

General Error Propagation Method Modern Optics Lab

Example Modern Optics Lab

Example Modern Optics Lab

Example using “High/Low” Method Method overestimates error somewhat Modern Optics Lab