Introduction to Physics 340 Amartya Dutta

Modern Physics (but is it really, though?) e/m experiment - first done in 1897 by JJ Thomson Stefan-Boltzmann experiment – experimentally in 1879 by J Stefan and derived in 1884 theoretically by L Boltzmann Photoelectric effect – Discovery by H Hertz in 1887 Compton scattering – observed first in 1923 by AH Compton

Objectives To repeat some very important experiments which ultimately led to the formulation of quantum mechanics To gain experience with various experimental techniques, and analyse and synthesize non-trivial experimental data To get an idea of writing a lab report based on the experimental work performed

General lab procedures/practices Notebook – bound, quadrille lined (coarsely gridded graph paper) computation notebook Avery Dennison No. 43-648 or equivalent Every page of notebook should be numbered; writing should be legible, clear, in ink and in serial order No blanks except for table of contents Additional loose information must be permanently affixed No erasures, white-outs or scribble-outs

General lab procedures/practices Table of contents on first few pages Dates on all pages; no writing on a page with an earlier date Units with every dimensioned quantity Associate results with corresponding uncertainties and significant errors

General lab procedures/practices Come prepared to lab Refer to books read regarding experiments, including lab handouts Outline goal of the experiment Outline basic theory; deriving equations preferable to copying Outline experimental setup and procedures Cutting schematics and diagrams from lab handouts allowed, but drawing preferred

General lab procedures/practices In Lab: Collect some preliminary data and analyze before proceeding In Lab: Plot an initial graph to make sure things are correct; it need not be perfect but should be included in notebook Graph should be re plotted more perfectly by hand or on computer during final analysis

General lab procedures/practices Tabulate results, if possible Show data analysis by at least one detailed calculation, showing what is being done and why Diary function End-of-class check Final write-up

Final Write-up Summarize everything done in not more than 2 pages Include best value for experimentally determined quantity and best assessment for uncertainty on the value Comparison with “accepted” values Can have references to notebook pages where more details can be found

What not to do Spending no time writing in notebook prior to experiment No derivation of important equations in notebook Entries in notebook dated one week apart Paste graphs or spreadsheets on one page No error quote in final value

What not to do No final write-up No identification numbers on graphs and data tables Copying data from loose data sheets into notebook

Notebook grading Formatting Prelab: Theory, Procedure, Data Postlab: Analysis, Final Write-Up

Notebook grading

Notebook grading 12% e/m lab report 20% first lab notebook reading (Stefan-Boltzmann) 20% Photoelectric lab report 20% Second notebook reading (Compton effect) 20% Final experiment lab report 8% attendance

Graphs Should have titles and units on each axis Too small symbols should not be used to represent data points in graph Barring a few exceptions, should have error bars Should explain meaning/origin of line through data

Graphs Unacceptable

Graphs Acceptable

Graphs

Formal Lab report Should represent scientific papers ready for submission Encouraged to read a few papers in the American Journal of Physics Should have a format as given in lab manual Will be judged on: 1) quality of scientific content and 2 2) quality and clarity of writing Use of spreadsheets/graphing programs

How to get an A Follow the do’s and don’ts of lab Submit your lab report by the deadline Keep your work organized, legible and original

Emergency Response To report an emergency, call 911. To obtain updates regarding an ongoing emergency, sign up for Purdue Alert text messages, view www.purdue.edu/ea. There are nearly 300 Emergency Telephones outdoors across campus and in parking garages that connect directly to the PUPD. If you feel threatened or need help, push the button and you will be connected immediately. If we hear a fire alarm during class we will immediately suspend class, evacuate the building, and proceed outdoors. Do not use the elevator. If we are notified during class of a Shelter in Place requirement for a tornado warning, we will suspend class and shelter in [the basement]. If we are notified during class of a Shelter in Place requirement for a hazardous materials release, or a civil disturbance, including a shooting or other use of weapons, we will suspend class and shelter in the classroom, shutting the door and turning off the lights.