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PHYS 195: Waves and Fields

Interference by soap film

Spring 2019

Laissez les bonnes ondes rouler! (Let the good waves roll!)

- from the livingston, LA LIGO Observatory (at one time)

Instructor: Seth Major, smajor, 4919, G052
Office Hours:

Tuesday 2 - ~5:00 PM

Mondays 2 - 4



MWF 10:00-10:50 AM Science Center G041



Halliday, Resnick, Walker, Fundamentals of Physics Extended, 10th Edition (same as Phys 190)

John Taylor, An Introduction to Error Analysis

Kleppner & Kolenkow and Simmons reading (on blackboard)



Thursday afternoons 1:00 - ~4:00 PM with Viva Horowitz in G034

Friday afternoons 1:00 - ~4:00 PM with Adam Lark in G034



  • The final had an average of 82% and a standard deviation of 8%. Have a great summer!
  • Here is the 2019 grade calculator.


Course Info:

course syllabus (pdf)


  • Wolfram Alpha (launches a new tab):
  • Clicker questions from lecture.
  • We discussed lots of material this semester. Here is a six page (is it possible?) review.
  • On Soap film intensities. A movie of our demo. Here is a link to much, much more on colors.
  • The video of an interference experiment done at Hitachi by Tonomura
  • More slit patterns on hyperphysics.
  • Two-slit interference and diffraction intensity applet.
  • Single slit interference plots and double slit plots.
  • Here is the Phet simulation of interference.
  • Snell's law waves, without the reflected wave, with the reflected wave.
  • The Phet lens demonstrator.
  • The electromagnetic spectrum.
  • An animation of an e&m plane wave. Wave of an accelerating charge. Wave of an oscillating dipole.
  • light! The details if you want to see them - these are OPTIONAL notes on the derivation of the wave equation of electromagnetic fields
  • The interval of time between Earth's magnetic field reversals is on the order of 250,000 years (an average). The reversal is not periodic. NOVA has a brief description. Here's the page of one of the authors on a 1995 paper describing numerical simulations of the mechanism that generates Earth's B-field.
  • Notes for the Biot-Savart calculation of the magentic field on axis of a solenoid.
  • Motor kits have been distributed. These details include a description of what it is all about and a description of a motor design.
  • Here's a way to fix the silly positive/negative charge conventions. Too bad it is so difficult!
  • Phet Electric Hockey!
  • The Doppler shift for light is used in astronomy. Here is an illustration and info on red and blue shifts. The effect is one technique for finding extra solar planets. More on the use of the relativistic frequency (Doppler) shift to find an exoplanet near 51 Pegasus. This technique is also used to explore the structure of the universe. A page summarizing much more detail on this.
  • The Doppler effect at a train station and as a costume on Big Bang Theory.
  • Here is the Phet simulation of interference.
  • A reconstruction of the black hole merger event that led to the gravitational wave discovery in 2015. The founders of the experiment won the 2017 Nobel Prize in Physics.
  • More on waves in spacetime: LIGO, interviews with gravity wave folks, and movies of numerical simulations of black hole binary systems.
  • For more on ocean waves try this link.
  • Animations of different types of wave motions.
  • Here's the derivation of the equation of motion for sound.
  • Here's the page from which you can launch the PhET Fourier series demo. Requires Java.
  • There's a Chladni plate picture in the banner of this web page. Wikipedia has more on Ernst and his plates. Here's a page of his notebooks. Of course, YouTube has Chladni plate videos and there's a 2D flaming (!) demonstration shown in this video.
  • Our derivation for transverse waves on a string.
  • The Citicorp Center in NYC and the Taipei 101 Tower have tuned mass dampers. A book by Kohn, Katz, and Robertson has a schematic of the Citicorp Center mass. The building is 279 m high and has a period of around 6.5 s.
  • Here's a pendulum in the Taipei 101 Tower. For more specifics see this article and "Wind and Earthquake Resistant Buildings", some of which is on google books.
  • Here's the PhET wave simulation.
  • Here's the PhET normal mode simulation. (Requires Flash.)
  • The results are in! The 2019 measurement for g on the Hill is g = 9.84 +- 0.08 m/s^2! (This agrees with the previous average of 9.815 m/s^2. Given the variation in measurements I used the standard deviation of your results for the error.)
  • The masses on springs videos: 1 and 2.
  • A resonator exhibit at the Exploratorium.
  • A video of a wine glass orchestra or harp.
  • You can see more of the Tacoma Narrows bridge in this video.There's a 2006 American Journal of Physics article by Green and Unruh on a more careful modeling of the Tacoma Narrows bridge. (This link is to the arXiv where many physics papers are available to read without charge.) Last year APS News published a piece on this and the authors reminded us that the original accident report pointed out the non-resonant behavior of the bridge.
  • Here is the Phet simulator on resonance.
  • A XKCD comic on resonance.
  • In class on Friday, February 8 we went through the `late time' or `steady state' solution of driven, damped, harmonic motion. Here are the notes (pdf) for the `brute force' approach of plugging the trial solution and working through the algebra.
  • Millennium Bridge oscillation video.
  • For a review of rotational dynamics see Chapter 10 of HRW.
  • Galileo may have timed the swinging of the chandeliers in the Pisa cathedral. This one appears to be one of the "modern" ones installed in 1587.
  • Here is the PhET spring mass-on-a-spring demo. Enjoy!


Labs (pdf):

Lab Syllabus
The Phys 190-5 Uncertainties in a nutshell and guide to Taylor
The Anatomy of a Notebook
Lab 1: Simple Oscillation
Lab 2: Moving Away from Simple Oscillation with a Pendulum
Lab 3: Measuring g with a pendulum
Lab 4: Resonance
Lab 5: Standing Waves (8.9 MB)
Lab 6: Speed of Sound
Lab 7: Coulomb's Law
Lab 8: LRC Circuits and relative phase
Lab 9: B-field mapping
Lab 10: The q v x B force and the electron's charge to mass ratio
Lab 11: Snell's Law
Lab 12: Interference and Diffraction


Last modified 19 May 2019

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