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Modern Physics

Demonstrating Polarized Interference

Roberta Tevlin, OAPT Editor, Teacher Danforth CTI
Rolly Meisel, OAPT Photographer

The interference of light is a very important concept in senior high school physics and has been for a long time. The polarization of light used to be a minor topic but has become more and more important over the last couple of decades because of its use in LCD screens and 3-D movies and because it is possible to get a cheap class set of polarized filters. This article describes a demonstration that combines polarization and interference. Read More...

Building a Michelson Interferometer, Part II

Richard Taylor, Merivale High School, Ottawa
(see also

In the last episode, I had received the main parts of a Michelson Interferometer (the mirrors) and had roughly set them up using Lego stands. In the past couple of weeks I have been working on making a more stable and adjustable platform for this interferometer. Read More...

REVIEW: Three Short Videos of the Double Slit Experiment

Roberta Tevlin, OAPT Editor, Teacher Danforth CTI

The double-slit experiment is one of the strongest pieces of evidence for the wave nature of light and it is also the best place to start to explore the key concepts of quantum physics. By this point, most teachers in Ontario are familiar with the great, free teaching resource from The Perimeter Institute of Theoretical called The Challenge of Quantum Reality. If you haven’t got yours yet, you should! Three short, on-line videos are now available as an addition to the resource. Read More...

Building a Michelson Interferometer

Richard Taylor, Merivale High School, Ottawa
(see also

My school has had a Michelson Interferometer for many years, and I always show it to my grade 12 students to help explain the Michelson-Morley experiment - the one that showed that the speed of light does not depend on the motion of the observer. I showed this interferometer to some other Physics teachers on the February 2016 PD day in Ottawa. They were very interested and wanted to show their students. So I thought I would find out if I could build a similar and very inexpensive interferometer. Read More...

Great Annual Opportunity at the Canadian Light Source in Saskatoon

Saara Naudts, OAPT Contest Editor, Physics Teacher North Park SS
Each December, teachers from across Canada have an opportunity to experience what goes on at one of Canada’s biggest research facilities. After an easy application process, including a generous amount of available funding and very helpful communication with Tracy Walker the CLS outreach coordinator; I and several other teachers flew out to Saskatoon to visit the synchrotron December 5-7, 2015. Read More...

Let Your Grade 12 Students Leave High School Thinking Modern Physics is Fun…

Sandy Evans, Northview Heights Secondary School

I used to have our Grade 12 Physics students write a research paper on a Modern Physics topic; however this year I decided to let them do something more creative. They ended up really having fun with the assignment and it was A LOT more fun to mark than 50 essays. They were told about this assignment and their Rube Goldberg Build assignment at the beginning of the semester but the Modern Physics Creative Piece was not due until one week before exams. Read More...

Gravity Waves: The Fast Track to the Best Resources

Margaret Scora, Mhona Russell, James Ball and Roberta Tevlin

The announcement that LIGO has detected gravity waves may have you scrambling to answer your student’s questions. This news connects to many topics in high school physics including waves and vibrations, interference of light, changing models of science and the analysis of data - especially the problem of signal to noise ratios. Many teaching resources have been suggested (listed at the bottom) and these have been examined to select which are the most useful for high school physics teachers. The selected videos are well-scaffolded and paced. They make good use of animations, physical models and analogies and showed a wide diversity in the people interviewed. Demos and activities were selected which require minimal prep time and cost for the teacher and which provide active-learning experiences for the student. Read More...

An Experiment Involving Heisenberg’s Uncertainty Principle

James Ball, OAPT Membership Chair, Physics Teacher, John F. Ross C.V.I.

The Heisenberg Uncertainty Principle is a very abstract concept for most high school students and teachers. This lab activity is a simple variation of a single slit diffraction experiment. It clearly shows that defining the location of a photon (by passing it through a slit) increases our uncertainty about its momentum. Read More...

GPS Meets Einstein

Damian Pope, Senior Manager of Outreach Perimeter Institute for Theoretical Physics

Column Editor’s Note: The author of this article presented a fascinating talk about this topic at the 2010 OAPT Conference. Via the weblink provided in the article, readers can obtain access to a very useful student activity that demonstrates the importance of relativity in the operation of GPS.

The Global Positioning System (GPS) is one of the twentieth century’s greatest engineering marvels. Today, it’s the backbone of billions of dollars of economic activity. It’s used by a vast array of occupations including farmers, construction workers, doctors and even professional athletes. And all this comes on top of the more familiar personal applications like satellite navigation in cars and for hiking.

As well as being immensely practical, the GPS also involves some pretty cool physics — even, strangely enough, Einstein’s theory of relativity. Read More...

The Simple Demonstration of the Photoelectric Effect

Eknath V. Maratha, St. Catharines, Ontario

In 1900, Max Planck worked out a relatively simple energy radiation equation for a black body that described the distribution of radiation accurately over the entire range of frequencies. His equation was based on a crucial assumption: radiant energy is not infinitely subdivisible. Like matter, it exists in “particles.” These particles Planck called quanta, or in the singular, “quantum.” He further suggested that the size of the quantum, also known as “photon,” for any particular form of electromagnetic radiation, was in direct proportion to its frequency. In the visible spectrum, a photon of violet light would therefore contain more energy than a photon of red light. The small constant that is the ratio of the energy of a photon (E) and the frequency(v) of the photon radiation is called Planck’s constant and it is symbolized as h = E/v). It is now recognized as one of the fundamental constants of the universe. Planck’s theory, known as Quantum Theory, was applied by Einstein in explaining the photoelectric effect. Read More...

Lasers: A Solution looking for a Problem

Roberta Tevlin, OAPT Editor, Teacher Danforth CTI
Edited by Margaret Scora

Lasers are quantum light sources and they are everywhere. But what is quantum about them? The PhET simulation is a great tool to give students a feel for the quantum process called stimulated emission. Read More...

Particle Physics Crossword Solution

The solution to last week’s physics-themed crossword puzzle. How well did you do? Read More...

Particle Physics Crossword

The holidays are a time to relax with friends and family. In the spirit of holiday fun, the OAPT brings you a physics-themed crossword puzzle, filled with cryptic clues and bad puns. Read More...
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