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Spring Surprise: Projectile Motion made Fun, Mathematical and Real!

Roberta Tevlin, Editor, OAPT Newsletter
Roberta.tevlin@tdsb.on.ca
Edited by Tim Langford

Projectile motion often involves a lot of mathematical problem-solving that is overly simplified and highly contrived. Football players do not stop to calculate the range before making a pass. Invading armies might want to make calculations for siege weapons, but these tend to be too complicated (trebuchets) or involve too much energy loss (catapults). Guess and check, was probably the preferred technique. Fortunately there is a cheap and reliable projectile launcher that you can use to show that physics works. Your students will be able to use it to hit a target on their first shot by using calculations for conservation of energy and projectile motion. Read More...

The Physics of Stunt Action Field Trip

Sarah Grimes, Justin Findlay, Dave Doucette, Physics Teachers

Movies, television and video games are awash with heroes, villains and their super-sized cousins. As media consumers, we are captivated by seemingly impossible feats of physical prowess. In fact, they are more than seemingly impossible — they are literally impossible. The magic of cinema coerces us to suspend disbelief and accept the impossible as plausible. How is this done?

With CGI, pulleys, wire-rigging and physics! The magic seen in Mutant X, Lost Girl and other programs was combined at FAST (Fight Action Stunt Team) Motion Studios in Toronto, a highly experienced international team of stunt action coordinators, artists and riggers. Students can visit the studio and experience the process first-hand. While there, they will make connections to the physics they’ve learned and will be exposed to career opportunities in a recession-proof industry. Read More...

A Simple Vector Development of Centripetal Acceleration

Dave Doucette, OAPT Vice-President
doucettefamily@sympatico.ca

While teaching uniform circular motion in high school, I struggled with developing the ac = v2/r relationship in an intuitive and cognitively meaningful way. Geometric arguments do not resonate with students. They accept on faith but often with little interest or insight. Here is an approach that may do a better job. Read More...

Rockets: A Beginners Guide Part 3

John Berrigan, Teacher Oakville Trafalger H.S.
berriganj@hdsb.ca

In the previous article we found the main factors that determine the thrust of a rocket engine. We rearranged the formula and determined the Impulse of the formula for rockets.EQN1 With Elon Musk discussing his Mars rocket last week, http://www.spacex.com/mars, now is a good time to discuss how Impulse can be used to eventually determine the efficiency of a rocket engine. Read More...

GIFs in the Classroom

Eric Haller, OCT
rickyhaller@hotmail.com

It’s autumn, and maybe you’re looking for a new way to impress your physics students this semester. I find it easy to amaze my class by using various forms of technology in my lessons. Often our students don’t realize how tech savvy physicists need to be, picturing us using chalkboards to give lectures and not using supercomputers at CERN or developing video games which use physics simulations. Ok maybe I’ve never been to CERN or made a video game, but I can make my own GIFs. In this article I’m going to show you some GIFs you can use in your lessons, and also teach you how to make your own GIFs. Read More...

Rockets: A Beginners Guide Part 2

John Berrigan, Teacher Oakville Trafalger H.S.
berriganj@hdsb.ca

In the previous article we learnt how to find the largest possible delta-V that a rocket can experience. In this article, we are going to find the thrust of a rocket by using the fundamentals of conservation of momentum. This will be similar to what we did in the last article, however this time we will use variables instead specific masses and velocities. Furthermore, the cart is now a rocket, as this is rocket science! Read More...

A Browser-Based No-Fuss Gravitation Simulator

Michel Enns, Teacher Runnymede CI
Michel.enns@tdsb.on.ca

I have been frustrated with gravitation simulators over the years because they stop working when the computers are updated. To avoid this, I have made one that is browser-based and will run on any device. You can find it at www3.sympatico.ca/michael.enns. One non-standard thing that it can do is simulate the formation of a solar system with a thousand random masses. Read More...

Rockets: A Beginners Guide Part 1

John Berrigan, Teacher Oakville Trafalger H.S.
berriganj@hdsb.ca

Interest in rockets is skyrocketing due to the recent successes of SpaceX and Blue Origin, two private companies developing spaceflight. This is an ideal time to introduce students to the physics behind rockets which are an exciting illustration of the conservation of momentum and relative motion.   Read More...

Physics On Ice: A Field Trip on Force and Motion

Margaret Scora, Teacher at M. Paul Dwyer CHS, Oshawa ON
Margaret.scora@dcdsb.ca

Taking a class to Wonderland™ to investigate force and motion can be an expensive and frustrating adventure. The local ice rink is probably only 15 minutes away for most of us, a lot cheaper, and you can be there and back in less than three hours with a whole lot of new experiences for your students to ponder and discuss. Read More...

Four Cheers for the Holistic Demo

Gavin Kanowitz, Teacher at AY Jackson SS
gavin.kanowitz@tdsb.on.ca

The ‘Demo’ is one of the most powerful tools that physics teachers have. It can hook the students’ interest right away. If you frame the demo with a pre and post dialogue, it can also ignite their learning.

There is no hard and fast rule as to when an educator should perform a demo. I prefer using them as an intro to the topic. Other teachers choose to defer to demos as a means of solidifying a key idea at a later stage of concept development. There is certainly no shortage of demos — a quick glance at the OAPT website will alert you to that, but what is often missing in demo descriptions is the pedagogy that surrounds the show. Read More...

Rotational Motion and the Chain Saw

John Caranci
physix1@look.ca

This demonstration is used to introduce rotational motion by using the complex motion of a chain-saw chain. You probably have seen many demonstrations over the years but this is one that can be done with the simplest equipment: one elastic band and a sheet of newsprint. Read More...

Motion of the Centre of Mass 2

Patrick Whippey, Department of Physics & Astronomy, The University of Western Ontario

Do we really believe Newton’s Laws? This demonstration was born many years ago when a perceptive student challenged the assertion that a body free to move always rotates about its centre of mass. This demonstration requires an air table. Read More...

Motion of the Centre of Mass 1

Patrick Whippey, Department of Physics & Astronomy, The University of Western Ontario

Do we really believe Newton’s Laws? This demonstration was born many years ago when a perceptive student challenged the assertion that a body free to move always rotates about its centre of mass. This demonstration requires an air table. Read More...

How to Make a Lighted Throwing Stick to Show that the Centre of Mass is a “Special Place”

Forest Fyfe, Department of Physics and Atmospheric Physics Dalhousie University

This article is reprinted from Physics in Canada, Volume 65, No. 3, pg.141 (2009), with permission of the Canadian Association of Physicists (CAP).

Illustrating the concepts of centre of mass and centre-of-mass motion to an introductory physics class can be a challenge to a physics instructor. The topic can be very mathematically complex and is not necessarily intuitively obvious. A device that demonstrates how the centre of mass of an object moves as compared to the motion of a point on the object away from the centre of mass would provide an excellent qualitative illustration of this. At Dalhousie University we have constructed just such a device, our lighted throwing sticks. Read More...

Balancing on the Edge and Inexpensive Accelerometers

Diana Hall, Bell High School, Nepean
Diana_Hall@ocdsb.edu.on.ca

Diana Hall presents two simple demonstrations. Read More...

Two-Minute Impromptu Demos

Ed van den Berg and Rosea van den Berg, University of San Carlos, Talamban Campus, Cebu City, Philippines
edberg@durian.usc.edu.ph

This article was excerpted (with the authors’s permission) from a longer article in The Physics Teacher (Sept. 1998, p.356-8).

What can we do to have clear and exciting lessons without a great amount of demonstration apparatus and hours of preparation each day? We present here a collection of small and quick demos that require no equipment beyond what is present in a classroom (chalk, chairs, students, books, paper, backpacks and their contents). Some are to prove something, but most are to illustrate, visualize, or simulate. These basic and well-tried ideas will stimulate students and revive the instructor who has spent a late night checking student papers. Have fun! Read More...

Ball and Ramp Races

John Childs, Grenville Christian College, Brockville
jchilds@grenvillecc.ca

This is a good exercise to use after you’ve done kinematics, dynamics, and energy. We all talk about the kinetic and potential energy of roller coasters and their speeds, and the demonstration will let your students apply their critical thinking skills to this kind of situation. Be sure to have your students examine the setup and predict the outcome, before you run the demo. The question is: “Which ball gets to the end of the ramp first?” Read More...

Dumb Tricks with Metre Sticks

John Wylie, Toronto French School
jwylie@tfs.on.ca

Here are two tricks, sorry, demonstrations that you can store away for when you have a few minutes to kill and all you have available is a metre stick, or when you just feel the need to show off in front of impressionable young students. They both are opportunities to prove that a knowledge of physics is better than being young and co-ordinated. Read More...

Gold Wedding Ring — Monkey and the Pulley

Murray D. Kucherawy, A.B. Lucas S.S., London

Effective classroom demonstrations often require tinkering with temperamental equipment. With the permission of the editor, I would like to share a “thought demonstration” that requires no equipment, but which still makes a surprising point. Read More...

Flipping for Physics

John Wylie, The Toronto French School

Here is a good demonstration that can be used in its simplest form to show stable and unstable equilibria or, in a more advanced version, to illustrate some finer points about moments of inertia and angular motion. The material needed could not be simpler. You need a board. There are no special requirements here except that the board be rectangular and have three distinctly different dimensions. In a pinch, I have used a good-sized physics text book held closed by a strong elastic. Most brief cases work and if students feel lucky, they can try out their calculators. Read More...

Huge Pendulum, Centre of Mass, and Magnetic Force

John Earnshaw, Trent University

The author presents three demonstrations: a large pendulum, the centre of mass of a person, and the magnetic force on a beam of electrons. Read More...

Standing Waves — The Can that Comes Back

Pauline Plooard, Fenelon Falls Secondary School

Two quick demonstrations from Pauline Plooard. Read More...

Sand and Soup

Patrick Whippey, Department of Physics, University of Western Ontario

Two intriguing demonstrations from Patrick Whippey. Read More...

Falling Faster Than ‘g’

T. Dean Gaily, University of Western Ontario

A simple lecture demonstration to illustrate that some objects do ‘fall’ with an acceleration greater than 9.8 m/s2 is constructed from two pieces of 2.5 cm × 15 cm lumber approximately 1 m in length (1” × 6” × 39”), hinged together at one end. A small marble placed in a notch at or near the end of the “falling” board can be made to fall slower than the board and land in the cup strategically placed on the falling board. Read More...
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