Michelle Lee, Lisgar C. I.
michelle.lee@ocdsb.ca
Iain Braithwaite. John F. Ross C.V.I.
iainbraithwaite@ugdsb.on.ca
Milica Rakic, Essex DHS
mica@opusteno.com
Roberta Tevlin, Retired
roberta@tevlin.ca

Climate change may be the biggest problem that humanity has ever faced. The sooner that we deal with it, the more chance we have of succeeding. Physics teachers can play an important role in helping students understand the problem and its existing solutions, and help students feel empowered to take action. This article shows how you can teach about climate change, while reinforcing fundamental skills and concepts in the grade 11 physics curriculum. As usual, these OAPT resources are free. Read More...

Tags: Climate, Electricity, Energy, Forces, Kinematics

Milica Rakic, Essex DHS
mica@opusteno.com
Roberta Tevlin, retired
roberta@tevlin.ca

In order to prevent the worst of climate change, the emission of greenhouse gases (GHGs) has to be reduced as fast as possible. The enormity of this task can look overwhelming and can lead to climate despair. However, we already have the technology we need and a great source of information about this can be found on the website of Project Drawdown where they provide details of almost 100 solutions.

The goal of Project Drawdown is to show how we can ‘drawdown’ the emission of GHGs and then ‘drawdown’ the amount of these gases that are already in the air. This article shows how you can have your students examine 19 of these solutions which are involved in the production and use of electrical energy. This exercise is a good fit for the electricity unit in grade 9 science, the climate change unit in grade 10 science, the electricity unit in grade 11 university physics, and the energy transformation unit in grade 12 college physics. Read More...

Tags: Climate, Electricity, Energy, STEM

Richard Taylor, retired Physics teacher, Ottawa Carleton District School Board
Richard@teya.ca

“Brrrriiinngg! Hello, Richard? I was just cutting up some candles to use in the grade 10 optics labs and I got thinking about those cute little LED things you made. Do you think you could make some more for me?”

Certainly I remembered the grade 10 optics labs! Carefully prepping all those candles and optical benches, carefully priming the students to use the candles. Turn out the classroom lights and then the chaos begins. Matches breaking, fingers and hair getting singed, wax spilled on lab benches and floors (amazingly slippery!), images too dim to be seen, and which way up is that candle flame image anyway?

Several years ago, I came up with a better idea: mounting a red and a green LED on top of a 9 V battery. The LEDs produce about the same amount of light as a candle, and having the two different colours makes it easy to see whether an image is upright or inverted. After building 15 more of these, I thought it was about time to share the instructions so that other teachers can build their own. Read More...

Tags: Electricity, Optics

Chris Meyer, Past President, Ontario Association of Physics Teachers
chris_meyer1@sympatico.ca

At times electrons can seem awfully clever, as if they talk to one another and plan what each will do: “okay, so you two go along that path and I'll go along this one” or “I'll only give up ¼ of my energy here because the next load has a higher resistance and I need to give it ¾ of my energy”. How do they pull off these amazing feats of collaboration and foresight? For years I was genuinely stumped when trying to explain the rationale behind series and parallel phenomena; my attempts were all variations of “well, because that’s what happens”.

How do electrons “know” that there is another resistor connected in series down the road? How do they “know” which parallel path to choose? For that matter, how does a battery connected to a single resistor “know” how much current to push? There are so many mysteries of simple electric circuits! Let's explore the last question first, which will help us answer all the others. Read More...

Tags: Electricity, Field Theory

Chris Meyer
Past-President, OAPT
Chris_meyer1@sympatico.ca

Are you looking for exciting tasks for your students now that we have made the sudden switch to virtual teaching? You have come to the right place! A staple of our grade 12 physics classes is our physics challenges: cooperative-group problem-solving tasks that involve a physical apparatus, measurements, a prediction, and an experimental confirmation. One of my COVID projects has been making careful videos of these challenges that allow students to understand the problem and make measurements directly from the video. A separate solution video allows students to experimentally verify their predictions. Normally, I would write a long-winded, exhaustive article about the pedagogical design of the challenge process, but not this time! Instead, this will be a quick article so I can share these with you as quickly as possible! Looking for an engaging and rich task to wrap up your physics course with? Read on! Read More...

Tags: Assessment, Astronomy, Electricity, Energy, Momentum, Optics, Pedagogy, Remote Learning

Chris Meyer, Past President, Ontario Association of Physics Teachers
chris_meyer1@sympatico.ca

Why explore the idea of polarization?
A good way to learn about static electricity is by exploring things around us: run a comb through your hair, peel different fabrics apart, go down a plastic slide in a playground, there's so many possibilities! Another common one is the rubbed balloon sticking to a wall: an example of a charged and uncharged object interacting that requires some subtle science to explain. The grade 6 science curriculum mentions examples like this but leaves out the scientific tools to properly explain it. The grade 9 curriculum mentions charging by induction and again leaves out the science. Electrical interactions form the conceptual backbone for an understanding of atoms and molecules, electric circuits and fields, and why those annoying bits of Styrofoam keep sticking to our hands! The missing idea from the curriculum is polarization, a concept that explains the attraction between a charged and neutral object. Polarization also serves as a conceptual bridge between the topics of static and current electricity, which are often taught as two distinct topics. The curriculum provides a poor road map for learning about electricity; it will pay us great dividends as teachers to do a better job of this, so let's explore polarization! I want to share with you two lessons for grade 9 science that focus on this important electrical concept. Read More...

Tags: Electricity, Pedagogy

Joanne O’Meara, Professor, Department of Physics, University of Guelph
omeara@uoguelph.ca

When people think about what physicists do, they often jump directly to the esoteric, like quarks or globular clusters, and don’t necessarily see the myriad connections of physics to our everyday experiences. I’m not criticizing those among us devoted to the esoteric, but I do worry that we are missing out on inspiring and engaging with a large fraction of the science-curious by not taking the time to explore some of the fascinating physics on display in the natural world. As physicists, we are practiced at the art of asking ourselves Why? when we observe something beautiful, unusual, or unexpected, and the feeling that comes from figuring out the answer is what keeps us exploring. I love being able to bring these little explorations into my classroom, especially when I’m teaching first-year physics to biological science students, as helping them to see the relevance of what they are learning can have a profound effect on their motivation. From the beauty of a double rainbow, to penguins using bubbles to reduce drag, or the effect of polarization of scattered light on flies looking for someone/thing to bite, I love that look of wonder and appreciation on my students’ faces when we take a short tangent to extend our learning in optics or mechanics. Read More...

Tags: College, Electricity, Energy, Forces, Fluids, Light, Magnetism, Momentum, Projectile Motion, Safety

Chris Meyer, President, Ontario Association of Physics Teachers
chris_meyer1@sympatico.ca

When it comes to the study of electricity, it is the simplest ideas that students understand the worst. This is because electricity does its thing invisibly, so our job as teachers is to help make those microscopic goings-on visible. To do this, we create conceptual models that allow us to visualize what happens inside a circuit. I would like to share with you the resources I have created. Read More...

Tags: Electricity

Chris Meyer
President, Ontario Association of Physics Teachers
Hybrid Teacher-Coach for Science, Toronto District School Board
christopher.meyer@tdsb.on.ca

I have a question for you to think about, which I have chosen for two reasons: first, it is about electric circuits, which are fun; second, answering this question well requires thinking carefully about how we describe circuits. If you work through it carefully, you should discover one important reason why many students and teachers get tripped up when thinking about electric circuits. Now, I don’t want you getting bogged down in the weeds on this, so let’s start by assuming the devices are ohmic, meaning they faithfully obeys Ohm’s law. My question is this:

Which bulb would be brighter: a 10 Ω bulb or a 20 Ω bulb?

Take a few minutes to think about this question. What assumptions are you making about the circuit in which this bulb is found? Can you think of an example where either answer is the correct one? Keep thinking! And when you are ready for the full discussion, read on! Read More...

Tags: Electricity

Dave Doucette,OCT
Richmond Hill HS (retired)
STEAM Education Consultant, FAST Motion Studios, Toronto
doucettefamily@sympatico.ca

A 2016 paper¹ surveying Purdue University electrical engineering undergraduates discovered “…seniors were more confused than novices about physical concepts such as charge, current and electrical field.” The study did not reveal precise reasons but did caution that well-intentioned but incorrect analogies “usually transform into foggy concepts students carry towards graduation (p4).” This echoed a 2008 engineering-science paper² investigating obstacles to concept attainment of direct current. One barrier was weak modeling of the phenomenon, “…and identified the cause of this deficiency as lack of direct experience which can be remediated by creative instructional design.”

The actual mechanism of potential difference and direct current involves surface charge distribution. The challenge to develop this conceptual foundation is its invisible nature. Students cannot directly observe charge and ‘creative instructional design’ is needed to carefully scaffold inferences from static to moving charge. This paper suggests a series of activities to create the experiential background necessary for robust modelling of surface charge distribution. This conceptual foundation will be applied to series and parallel circuits to reinforce Kirchhoff’s laws. Read More...

Tags: Diversity, Electricity, Pedagogy

Tim McCarthy, Teacher, St. Ignatius of Loyola Catholic Secondary School
mccarthyt@hcdsb.org

Controlled experiments with three factors are a great way for physics students to practice identifying and testing factors that may affect a situation. They provide an excellent opportunity to practice the Scientific Investigation Skills found in Strand A. The students are provided with a situation, brainstorm possible factors that may affect the situation, reduce the list of factors to three that can be tested in the physics lab, develop hypotheses, design procedures to test the factors, test the factors, analyze the data, perform experimental error analysis, and draw conclusions on the effects the three factors have had on the original situation.

My struggle has been to find situations that easily fit this format and that also match the curriculum specific expectations. I have created one three-factor controlled experiment for each of the six units in my 12C physics course. The three-factor experiment in the first unit is used as assessment for learning (formative) to teach the students how to do a controlled experiment. The remaining five experiments are used as assessment of learning (summative). Simulations are used for some experiments as I do not have the necessary equipment to perform all them in the lab. Read More...

Tags: Assessment, College, Electricity, Fluids, Forces, Kinematics, Magnetism, Pedagogy, Pressure

Tim McCarthy, Teacher, St. Ignatius of Loyola Catholic Secondary School, Oakville, ON
mccarthyt@hcdsb.org

Coding is an important skill for physics students to learn. Grade 12 College and Grade 11 University physics students must build series and parallel circuits, so why not use coding to control them and model an everyday, real-world situation? This can be done by first using TinkerCAD simulations, followed by construction of the simulation using real components; Arduino UNO R3 microcontroller boards, breadboards, LEDs, resistors and wires. Students have a high level of satisfaction as they complete a task that is brand new to most and learn skills that they are likely to need in their post-secondary education. Read More...

Tags: College, Electricity, Technology

Andrew Moffat, Teacher Bishop Strachan School
amoffat@bss.on.ca

Students often struggle with the “Physics” unit in grade 9 Science — electricity. This can lead to a negative association with Physics and fewer students taking grade 11 and 12 Physics. At our school we have tried to make the electricity unit (and specifically the idea of circuits) more fun and engaging by having students create an electric greeting card consisting of LEDs and a battery. This can be done for around $2 per student. Read More...

Tags: Electricity, Light

Chris Meyer, President OAPT
christopher.meyer@tdsb.on.ca

Electricity is almost always invisible; we never get to see electrons doing their thing. Only occasionally do we observe some by-product of electrical shenanigans like a spark, a glow, or a warm battery. This makes learning about electricity tough. As a result, many students (and even some teachers!) don’t develop a clear mental model representing how electrons move in a circuit. There are two important ideas are often missing from our mental models. Read More...

Tags: Electricity

Chris Meyer, President, Ontario Association of Physics Teachers
Christopher.meyer@tdsb.on.ca

Static electricity might very well be the most important topic taught in high school science. Exploring static electricity teaches us how charged particles behave, which becomes the basis for understanding the structure of the atom, chemical reactions, the behaviour of complex biological molecules, cells, and even human thought. Static electricity is challenging to understand because it is invisible; we can’t see the particles doing their thing. As a result, we need to help students construct concrete, visual models of charged particles and provide students with visual ways of verifying their understanding of static electricity. Read More...

Tags: Electricity

Chris Meyer
President, Ontario Association of Physics Teachers

Time to Let Go
It’s time! Conventional current, the mysterious flow of positively charged particles in current electricity, has outlived its usefulness. This model hinders the development of clear physical understanding and places an additional, unnecessary conceptual burden on all our students. We ought to let the few students who pursue the electrical trades, electrical engineering, or physics deal with this awkward relic. Use electron current in high school. It’s time to let go of the ghosts from our disciplinary past and focus on improving our students’ learning. Read More...

Tags: Electricity, Pedagogy

Roberta Tevlin
Teacher at Danforth CTI, Manager OAPT Newsletter

The concept of fields is fundamental to our modern understanding of physics and the Ontario curriculum dedicates one of the five units in 12U physics to Gravitational, Electric and Magnetic Fields. I have struggled for many years to find ways to make this important but abstract concept more tangible to my students. Here is what I have come up with so far. Read More...

Tags: Electricity, Field Theory, Magnetism, Modern Physics

David Gervais
STAO Safety Chair

The traditional incandescent bulbs used for teaching series and parallel circuits are rated for 3 V or 6 V. The problem is that many power supplies can generate 12 to 15 V. As a result, it is common to have many blown bulbs. With several sections teaching this unit, bulbs can quickly become in short supply. Each bulb replacement can cost $1.00 each, and often are included in the general department order at the end of each semester. For those teachers using breadboards, traditional bulbs are also not easily adapted to fit into the small holes. LEDs are a great alternative for many reasons. Read More...

Tags: Electricity, Light

Matthew Craig, Teacher at the Community Hebrew Academy of Toronto
matt.simon.craig@gmail.com

I’ve been programming a suite of PC/MAC/Android simulations designed for teaching the Ontario curriculum for science and physics. One topic for which I have never had an effective simulation is the metal-leaf electroscope for grade 9 science, and revisited briefly in grade 12 physics.

The electroscope simulation I have developed is a very simple simulation that can be used to show induced charge separation, charging by contact, charging by induction and grounding. Read More...

Tags: Electricity, Technology

Roberta Tevlin, Teacher at Danforth CTI
roberta.tevlin@tdsb.on.ca

One of the biggest problems facing the world right now is how to generate the electricity that we want without destroying the environment. This is a very complicated problem and we are supposed to help our students understand this issue in all four grades in high school: grade 9 Science (Electricity), grade 10 Science (Climate Change), grade 11 Physics (Energy and Society) and grade 12C Physics (Energy Transformations). This summer I found a great tool to help with this. Read More...

Tags: Electricity, Energy

Bonnie Lasby Physical and Engineering Science Dean’s Office University of Guelph
blasby@uoguelph.ca

I prefer to do this as an activity as opposed to a demonstration, and have found that it works very well for students in Grades 7 to 12 visiting the University. I start with a discussion about sound and then compare a speaker to the human ear. In the discussion on speakers, I also talk about magnets and how they work, and I explain the difference between permanent magnets and electromagnets. After this discussion, I explain how to make speakers using a plastic cup, a magnet, and a coil of wire. Each student makes his/her own speaker and then tests it. Read More...

Tags: Electricity, STEM, Waves and Sound

Joanne O’Meara, Department of Physics, University of Guelph
omeara@physics.uoguelph.ca

This demonstration is a nice way to illustrate the P = I ²R relationship that is discussed in electric circuits. Figure 1 illustrates the equipment: a Variac transformer takes the wall output of 120 V and generates a variable voltage from 0 to 140 V. This is then sent through a Hammond Manufacturing transformer (167X5), converting down to 5 V output. We use this second transformer in order to increase the current through the wires. The output from the second transformer is connected to three wires in series: approximately 10 cm in length of each of ~18 gauge Nichrome, steel and copper. A piece of folded paper is placed on each wire. Read More...

Tags: Electricity, Safety

Leigh Palmer, Simon Fraser University

Here's a demonstration that will make your students think more carefully about the meanings of the terms voltage, electromotive force, and potential difference. A transformer is necessary for the demonstration. Read More...

Tags: Electricity, Magnetism

John Pitre, University of Toronto

In the December 2004 issue of The Physics Teacher, Christopher Chiaverina described a motor consisting of four components: a battery, a cylindrical rare earth magnet, a small piece of copper wire, and a steel nail. Since I know that many of our members do not have ready access to this journal, I have essentially reproduced his article here. Read More...

Tags: Electricity, Magnetism

Peter Scovil, Waterford, ON
petescov@enoreo.on.ca

I like music, and enjoy playing the guitar, so the following demo caught my eye (or ear?). It was in the Jan. '95 issue of The Physics Teacher (p.58) by G.R. Davies of South Africa. It is a good example of electromagnetic induction that is easy for students to understand. Read More...

Tags: Electricity, Magnetism, Waves and Sound

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

This simple little homemade device can provide a very effective demonstration of AC current, it’s fun, and it’s cheap! All you need is a little neon lamp, a resistor and an AC cord. Solder one leg of the neon lamp in series with a 10K, 1/2 watt resistor, and then attach to the AC cord. Heat shrink tubing is excellent insulation for this construction, otherwise use carefully applied electrical tape. Be sure to insulate throughly, you have AC power here. Read More...

Tags: Electricity

John M. Pitre, Department of Physics, University of Toronto
pitre@faraday.physics.utoronto.ca

In the January 1997 issue of The Physics Teacher, two articles appeared detailing the use of rare earth magnets to demonstrate Lenz’s Law in the classroom. The principle involved is that a permanent magnet falling through a tubular conductor will induce a current in the conductor and hence a magnetic field which will oppose the magnetic field of the permanent magnet and thus slow its rate of fall. This article gives variations of the methods discussed in those papers. Read More...

Tags: Electricity, Magnetism

Roland Meisel, Ridgeway Crystal Beach High School
rollym@iaw.on.ca

A Tesla coil circuit generally consists of some sort of step-up transformer along with a tuned oscillator. The B-10 coil sold by Cenco Scientific is a compact device which produces 40-50 kV at frequencies of 3-4 MHz. The schematic diagram shows an inductance connected to an AC circuit. As the AC goes through its cycle, the inductance builds up a high reverse potential (similar to the arcing at the commutator of an electric motor) which can exceed the breakdown resistance of the spark gap in the oscillator circuit. When this happens, the resistance across the gap drops effectively to zero, and causes the tuned circuit to “ring” electrically, much like hitting a tuning fork. A high-voltage high-frequency AC potential is induced at the tip. This is the “simple” explanation which high school students can usually follow. For those who wish to see the differential equations describing what is going on, may I suggest an advanced book on electrical physics! Read More...

Tags: Electricity

John Childs, Grenville Christian College, Brockville

Two demonstrations from John Childs. Read More...

Tags: Electricity, Magnetism, Waves and Sound

Roland Meisel, Ridgeway Crystal Beach High School
rolameis@village.ca

A current can be run through a hotdog in order to cook it. There are commercial hotdog cookers that make use of this principle. I use it near the end of the unit on resistance in the Grade 12 Physics course. Read More...

Tags: Electricity

Peter Zuech, Mother Teresa S.S., Scarborough

This idea was born while watching the Tonight Show. A popular entertainer demonstrated a wooden board upon which four coloured light bulbs in sockets were mounted along with a corresponding set of four coloured switches. No matter how the bulbs were rearranged in the sockets, the blue switch turned the blue bulb on and off, the red switch operated the red bulb, and so on. Johnny examined the bulbs, found them to be “normal” and was convinced that it was magic. Unable to determine how the four-bulb unit operated, we designed a simpler two-bulb version for use as a discrepant event in current electricity. Our unit used two white bulbs but coloured ones could be used as in the original unit. The only skills required to construct the unit are an ability to solder and the willingness to tinker a little. Read More...

Tags: Electricity

Frank Allan, Science Co-ordinator, Ottawa Board of Education

The world’s simplest speaker can be constructed in a matter of seconds. Read More...

Tags: Electricity, Magnetism

Robert Ehrlich, Physics Department, George Mason University

The world's simplest motor can be constructed in less than five minutes. Read More...

Tags: Electricity, Magnetism

Peter Scovil, Waterford District High School

Have you had difficulties explaining to students the complexities of the D.C. motor? Read More...

Tags: Electricity, Magnetism

Gyula Lorincz, University of Toronto

Many of our old favourite electrostatics demonstrations can be improved using ping pong balls painted with graphite to replace pith balls. In particular, a simple but very sensitive electrostatic torsion balance can be used to demonstrate both the attraction of opposite charges and the repulsion of like charges. Read More...

Tags: Electricity

Roland Meisel, Ridgeway-Crystal Beach High School

An electrostatic precipitator can be assembled in less than half an hour using parts commonly found around the science department in a high school. I have used it as a demonstration in classes ranging from grade 10 general science to grade 13 physics. In addition, it has spawned several senior science projects using it as an investigative tool. Read More...

Tags: Electricity