The Engineer`s Pulse

A Happy Teacher

2025-07-28T14:54:00.000-04:00

Something happens to me as August looms. Summer brain gets a message from somewhere telling it that its time lying horizontally binging The Bear will soon come to an end. It will be replaced with time in a classroom with students who want to learn physics (feel free to substitute 'want to' with 'need to', or even 'have to', it really varies).

I came across a wonderful quote from a famous physicist today. It made me stop and look forward to the academic year ahead:

"Students don't need a perfect teacher. They need a happy teacher who's going to make them excited to come to school and grow a love for learning." - Richard Feynman

As someone whose teaching style has been described as 'jolly', this quote is reassuring. There are days where a class goes exactly to plan and others that fall flat, but if the teacher can exude positivity, then there is a chance the students will follow suit, creating conditions for a great experience.

Feynman was one of the leading physicists of the twentieth century, making major contributions to our understanding of quantum physics. He seems to have been a mixed bag of intelligence and quirkiness. His most famous book, Surely your Joking, Mr Feynman! reveals all sides of his character, from the very bright to the very eccentric. But back to his statement about teaching...

Teaching is one of many professions where a positive attitude gets you much of the way there. You still need to sweat the details, but there should be no sense of dread should the class feel distracted on a Thursday afternoon lecture. My teacher's guidebook goes as follows:

Have empathy
Build trust
Establish connection
Be supportive
Provide ample feedback
Encourage participation
Promote curiosity

Every teacher has access to content they can disseminate to their students. Every teacher should hone their pedagogical approach. But a class can only work so well if a wall exists between teacher and student. I think any teacher who does the things in the checklist above can get their class where they need to get.

I was once at a teacher's conference, where the audience was asked to think of their favourite teachers, and what made them stand out. It was rarely their brilliance or their pedagogy - it was their humanity. In keeping with that spirit, I will adopt the mantra, "Positivity over perfection," this semester. Now, to finish The Bear.

How worried to be about asteroid 2024 YR4

2025-02-19T14:13:00.003-05:00

A student visited my office today asking about an asteroid she heard about in the news. As though we needed something else to worry about, right? NASA now predicts a roughly 3% likelihood that asteroid 2024 YR4 will hit our planet. On Dec 22, 2032, YR4, a football-field sized asteroid travelling around 17 km/s, will reach us and hopefully miss.

Students are usually surprised that we can predict the arrival of this body with so much precision (the exact date) so long in advance. What makes it relatively easy to do is that the asteroid is on an elliptical path around the Sun. All other bodies have little to no influence on it. Knowledge of the asteroid's position, speed, and direction at any moment enables us to predict its future trajectory around the Sun with great accuracy. The 'when' of it is extremely precise, but the 'where' of it has some uncertainty, hence the 3% chance. For now, we can draw an area of a certain size in space that YR4 will shoot through on Dec 22, 2032, and Earth will fill a small portion of that space at that time.

The amount of energy carried by an asteroid is the key metric for assessing the level of damage its collision with Earth would cause. The energy is usually expressed as 'equivalent to X megatons of TNT explosives', which does nothing to calm fears that the public may have. The good news regarding 2024 YR4 is that it would collide with an energy equivalent to about '10 Megatons of TNT' (that is 10,000,000 tons, but still about 100,000 times less than the one that marked the end of the Jurassic).

Though this is not an extinction sort of asteroid, the press has called it a city killer, because it needs to sound at least a little scary. But the term is also appropriate, because the footprint of destruction were this asteroid to strike Earth would be in the area of 2,000 square kilometers, which is bigger than most cities. I mean, even 1 ton of TNT is not something I'd want to set off in my backyard, so 10,000,000 of them sounds like it very well could level a city.

So, what do we do? For now, we wait, and keep monitoring it. With more precise data, the likelihood could eventually reduce to 0%. The trouble is, in the unlikely event that the odds increase dramatically, a plan will need to be made and launched in a hurry.

Will the plan involve Bruce Willis and nuclear bombs being detonated from inside the asteroid? Sadly, no. Not only is this a way more impractical option for many reasons (like, nukes in space, what could go wrong?), we also could not be completely sure of its outcome. A more elegant approach would be to launch a large rocket right into YR4, to change its course at just the right moment (small changes of direction lead to large deviations later in a trajectory). This approach has been successfully tested before: NASA's DART mission successfully deflected an asteroid larger than this one in 2022.

The tricky part is determining when or if to 'pull the trigger'. DART cost over 300M USD, so it is not something to undertake just for fun (though it does sound extremely fun!).

How much should we worry? Not much, for now, but we will take a very careful look at YR4 when it passes our neighborhood of the solar system next in 2028, and reassess. Still, it is nice to know that we have a plan that has worked in the past if YR4's trajectory gets too close for comfort.

Viral Fake Physics Videos

2025-01-13T19:40:00.001-05:00

I have spent most of my career with an eye towards fighting science misinformation. This has been a losing battle, of course, but one I feel a duty to see through. Typically, I take aim at outlandish claims made by people with hidden agendas, from classics like "Burning fossil fuels does not contribute to climate change" to "Just wear this bracelet and your ailments will disappear." Those hits keep on coming, but there is a new kid on the block that really has me scratching my head.

As 2025 begins, there has been a sudden uptick in the number of fake physics videos appearing in my social media feeds. Fake physics videos are not to be confused with deep fakes, which involve AI. In these fake physics videos, we have random people setting up what look to be legitimate physics demonstrations. They lay out spoons and batteries and suddenly a coin appears to levitate. In the next, they show a collision between marbles that appears to defy Newton's laws. After some digging, I discovered that the former uses a camera trick and the latter hides a magnet in some of the spheres.

I am a bit dumbfounded over this... I despise the traditional McScientists who seek to disinform people, but at least I understand that foe. They have a purpose, misguided though it may be. Like, the way a wasp buzzing around your head is just an unfortunate manifestation of nature, so too are McScientists. But what to make of this new thing?

There are so many excellent physics videos out there. The best of them show an experimental setup, allow the audience to formulate a prediction on what will happen, then run the demonstration, and finish off with a clear explanation of the physics principles at work. Veritasium and The Slow Mo Guys are two of my favourite YouTube channels containing countless videos of this sort. The take home message is that physics is fascinating. Nature, without trickery, is mind-blowing on its own. What purpose does misleading people about science serve? Like, "I have them questioning Newton's Laws!" or "Now they'll learn physics wrong, hah!"

When you stop and think of it, magic shows are similar to this. Whether it is sleight of hand or another illusion, magic always seeks to leave audiences surprised by what they are seeing. But there is an important difference: in a magic show, the whole premise is "I am going to try to fool you, see if you can spot how." The audience is, effectively, in on it. And besides being (sometimes) entertaining, magic shows test the audience's critical thinking. Fake physics videos are posing as the real deal. If they began by stating, "The demo you are about to see has been faked in some way, see if you can figure out how," I could get on board with that.

I'm proud that I was able to spot that these videos were disingenuous. If I'm being honest, I kind of enjoyed debunking them. I'm even tempted to show them to my students.

But I still don't understand the motivation for making the videos. Is it just for attention? It is, isn't it? Geez. The twenty-first century is no time for an idealist like me.

Escaping a Crazy Semester

2024-12-06T13:48:00.007-05:00

It has been a long semester for so many reasons. There were so many distractions outside of the classroom - too many to list. Civil unrest around the world, marches in the streets, a provincial government cutting budgets and enforcing exhausting laws. On top of that, my lab was situated in a loud construction zone, so I could not hear myself think, let alone communicate with my students... I sometimes must remind myself that we reside on a celestial spec sailing through the cosmos; it helps me remember to keep life's small nuisances small.

What I know for sure is that time spent with my class in my classroom is my refuge and an escape from the worries of the world. I decided to celebrate the end of my mechanics course this morning by setting up and running a 'Physics Escape RoomTM'.

This semester's escape room was Christmas-themed

For those less nerdy than me and unfamiliar with Escape Rooms, they are enclosed spaces where participants need to decode many puzzles to eventually escape in an allotted amount of time. My wife and I have spent countless hours in these rooms; our intensity and determination to succeed often scares the friends who join us.

My escape room is a bit different than the regular kind, in that there are fewer logic puzzles, and more physics scenarios with unknowns that can only be solved by applying physical laws. It is a fair bit of work to set these rooms up, but it serves as a great review of what my class learned in Mechanics class this semester, and ends it off on a fun note. Many students expend so much energy feeling anxious about performing well in college, that they forget to ever have fun. I would argue that if you can learn while having fun, you will remember those things for longer.

My students feel trepidation over the final exams that are around the corner. On top of teaching physics, I often feel like a councilor or life coach, urging them to take care of themselves, take deep breaths, and not to overstress. Just like an escape room, to succeed in final exams, you need to strike a balance. Success is arrived at by students who are a bit stressed (enough to be continuously engaged) but not so stressed that they cannot focus on the task at hand.

I got the idea to create escape rooms for physics years ago. I always enjoyed escape room challenges that went beyond code breaking. I liked when prior knowledge of things, like chess for instance, could be called upon. Like, your knowledge becomes this superpower that is valued by your group. I want my students to feel that way about physics. Throughout the semester, they have developed new ways to see the world, and they should feel empowered by their new knowledge and ability to analyze nature.

Lab Layout in Mechanics Escape Room

When I was in college, I had a biology class where many stations were set up, and you could spend 15 minutes, say, observing a station and drawing conclusions, like a bunch of mini labs. This was way more interesting to me than one long lab where you measure this, then that, then change this and re-measure, etc. Those labs are necessary, but they can get boring after a while. As seen above, demo stations form the basis of a Physics Escape RoomTM.

Another difference between traditional escape rooms, which have one team at a time, is that my room has many teams competing to get out first. This year, three teams managed to escape the room in the 1 hr 15 min time allotment. To their dissappointment, no bonus points are awarded for getting out first. Still, the top team in each section happily posed for a pic afterwards to be featured in The Engineer's Pulse.

Group 1 victors (left to right): Xavier, Amélia, and Luc

[notice the hole in the ceiling at the top of this photo - with all the work going on in and outside of our lab this semester, I am just pleased that no student fell through the floor]

Group 2 victors (left to right): Nicholas, David, Avoy, and Trong-Don (missing from photo: Malik)

Dear my beloved Fall 2024 mechanics students, whether or not you physically escaped the room today, you have completed the semester, and I hope you found it to be an enriching experience. Now it is time to lock yourself in a different room and study ;)

Good luck on your finals!

'Orbital' has left me breathless and musing about weightlessness

2024-07-22T16:35:00.004-04:00

The summer is half over, but the winner for my top read has already been determined. Orbital: A Novel, by Samantha Harvey, has enraptured me. It is a story about one day in the lives of a crew of six astronauts in low Earth orbit. We orbit with them, experience sixteen sunrises and sunsets, perform weightless tasks, but mostly, follow their inner monologues, which I would describe as meditations on nature and space.

The novel is a love letter to Earth and a prayer that we will learn to inhabit it with grace. Harvey describes the daytime view of Earth as "... the humanless simplicity of land and sea. The way the planet seems to breathe, an animal unto itself. It's the planet's indifferent turning in indifferent space and the perfection of the sphere which transcends all language."

Summer is a wonderful time to read this book. One thing I've always enjoyed about physics is how it opens up amazing conversations during late evening strolls, when the stars come out. At such times, with the Sun blocked out, we see the vastness beyond our atmosphere, and feel so very small. This sense of awe overcomes us. Orbital gives us this same feeling, but from a privileged vantage point some 400 km above our planet.

Many students have asked me if I would like to travel to space, and I tell them there's no point thinking about it because my wife wouldn't let me. The truth is that while I would love to see Earth with my own eyes from low Earth orbit, I do not think my body would enjoy the experience of weightlessness. Most amusement park rides are no-go zones for me now, which totally sucks, because they were a delight before I turned thirty.

It is not possible to experience weightlessness for a significant amount of time in our day-to-day lives, because along with Earth's gravitational force, we are always subjected to some other contact force (like the push of a chair onto our butt, say). An orbit is a perpetual state of falling; astronauts are falling along with the capsule they inhabit. The reason satellites don't fall down to Earth's surface is because they have a sufficient lateral speed (many km/s). A circular orbit maintains its constant speed because there is no atmosphere to slow it down, so round and round it goes.

Okay, quick tangent... Here's a fun little question that just came to me: Standing on the surface of the Moon, with its negligible atmosphere, how hard would I need to throw a rock for it to complete a full orbit and hit me in the back of my head? A quick application of Newton's second law leads to the result: v = sqrt(GM/R), where M and R are the Moon's mass and radius, respectively (G is the universal gravitational constant). Plugging values in, we get a speed of 1,680 m/s (over 6,000 km/h). I can't throw that fast, and in any case, would prefer not to get hit in the back of my head by a rock moving that fast.

Let's get back to the feeling of weightlessness. When you jump off of a diving board, you feel weightless from the moment your feet leave the board up until your body enters the water; a few brief seconds of weightlessness. I cannot fathom enduring that 'organs floating in the ether of my rib-cage' feeling for days, weeks, and even months, without a break, as astronauts do.

There really is no way to simulate weightlessness on Earth. Even skydiving does not replicate the sensation, because we quickly reach terminal velocity, where the upward drag force matches the downward weight force. Yes, we are falling, but we feel our weight. As far as your innards are concerned, it's like lying flat on your bed, only it is the air giving the steady upward push.

A compromise between the brevity of diving into a pool and, say, a 90-minute complete circling of Earth in a spacecraft, is a zero-g airplane, which cuts off its engine for about 22 seconds, during which its thrill-seeking passengers float around the cabin. It then repeats the parabolic maneuver many more times until someone pukes.

I guess I will have to be satisfied with musing about space. For this earthbound physics teacher, reading Orbital will have to suffice.

Wishing you a summer of blue skies and starry nights.

Totally Stoked for Totality!

2024-04-06T13:43:00.001-04:00

For readers far away from the path of totality for the upcoming solar eclipse, my apologies, but as a Montrealer, I will be getting one minute in the full shade of the sun on Monday, April 8. It is truly a once-in-a-lifetime experience, and I am excited to the point of losing sleep. It inspired me to write this extended piece in the Montreal Gazette: Totally Stoked About Totality.

Totality will occur at 3:27 p.m. for Montrealers. But as we are on the northern edge, it will be shorter than those along the middle of the path by a couple of minutes. Still, one moment would be sufficient to sear the event in my memory.

I was inspired to write the piece by a colleague of mine and my feeling that the average person is not as psyched as they ought to be. The one message I want to convey to anyone that has an easy opportunity to enter totality is this: DO IT! The worst case scenario is that this few minute commitment does not rock your world, but in all likelihood, it will be unforgettable, and more so if you experience it with loved ones.

*** Remember to protect your eyes. Wear eclipse viewing glasses whenever looking directly at the sun, with one exception: the brief minute of totality. You must remove them during the big moment or you'll miss it.

My Fall Mechanics Class - thanks for the escape!

2023-12-06T12:56:00.000-05:00

Oftentimes, as the end of year draws near, I take a moment to reflect on its high points. For me, there were several, most notably, the publication of my first book (Getting Physics: Nature's Laws as a Guide to Life, link on the right side of the page, makes a great Christmas gift, wink wink). But, this year has been a rough one for me, particularly the past couple of months, for many reasons I will not elaborate on, but if I must list a theme, let's go with 'targeted attacks on minority communities'.

Of course, I am not alone. In these difficult moments, we need to try extra hard to be in the moment, and escape the weight of this general malaise. The classroom is a setting that can offer such an escape. Many students feel that the classroom is a place they would like to escape from, but consider this...

Many years ago, a student of mine was in crisis. I could see on their face that something was not right, and we had a chat. They said something that stuck with me: "The classroom is an escape, a brief respite from my troubles." I totally get that, particularly with physics, because physics does not care about the day we are having or whether there is peace in the Middle East. The laws of nature exist outside and above all of our troubles.

In a recent bout with COVID, I was watching too much Netflix, as one does (mostly movies I have already seen cause that's how I roll). I rewatched Jurassic World. There are two brothers who enter a theme park with dinosaurs. One's glee boils over, while the other stares at his phone. How can one not be completely in awe? That is how I feel when students get bored in physics class... Not that they all do, but of course, some do. Maybe most do some of the time? How can I know for sure?

At the front of the class, I get immersed in physics, and I get to spend time with a fun bunch of young adults. I get to escape things that exist outside the classroom. I want all of my students to experience the same feeling. I have spent my whole career figuring out how to do that while also maximizing their academic growth - and I still have much to learn.

Normally, I say goodbye to my students at the end of the year and inherit new groups in the Winter semester, and try again. But for my Mechanics class, there was a last-minute reshuffling, and no one could take this group of honours students of mine for their next course (Waves, Optics, and Modern Physics). In the shuffle, the course fell to me.

I now have this opportunity (has only happened twice before in my career) to teach the same body of students another course. I hope they will be happy to hear this news. My take on it, in general, is that it should be avoided. Students should see a discipline from many angles. Also, too much familiarity can be a problem. For example, students might think it is okay to break lab equipment cause "He's a nice guy, and he knows us," etc. Anyway, as I said, they are a fun bunch of young adults and I look forward to trying again. A second chance to get to know the Universe and escape our Earthly troubles in the process.

In the Light of Other Suns

2023-07-11T13:14:00.001-04:00

The Eighth Interstellar Symposium, entitled "In the Light of Other Suns" is underway this week at my alma mater, McGill University, in Montreal, Quebec. Hosted by the Interstellar Research Group and Professor Andrew Higgins, the space conference includes studies of various challenges associated with interstellar flight... and there are many!

Last night, I was fortunate enough to be in a sold out auditorium for a panel discussion amongst experts with varying backgrounds. The six hundred in attendance sat attentively as a wide range of questions were addressed, from "How much might the transit depicted in Avatar 2 cost?" to "Is it ethical to have a child on a planet that is not Earth, virtually guaranteeing that they will never set foot on their species' origin planet?" The answer to the former is on the order of petadollars (billions of billions of dollars), and the answer to the second is "We don't know."

The experts have no illusions that people will be travelling to Alpha Centauri in the coming decades. They anticipate microsatellites being propelled at relativistic speeds (>0.1c) to take pictures of exoplanets in that timeframe. Starships with people might be a hundred years away. So, why are distinguished professors studying them today?

The economic answer is that long term projects overcome incremental hurdles that enable spinoff technologies in the present. But there are so many more reasons, like the plain fact that we are an aspirational species. NASA technologist Les Johnson, irked by the question of economic returns associated with interstellar flight, posited that humans wanting to know things is reason enough (a comment that elicited enthusiastic applause).

Current engineering studies examine photonic propulsion and the highly reflective surfaces required to reach dizzying speeds. Others look at the stability of a tiny satellite's trajectory while being bombarded with photons or collisions with space dust when moving at some fraction of c.

I was expecting to hear more about Breakthrough Starshot, the aforementioned mission to snap photos of exoplanets and send them back to Earth. It seems that the interstellar community is becoming less focused on this one particular mission, instead looking at energy propulsion in a broader sense. The possibility of a one month transit to Mars was discussed; the spaceship would use a 1g acceleration for the first half of the trip (lasers pushing it from Earth) followed by a 1g deceleration during the second half (lasers pushing it from Mars). So ya, it would require laser arrays deployed on the Martian surface, but don't worry, studies have looked into the feasibility of that too.

Is it a space symposium for dreamers? Absolutely. But power to them (the photonic kind). A technical engineering conference that can fill a large auditorium is doing something right.

My first TV appearance!

2023-03-22T11:13:00.002-04:00

I'm excited to announce that I will be interviewed by Mutsumi Takahashi on CTV's Montreal noon newscast this coming Tuesday, March 28. We will discuss my book, Getting Physics, and how I use it to help make physics relatable for students.

I have done radio interviews before, but TV is a new thing for me. Looking forward to it!

A Thought About Teaching

2023-03-04T15:59:00.001-05:00

If we are born a seed, then when I meet students in college, they are plants with deep roots. On my best day, I can be a star that shines light on the garden before me, inspiring a direction in which to sprout. If that is not a good reason to get dressed in the morning and go to work, then I don't know what is.

My first book launch

2023-03-02T09:34:00.001-05:00

Next Thursday, March 3, 5:00 pm, I will be having my first book launch event at Vanier College (in the STEM Centre, D-301) for Getting Physics: Nature's Laws as a Guide to Life. I would love to see science enthusiasts there, particularly current and former students of mine.

I am thinking about how the event should run. I have been to book signings before and they always include some readings from the newly published book. My hope is that some of my current and former students could share some of the reading duties with me. After all, this book was written with them in mind. The schedule I envision is:

5:00 - 5:30 pm: hors d'ouevres and schmooze

5:30 - 6:00 pm: speeches and short readings from book

6:00 - 6:30 pm: book purchase and signing

My college issued a press release yesterday, so I am also hoping to make the rounds with local Montreal media.

It will be my pleasure to share this moment with readers of this blog who happen to live in my city. There will be no book tour, so I am contemplating ways to reach a wider audience. For now, I am starting with my stomping grounds, and seeing where it goes from there.

"Getting Physics" NOW AVAILABLE!

2023-01-20T07:43:00.002-05:00

After years of work, my first book, Getting Physics: Nature's Laws as a Guide to Life, is finally available. I will almost certainly never devote more time to any single project than I did this one. It is a labour of love, and I am so happy to share it with readers all around the world.

The link to purchase it through Amazon is here: GETTING PHYSICS.

I am not sure what else to write in this post. This blog is the place where I learned how to write about physics. Some of the contents of this book include paragraphs I wrote in 2010, the year The Engineer's Pulse was launched. I am feeling incredibly nostalgic right about now. The only thing that makes sense to me is to simply copy/paste the acknowledgement section of Getting Physics here:

Acknowledgements

Momentum for the manuscript began when eleven Vanier College students volunteered to read through a chapter or two and provide detailed comments. I want to thank Bastienne D.C., Peter D., Kamil C., Maria-Sara F., Quassandra D., Daniel M., Carolynn B., Will E., Alin B., Aashiha B., and Myriam L., because their feedback improved the book immensely.

There are two more experienced authors that helped point me in the right direction early on as I navigated the journey that is ‘publishing a book’. Thank you, Alex Rosenblatt and Brahm Canzer.

I must also thank Kristie Stuckey, whose keen eye and countless iterations led to the lovely figures contained herein.

Pearl Levine provided a round of editing that was much appreciated (she also bakes amazing brownies). Stef Caron used a fine comb and did a final, skillful pass through.

I have more colleagues at Vanier College to thank for their feedback and moral support along the way than I can fit here. I want to give a shout out to the Vanier College Physics Department, whose combined wisdom helped refine the lens through which I see physics. I also wish to thank Nicholas Park, Jean-François Brière, and Sameer Bhatnagar for reviewing portions of the book. Similarly, I have been encouraged to write about physics by many friends, like Jon, Corey, Lorne, Peter, Tom, Rob, Jer, Christian, and Jeff to name a few.

I have had the honor of teaching more than 1,500 students. My interactions with them helped shape me as an educator. Their curiosity and resilience through adversity inspired me to keep pushing forward in my career.

I would have little connection to academic content, nor any practical skills without the teacher interactions I had as a student. My fundamentals in math were solidified in college thanks to Denis Sevee and Frank Lovasco. Professor Andrew Higgins served as a model for how to communicate physics with gusto. Gerard Carrier and Alpha Ross showed me the ropes in the space industry, upping my technical engineering game. Finally, my mentor, Professor Arun Misra, taught me most of what I know about physics and engineering. He introduced me to orbital mechanics, space elevators, space conferences, and how to write technical papers; most importantly, he personified how to approach one’s career and human interactions with integrity. He has been my Mr. Miyagi.

Before any of this could happen, Mom, Dad, Jamie, you gave me a foundation upon which to build a life. I was brought up in this nurturing family, even though my mother is not exactly sure where her science author son emerged from.

Val. We were kids and then we grew into ourselves side by side. You are my anchor in this life. At this point, I suppose you get physics whether you like it or not.

Published in Scientific American!

2022-11-25T08:45:00.003-05:00

This morning marks a big moment in my career. I have long wished to be a popularizer of science, and there are few better venues for this than Scientific American. I had originally submitted a very technical article about space elevators to them, but they asked for something more 'fun', so I rewrote it. I am so pleased with the result: Space Elevators are Less Sci-Fi than you Think. I feel quite elated on this November morning.

The Journey that is 'Publishing a Book'

2022-08-05T13:54:00.002-04:00

Have you ever tried to publish a book? If yes, I wonder if your experience tested your might the way mine has. I have nearly crossed the finish line, but what a long and arduous road it has been (the publishing part, not the writing part). If you are thinking about publishing a book, perhaps the following bits of wisdom gleaned throughout my soul-crushing journey will be of some benefit to you.

There are two main avenues to publication: to work with a publishing house or to go about it independently. In the case of my forthcoming book, Getting Physics, I experienced both. That, in and of itself, is an indicator that things did not go smoothly...

My first mistake: Writing the book before choosing the avenue for publication

If you intend to publish with a publishing house, it is far more efficient to make a book proposal, which includes a synopsis, proposed table of contents, marketing ideas, and perhaps two chapters, before completing a manuscript. It turns out that even if you decide to publish independently, a book proposal is an excellent idea. If you will be your own boss, you ought to provide yourself with a roadmap that considers the big picture.

Having written the book first, I backtracked and prepared a book proposal, and this process led me to modify my manuscript. Armed with my book proposal, I now wished to find a publisher that was interested in my book.

I did some research, and found that the best way to get a good publisher is to get a literary agent. They work on your behalf, meeting with established publishers, many of whom only consider works that arrive via such an agent. It turns out that enticing a literary agent is about as hard as enticing a good publisher.

My second mistake: Having pride

I diligently prepared a list of literary agents that fit my work (non-fiction, popular science), got their contact info, and noted the package they wished to receive (usually a book proposal or a query, which is a much shorter synopsis of the project). I sent in five tailored packages and waited for a response. And waited. I checked my email and junk mail more often than I care to admit. Nothing.

I moved on from getting representation and began reaching out directly to publishers. Again, I researched publishing houses with non-fiction pop-sci experience. This time, I had a list of fifteen. I sent out packages in groups of three. I sometimes did get a reply, but it was never the green light I wanted. There were some helpful back and forth exchanges, including brief explanations of why my book was not the right fit. The main issue was that it was too lay to be a textbook, but too technical to be a lay book. Well, that is exactly what I was going for: a book that would be challenging but accessible for a physics novice, and a light, enjoyable read for seasoned physicists. I wrote it because that type of book did not exist, and it was the kind of thing my students needed; but the fact that it did not exist made publishers hesitant to sign a contract with a first-time science author not named Bill Nye.

With my pride swallowed and humble pie consumed, I remained committed to the project, and to working with a publishing house. This set me up for my biggest mistake.

My third mistake: Signing on with an unestablished publisher

A colleague told me about her friend who had recently published with a new publishing house who shall go nameless. I sent them a package and received a contract offer shortly thereafter. I examined the contract and sent it to an author friend, who saw no major red flags. I contacted one of the publisher's authors who spoke highly of his experience (his book was in sociology, not a natural science, but still, this gave me confidence to move forward). I signed the contract, and celebrated my victory.

I completed a bunch of paperwork and tailored my manuscript to the publisher's standards within a month. I recorded a promo video per their request. Then, I waited months with little contact. Eventually, they admitted that they could not find a content editor for science! In the meantime, they decided to copy-edit (format) the book, and worry about finding a content editor afterwards. The formatting process went on for months. The final look of the book was not bad, but getting there required so much input from me (they clearly did not know what they were doing). Months later, they still did not have a content editor for me, and I decided to part ways with them. Both the publisher and I wasted nearly 18 months that felt like 36 in this process that almost caused me to give up on the book entirely.

The only good thing to come out of all of this is that the publisher's ineptitude forced me to learn a lot about publishing books. This positioned me well to take on my latest (and, knock on wood, final) avenue for publication: KDP (Kindle Direct Publishing), which is run by Amazon. The support at KDL via both online tools and actual humans you can call and who call you back within minutes or hours, was incredible (feedback with publishers happens on timescales of weeks and months). Within weeks, the paperback was completed, and as I write, a proof hardcopy is on its way to my home by way of, well, Amazon.

I am not saying that all small publishers are bad, or that established ones only deal with established authors. Everyone's publication journey is unique, and not all are fiascos like the one I have detailed here. Still, I hope that some of this information will benefit another budding author on their road to publication.

My book has been a labor of love along a dirt road littered with shards of broken glass. I hope that many will enjoy it once it becomes available.

David Suzuki's 'The Sacred Balance'

2022-01-07T10:42:00.003-05:00

Like many, I have seen an uptick in my reading quota over the past couple of years. My diet has included about 25% fiction, 25% biography, and 50% science non-fiction. My favourite fiction was Matt Haig's The Midnight Library and my favourite non-fiction was probably David Suzuki's The Sacred Balance. I had never read any of Suzuki's work, and although this one is more than a decade old, it seemed to be his defining work, so I went with it.

Suzuki is a prominent figure in Canada; he has been a leader in the sustainability movement for most of my life. While my personal interest is in space exploration, there is no question that sustainability is the most pressing issue of our time.

The premise of the book is quite simple: while science is a powerful tool and a culmination of our collective creativity and curiosity, it has a tendency to be fragmented, failing to view ecosystems as a whole. The findings of science has led to short-term increases in standard of living, increasing lifespan and comfort, but it has come at a major cost to the prosperity of our species in the long-term. We are simply not thoughtful enough to use science conservatively; our economic system is based on unsustainable growth, and all political systems, thus far, have failed to prioritize the long-term. Science, when perverted by runaway capitalism, is nothing short of a slowly burning fire on the global scale with nothing to put it out. So, you know, this was a fun read in the midst of a global pandemic.

The thesis of the book is that we will not be able to control our planet with science for the foreseeable future. If we wish to have a foreseeable future, we need to model our behaviour after civilizations that have lived in harmony with the sustaining features of Earth for hundreds of years: namely, indigenous people. This does not mean we must abandon science and technology. It simply means we must refocus it. We must rethink our socio-political and economic systems; they must have sustainability sewed into their fabric. In a finite system, growth is madness. Growth is suicide.

The first half of the book focuses on the science of our sustaining systems and their interconnections: air, water, soil, solar energy, and biodiversity. It is in this latter chapter that the writing flourishes. A strong case is made that decrease in biodiversity hurts all species in the long run - it is a precursor to mass extinction. Biodiversity becomes a measure of the long-term prosperity of our species, like placing a stethoscope to our existence on this planet.

The second half of the book is where its strength lies. It talks about love and spirituality, the joys of being alive, the vitality that we are granted once our requirements of air, water, food, and warmth are met. The final chapter is about restoring balance, not with further attempts to engineer our planet, but by allowing the ecosystems of Earth time to fix themselves - by getting out of the way. We will need engineering to allow comfortable lives for our roughly eight billion population. But it must be long-term-focused. It must get out of the way. This final chapter is about how we can get there. It highlights stories of individuals, who become grassroot movements, who have come to effect macroscopic change. Their stories must become a beacon for us. They are truly motivational. This motivation will be crucial in the way forward.

Last semester, a colleague of mine taught a sustainability course. The experience left him disheartened because the students in the course did not believe humanity had the wherewithal to change. They lacked faith in our species, and who can blame them? In their lifetimes, world leaders have only set us in the wrong course, and these leaders often reflect the wants of the societies they represent. I understand my colleague's sadness. As a teacher, the students' morale is our morale. And frankly, if today's young people have thrown in the towel, we are indeed a lost species.

One shining light, from my point of view, has been some sweeping change that we have seen over the last couple of years, in our response to a very different existential crisis: COVID-19. Damn it! I almost completed an article without bringing it up! Maybe next time... But seriously, we saw a threat, and pivoted. It was not pretty, and not without hardship, but as a species confronting a dangerous threat, we tried to make changes to adapt to the situation.

Perhaps you have heard of the frog-in-the-pot analogy... A pandemic, to us, is like a frog that is dropped into a pot of boiling water. We are that frog, still trying to climb out, the hot droplets of water striking our tushies.

Our present situation, where our finite resources are being exacerbated, represents a different threat. In this one, we are a frog in slightly warm water that is continuously being warmed further. It will eventually boil. In this scenario, a frog would likely meet its demise. It would not instinctively react and jump out of the pot. But we have an advantage over the frog. We have tools, like a thermometer, and we understand the reasons for the warming of the water. We can forecast, with limited but reasonable accuracy, the rate of warming that will occur if conditions go unchanged. Armed with this, we can be smarter than a frog. We can evolve our thinking, act responsibly, and earn the right to wield the powerful tools that science has unleashed.

It is essential that we react to our biosphere crisis with the same resolve as we did the pandemic. We can do it. At the very least, we can try. But a sweeping response will only happen if a critical mass of people at all levels of society truly understand the severity of the situation. They need to embrace the obvious truth that this threat is every bit as serious as a pandemic. Its solutions are less scientifically complex than engineering a vaccine. We just need to learn to get out of the way. We need to exist within nature rather than attempt to manipulate it. It is less about new science than it is about smart design.

We all know that science and technology can be abused. We usually focus on the upside: agriculture nourishes the masses, electricity gives us light, warmth and comfort, and modern medicine reduces suffering and extends life. But these are the very things that have allowed our population to balloon. This larger population then demands the same kind of comfort, which means more brut engineering. While this ballooning sounds like the opposite of extinction, it has taken an unprecedented toll on our sustaining systems in the blink of an eye.

One way or another, this graph will come down. But how will that journey look? Will the descent entail pain and hardship? Will it end at zero? Or will we allow Earth's natural mechanisms the time needed to stabilize itself? Will we be here to see it happen? Will today's children come to know a world whose sacred balance has been restored? Countless humans today have not given up. Please be one of them.

As 2021 Winds Down in My Classroom

2021-12-07T15:17:00.002-05:00

As I rev up for that final push through exam season, I am reflecting on this past semester.

This semester followed more than one year of online learning. I felt relieved to know we were coming back. I could not spend another semester teaching from this chair in my home. The experience is ultimately deflating, because you know how ineffective it is for most students. Online learning was a necessary evil that I hope to never experience again. The one silver lining was observed very clearly yesterday morning as I cleared snow and ice off my car for the drive to the college.

This semester saw some very apprehensive students show up at the college. The incoming cohort was generally less prepared than usual for college. The second year science students, having spent their entire college education to that point online, were perhaps even more unprepared. College can feel overwhelming at times, even for students who had adequate high school preparation. This semester saw more students give up than I have ever seen in my 12 years as a teacher.

As midterm assessments were returned, some students were crushed, and stopped attending. I felt awful for them. I do not fault them for it. I look at it another way: realizing the adversity that all students have faced over the past couple of years leaves me feeling extra proud of the ones who have stuck around. They are the ones who will be sweating it out in three-hour exams next week. I hope they take pride in showing all they have learned.

As for me, I remain committed to what seems like my mission in life: to help people 'get physics'. I look forward to the years ahead spent in the classroom. Career-wise, I am also excited about two things happening outside the classroom.

Over the past week, SERG (the Space Elevator Research Group) has reformed. It includes three Vanier College students. Over the coming months, we will be undertaking a new space elevator dynamical study. It will involve the addition of a station at the geosynchronous altitude. I am excited for that to get underway. More updates to come on this project in 2022.

And then, there is my book, Getting Physics. The publication process has been, well, lengthy, thus far. I was hoping it would be published by end of 2021. At this point, I will settle for sometime in 2022. I appreciate all of the words of encouragement I have received via email and LinkedIn. I am so excited to get this book into the hands of readers in the near future.

After years of teaching, it has become evident to me that you do not need to be a physicist to get physics. Physicists will dive deeper than the rest of us, but there is much depth to physics even at the surface. The fundamentals of physics are accessible to nearly anyone who wants to know them. Ask my students this semester, who can describe all kinds of phenomena, from a car crash to a vibrating guitar string. They are only beginning their journey into the sciences. They are not experts yet, but the seeds have been planted.

I want to wish you all a wonderful holiday season and much happiness in 2022.

Disrupting Earth's Orbital Mechanics

2021-11-01T17:37:00.000-04:00

After today's physics class, which involved orbital mechanics, I began thinking about ways in which humans could affect the Earth's spin rate or its path around the Sun.

Jumping all at once:

If all humans congregated at one place on Earth (7+ billion people in one city, while maintaining social distancing, of course), and then jumped simultaneously, there would be some repercussions. The energy of all that mass shifting in a short time could lead to an Earthquake, for example. But, that is not the sort of effect I am interested in.

Would Earth's path around the Sun be affected? The answer is, surprisingly, not in the slightest. The problem is that we would eventually land back where we started. The net mass of the system consisting of Earth and us will not have changed. As we are part of the total system that is in orbit, the forces exchanged during both the jump and landing would be internal to that system. It is not possible to change the system's velocity without a force exchange with something external to the system. For example, an asteroid collision could have some small effect on the Earth's orbit.

Running all at once:

OK. So, jumping failed. Maybe by running, we can impact the planet's spin rate. Imagine that we (the human population) were to gather somewhere on the equator, like Singapore. We collectively decide that we wish to change the length of a day on this planet. We decide to run along the direction of the Earth's spin with the expectation that it might slow the rotation down (there are not enough hours in a day, they say).

With our first step, we propel ourselves forward (the Earth pushes us in the direction we move via static friction), so we impart an equal static friction onto the surface of Earth in the opposite direction. However, every subsequent time that our foot strikes the ground, it slows us down before speeding us up again. In fact, if we maintain our jogging speed, each step results in a net linear impulse of zero (on us and the Earth), which means that each step has zero net effect on the angular momentum of either.

It seems we suffer from the same problem as we did while jumping. Our initial acceleration from rest gives a tiny net angular impulse to Earth, but it will undo itself when we decelerate, just as our jump was only temporary in the previous scenario.

The only way to accomplish either of the intended effects (disrupt orbital path or spin rate) is to do something more permanent, like sending payloads to space. These do indeed impart small net impulses onto the Earth. I could calculate their magnitudes, but I don't feel like it.

Blowing up the planet:

Frustrated with our wasted efforts, we decide to blow the planet up from the inside. It splits into two halves. Each hemisphere will orbit the Sun, but the precise orbit of each half will depend on the direction in which the planet splits apart. Regardless, the Earth gets the last laugh... The center of mass consisting of each of the hemispheres will remain in the original orbit, because again, the explosion is ultimately an exchange of forces that are internal to the system.

A Goldilocks Universe

2021-07-05T12:50:00.011-04:00

Anyone with experience in astronomy has encountered the term 'Goldilocks planet'. It pertains to a planet that is not too near a star, nor too far, such that it may have liquid water on the surface. Many scientists believe that this is a necessary pre-cursor for life. Earth is the only Goldilocks planet in our solar system, but exoplanet searches have identified others across this galaxy.

This morning I was thinking about the Universe, and noting that there could be no Goldilocks planets without, what we might call 'Goldilocks stars'. I would define a Goldilocks star as one that has a main sequence that endures for billions of years at the least. There are countless such stars in our galaxy.

Why are billions of years of stable star output important? It is because such is the timeframe that it takes for the development of life (itself an unlikely event) on a planet (which itself may take hundreds of millions of years to develop into a potential host for life).

A star's main sequence describes its stable state where the gravity that holds it together is in balance with the internal pressure that pushes it outward. It is achieved during the period of time when the core of the star is largely a mass of protons zooming about (these protons are denoted as H-1, as they are hydrogen isotopes that lack a neutron, known as 'protium' as they are effectively just protons). Energy is created via nuclear fusion when these protons collide and enter into what is known as the unfortunately named 'p-p cycle'.

A complete p-p cycle is a complex series of nuclear fusion reactions that eventually convert six protons into two protons and one Helium atom. Each link in the fusion chain spits out other matter including positrons, neutrinos, and gamma particles. Most importantly, the fusion reaction releases thermal energy because the nuclear by-products have less mass than the nuclear fuel - the fusion process produces energy E in the amount of dm multiplied by the speed of light squared (Einstein's uber famous equation) where dm is the quantity of annihilated mass.

The big picture is far less complex than the details: hydrogen fuel converts to helium and releases energy at a specified rate until it runs out. The amount of time that this dance will play out for is determined by just one thing: the star's mass.

Red Dwarfs are small stars and are the most common; they can burn for trillions of years. Yellow Dwarfs (like the Sun) are medium-sized and less common but not uncommon; these burn for billions of years. Supergiants are far more massive than the Sun and are far less common; these burn for just millions of years before they exhaust their fuel supply.

Given the brief period of time (in cosmological terms) that Supergiants undergo their main sequence, it is unlikely that its planets can ever harbor life. We can deem these stars too big. We do not yet know whether Red Dwarfs can sustain life on the planets that orbit them. These stars might be too small. We do know for certain that planets orbiting Yellow Dwarfs can harbor life (we know of one clear example of this). These stars, it seems, are just right: Goldilocks stars.

But it all comes back to that p-p cycle. The rate at which our Sun burns through its fuel depends upon the probability that a p-p cycle can be completed. Smashing two protons (H-1) together does not guarantee that a deuteron (H-2) will be synthesized (step one in the p-p cycle)... Far from it! It is actually extremely unlikely. The probability that it will occur is on the order of 1 in 10 to the power of 26! The reason that the Sun produces energy at such a high rate is that despite the low fusion rate, there are some 10 to the power of 57 protons zooming about.

It is the 1 in 10 to the 26 rate that confounds me. I mean, like, why that rate? Each proton-proton collision is a quantum event. The particular fusion rate seems so random, arbitrary even. But it is ultimately critical to our existence. If this rate were, say, ten times higher than it is, our Sun would have burned out long before life emerged on this planet.

Physics reveals many instances where the conditions of the Universe, its matter and the laws that govern how it interacts, seem to be just right. If the strong nuclear force that binds the nucleus of an atom were slightly weaker, the electrostatic repulsion of protons would exceed it and prevent the existence of any atom not called Hydrogen. No atomic variety means no life, just as no long-burning stars means no life.

One can imagine a universe not so perfectly tuned; a universe where life is impossible instead of improbable. We may live on a Goldilocks planet that orbits a Goldilocks star, but if we widen our gaze, we see that we reside in a Goldilocks universe. Not that it matters, but it is a funny coincidence that like Goldilocks herself, I ate porridge for breakfast today. I mixed it with leftover brownies. It became just right.

AATIP Reveals Compelling Videos of UFOs

2021-06-19T09:01:00.003-04:00

Some weeks ago, as my class was discovering notions of relativity, a student asked what I thought of the bizarre videos that were making its rounds on the internet - they reveal what appears to be some kind of unusual aerial vehicle. I watched these black and white videos with curiosity. In the background, you can hear some excited voices expressing genuine confusion about what they are witnessing. With final exams looming and little free time, I did not pursue this rabbit hole any further. Then weeks later, a friend we'll call 'Phil', asked what I thought about the UFOs.

Tom is a staunch believer in the scientific method and a skeptic when it comes to conspiracies and the like. But he found these videos to be very compelling. He informed me about Luis Elizondo and the Advanced Aerospace Threat Identification Program (AATIP) and suggested I watch his recent interviews. I did. I also came across a clip of Barack Obama giving credence to the notion that the highest levels of American intelligence have come across aerial vehicles whose origins confound them. It appears that AATIP is indeed a genuine Pentagon program and they will issue an official response to the aforementioned videos.

I impressed upon Phil that I am typically not drawn into stories of this nature due to the extreme unlikelihood of alien visitation. However, if these videos were real artifacts, free of manipulations, they reveal technology that is far beyond current human capability. The aerial vehicle in the videos:

1. Has no visible means of propulsion and whatever does propel it shows no sign of interacting with the environment.

2. Transfers from air to water without disturbing the water.

3. Banks extremely sharp turns at impossibly high speeds.

Let us, for instance, analyze point 3. The vehicle is tracked at speeds in excess of Mach 5 (five times the speed of sound in air, so about 1,650 m/s). In order to not experience violent accelerations in excess of 5g (about 50 m/s/s), the minimum radius that its circular path would require is 36 km! Points 1 and 2 are even more bewildering.

If these videos are authentic, how did the vehicles get here undetected by our radio astronomers? Elizondo theorizes they emerged from the deep ocean. Phil asked me where we should purchase our aluminum hats.

Passing on the hats for the moment, I went to the library later that day, and returned home with They Are Already Here: UFO Culture and Why we See Saucers, by Sarah Scoles. The book is a historical account of the human obsession with UFOs and the possibility of alien intelligence, from Roswell and Area 51 to AATIP. The title to the book is misleading: the author confides on the last pages that she remains unconvinced that any interplanetary intelligence has ever visited Earth, and that the plethora of reported human encounters with aliens are either honest mistakes or fabrications.

I am interested in honest mistakes, as they force us to apply the scientific method within this thought-provoking context. These range from explainable celestial events, to high-tech military operations, and a wide range of optical illusions. I also understand and do not fault claims of UFOs that are entirely psychological, whether they be drug-induced or convincing dreams.

On the other hand, fabrications offend me. They are an affront to my senses. They degrade the entire process of discovery. Muddying the evidence, manipulating the data, unfalsifiable claims masked as truths... These acts of dishonesty, whatever their motivation, highlight the fly in the ointment, which is human corruption. Such acts of deceit serve only to spoil the earnest endeavor of identifying UFOs. One key take-away from Scoles' book is that distinguishing genuine science from hoaxes is half the battle in the search for alien intelligence.

When it comes to the matter of extra-terrestrials, we must be extra skeptical of information emanating from sources who have a vested interest in making the first human contact with them. One such player is Robert Bigelow, a wealthy American who has initiated numerous 'scientific teams' whose primary outputs have been UFO fabrications. When I discovered that Bigelow has a connection to AATIP, I began to doubt the authenticity of the internet videos.

It is improbable that we have been or will ever be visited by interplanetary beings during our species' tenure on this pale blue dot. The chances that intelligent life exists in our neighborhood of this galaxy during the small window of time comprising human existence are very low. But not zero. And that is what distinguishes the topic of aliens from other human obsessions, like paranormal activity. The former is entirely conceivable according to our current understanding of nature.

Evidence that confirms the existence of aliens would cause a dramatic shift in our understanding of the universe and our place in it. That is why this conversation is so alluring.

I await the Pentagon's response to the videos that have captured the attention of so many. If their assessment does not support the alien intelligence theory (and I highly doubt that it will), conspiracy-theorists will be unmoved. Government history does include cover-ups, which merely confirms the general prevalence of human weakness. This history of dishonesty injects doubt into the UFO conversation.

I will not be buying an Aluminum hat just yet.

Enforced Rotation of Tarzan Rope (Solution)

2021-06-08T09:16:00.007-04:00

The semester has ended, and alas, nobody posted a solution to the difficult problem I posed months ago (see problem here). In short, we have a rope that is suspended from the top and is being moved along a circular path in the horizontal plane with constant angular velocity. Aerodynamic effects shall be neglected. We are seeking a lateral deflection function. Here is my solution...

With a problem such as this, we must begin with a physical model. My hand drawing is seen below (I apologize for the crude sketch, but the summer me exerts less effort):

The solid blue line represents the rope whose profile we aim to determine. At some location (x, y), we will apply Newton's second law to a single mass element dm. My free body diagram is on the right side. There are two external forces acting on the element; one is real and the other, a pseudo-force. The real force, dFg, is gravitational, while the centrifugal load, dFc, is a pseudo-force as it is effectively an inertial term. Finally, tension acts internally, pulling this element in both directions tangent to the rope's profile at (x, y). The upward pointing tension is (correctly) assumed slightly higher than the downward one, by some amount dT. One useful, though limiting facet of the assumed model, is that, at a given vertical location x, each element simply displaces horizontally - in reality, it also shifts up vertically, ever so slightly. This simplification allows an elegant solution, but whose accuracy is limited as we shall see.

Applying Newton's second law to that element on both axes, we get:

dFc = dTsinθ (1)

dFg = dTcosθ (2)

We can express the elemental forces as:

dFc = dm(ω²y) (3)

dFg = dm(g) (4)

The angular velocity of the enforced circular motion is denoted by ω. If we divide equation 1 by equation 2 and then divide equation 3 by equation 4, we get the relationship

tanθ = ω²y/g (5)

The key realization to move forward is that the derivative dy/dx = tanθ. This yields the governing equation:

dy/dx = ω²y/g (6)

The particular solution to equation 6, after having applied the boundary condition y(0) = R₀, can now be found. The radius of the enforced circular path, is given by:

y(x) = R₀exp(xω²/g) (7)

This solution is quite interesting. We first notice that the density and area of cross-section of the rope have no effect on the shape it takes. This is not surprising because both external forces were proportional to the elemental mass. The more important takeaway here is that the lateral deflection becomes exponential. The faster we spin the top of the rope, the more dramatic the curve. This makes sense, but there is a serious flaw: the rope has a finite length. As this function is exponential, there is no limit to the lateral deflection it describes. As the imposed angular velocity increases, the lateral deflection can quickly become greater than the total length of the rope, which is physically impossible.

I suspect that I ran into this problem because, in my original model, I neglected the gain in altitude that a particle driven laterally inevitably experiences. For fun, I included this effect in a subsequent attempt. After a page of work, I saw that numerical tools would be required to solve. Again, it's summer, and I am content to move on and not pursue this problem further, especially when a closed solution appears impossible.

Equation 7 may be a good approximation of the rope's profile for fairly slow rotation rates. An experiment is difficult to conduct for multiple reasons. While air effects lead to a three dimensional profile, so too would inertial effects when it comes to establishing planar motion. In principle, it may be possible to enforce the theoretical equilibrium configuration as well as a uniform angular velocity for all string elements, but it is not practical. Failure to do this would inevitably lead to a helical 3D profile.

You may be thinking I did all that work for nothing. It is important to realize that simplified approaches teach us a lot about complex problems. They give confidence to the more strenuous, complex solutions that follow them.

And now, out of my cave. Summer beckons.

Enforced Rotation of Tarzan Rope (Problem)

2021-01-24T18:09:00.002-05:00

I had so much fun with the rope problem I posted to start off 2021 (which was subsequently solved by Anthony Attia - see his elegant solution here), that I want to continue to explore this theme. While that problem seemed tough (seeking the steady state profile of a uniform rope pinned at its top end and suspended vertically in a uniform horizontal wind), it turned out to be fairly simple. It was almost disappointing. To remedy the situation, consider an even more intriguing problem...

Imagine a Tarzan rope (bulk density 'p') that you suspend vertically in uniform surface gravity 'g'. You then take the top end of the rope with length 'L' and move it with uniform circular motion in the horizontal plane (radius 'R' and angular frequency 'w'). Ignoring aerodynamic effects (because that would cause a 3D problem and have no clean analytical solution), what profile will the rope assume? That is, if we froze the video at any given instant, what lateral deflection function, y(x), describes the rope's shape? Treat the rope like a string (cannot support shear loads).

I spent some time on the problem, and it turns out to be even more interesting that I expected. I will not give any hints this time. I am curious to see if anyone will post a solution. If you do, please provide a description of how you did it.

I am excited to share my solution, but I will be patient, and see what, if anything, gets submitted here.

A Tarzan Rope in the Wind (Solution)

2021-01-23T11:50:00.004-05:00

This is very exciting: a former student of mine, Anthony Attia, has submitted a solution to the Tarzan rope problem I posted some weeks ago. Anthony was in my Mechanics class at Vanier College in 2016. He is now pursuing undergraduate studies in mechanical engineering and simultaneously doing a stage at my former employer, MDA Space.

As is the case with some students, Anthony and I have stayed in touch since he graduated from college. This post, however, is the first one in more than ten years of this blog's existence that someone other than me has written; it is about time. Watch as Anthony analyzes a uniform rope, pinned at the top and vertically suspended, subjected to a horizontal uniform wind.

The following text appears here with Anthony Attia's consent:

___________________________________________________________________________________

When faced with a complex physical phenomenon, it is quite common to simplify the problem to a point where an analytical solution can be formulated. The simplification is done by stating assumptions throughout the approach. The more assumptions we take, the more likely our approximated answer will diverge from the true value. As students of science, it is our duty to ensure that we are equipped with enough knowledge to apply the proper assumptions.

Tarzan’s rope problem can be as complex as we want it to be. We can treat the rope as either flexible or rigid, we can treat the wind force as a function of time or a constant, we can consider the effects of cold temperature on the characteristic properties of air or we can neglect them. For the sake of maintaining my sanity and that of the reader’s, we shall treat the rope as a pinned rigid body who is subjected to a constant drag force that is acting in the horizontal direction. An important fact about assumptions is that there cannot be an incorrect one per say, however, every single one of them must be justified.

In my preliminary analysis, I will assume the rope to be rigid, effectively assuming that the profile of the rope will be linear when displaced. Generally, this assumption would not be valid with a rope, but I will make it anyway and check the extent to which it was good later.

With that in mind, we can begin trying to find the velocity of the wind, by relating the drag force FD and the weight W. Consider the model below, which depicts the scenario:

Given that the net drag force is acting on the center of gravity in the horizontal direction and the weight is acting in the vertical direction, the ratio of these forces, FD/W, ends up being equal to tan(θ). We can take the sum of all torques about the pin and put them equal to zero. Then, using the following definitions, we may express the wind speed as a function of the other parameters.

Surface gravity: g

Air density: p

Wind speed: V

Rope angle: θ

Rope mass: m

Rope diameter: d

Rope length: L

Rope shape (cylinder) coefficient of drag: Cd

The wind speed is then given by:

Knowing this, we may begin computations to determine the wind speed that causes a specific rope deflection. Assuming some reasonable 'Tarzan rope' values, it takes a 15 m/s wind to rotate the rope by 30°. This seems reasonable. But, we can only feel so much confidence in this result, as it is based on an assumption that may not be justifiable.

Say, however, that we now want to treat the rope as a flexible body; how would we proceed? Before answering that question, we must properly understand the behavior of weight and drag. In the previous figure, the drag force was lumped into a single vector whose line of action passes through the center of mass of the rope. Let us do a quick thought experiment: if we were walking headwind, would our entire body feel pushed by the drag force or just a single point? The answer is the former. So, why did we draw a single vector? That vector is actually the resultant or net drag force acting on the rope. If we were to properly illustrate the aerodynamic force that the body is subjected to, we would have to draw many smaller vectors that are acting on the entire exposed surface. These types of forces are called distributed load: though they act on every point of the body, we may sometimes use a single vector to represent the resulting effect (note that gravity is similarly distributed and then a resultant is used). Every segment of the rope has a mass equal to dm and the sum of all segment masses will yield the total mass m. Now, to solve the flexible body problem, we must assess a differential segment dm that is exposed to a differential drag of dFd by drawing its free body diagram.

Newton’s second law in x and in y yields:

These equations simplify to:

Equalizing the two equation we get:

It is evident that the equation obtained for the flexible body problem is the same as the rigid body problem, however, it is in a differential form. To remove the differentials, we must apply an integrating operator to the equation. If we do so, the same expression linking the angle to the wind speed is obtained.

We conclude that both approaches lead to the same answer, but one requires an understanding of calculus, whilst the other requires only an understanding of mechanics. As one of my professors used to say, the simplest solution is often the best solution!

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It gives me much pride to see a former student of mine express himself as he does here. I get the same result on my end as that which he found. The reason that the rigid body assumption works is because, due to the symmetry of the scenario, the uniformity of the fields and rope, the rope's profile must be linear.

In this problem, we have the weight force and the drag force. They act vertically, and horizontally, respectively, onto each element. While weight acts on dm elements, and drag acts on dA elements, both are uniform: we may think of each as a uniform field. Effectively, they combine to form a uniform net field, and the rope simply aligns itself with it. Though I initially thought the rope would have some curvature, it does not. I am almost disappointed that the result is so simple. I will try to pose a problem that has a stranger result in my next post.

Still, what I really want to emphasize here, is something greater than the problem itself. I am thrilled that The Engineer's Pulse just had its first guest writer; he happens to be a fine engineer in the making.

A Tarzan Rope in the Wind (Problem)

2020-12-26T11:30:00.006-05:00

With all of my grades entered, my mind can turn off for two weeks. In my case, that means exploring my curiosity. Today, that resulted in a fascinating mechanics problem.

My kids have a Tarzan rope in the backyard - a rope suspended vertically and hanging freely. I noticed this morning that it had been displaced significantly by the wind: it was now draped over a swing that hangs nearby. "That must have been some wind," I thought. Rope has a small ratio of surface area to mass, which means it should not be overly affected by aerodynamic drag forces. With some physics, I should be able to estimate the minimum speed of last night's wind.

To make the exercise worthwhile, I have no intention of simply solving a numerical problem: boring. Instead, I will solve a generalized problem before specifying any parameters. Before doing so, I will make some assumptions that will hopefully render the problem to one that can be solved without numerical software.

I will assume that the wind is lateral and constant. This may lead to an overestimate of the wind, because it is possible that some sort of driving frequency was present in the wind, causing the fundamental mode of the rope to resonate somewhat. Still, it is probably a fair assumption. Also, the fact that the wind force is not time variant will reduce the governing dynamics from what could have been a partial differential equation to an ordinary one. This is because the lateral displacement of the rope (y) varies along the vertical rope's length (x). A time-varying displacement would make the solution vary according to y(x,t), a multivariable function. Now, I can begin my search for the single variable function, y(x). I will also assume what appears to be true: the rope is uniform in terms of its properties and cross-sectional geometry across its whole length.

At this point I could probably Google "steady-state lateral deformation of a vertically suspended uniform rope exposed to a uniform and constant lateral wind", but I strongly doubt anything useful will turn up. So, because I can (I hope) solve this problem, I am diving into it head first.

Yup, it's boxing day, but instead of looking for deals on stuff, I am entertaining myself for free as my wife shakes her head (well, she doesn't, but that is only because she thinks I am up to something more important).

Before beginning this analysis, I must determine what approach to take. It is clear that with a constant wind speed at all locations of the rope at all times, the rope will reach a steady state y(x). So, I am in search of an equilibrium position. This simplifies things considerably from a typical first principles analysis. Rather than applying Newton's second law for all of the infinitesimally small segments of rope, dx, I can do this using the first law. That is because acceleration has been removed from the scenario.

I could do a quick first pass using an assumed modes shortcut. If I assume that the shape of the rope will follow a specific y(x), I could quickly establish a single algebraic equation in which wind speed is the only unknown. Here, I would effectively be starting with an assumed solution, but if my guessed shape happens to be good, the answer it gives could be surprisingly accurate. It is a good moment to pause and ask ourselves the following question: If we were forced to assume the shape that a constant wind would impose upon the freely suspended rope, what mathematical function might it follow?

Four possibilities immediately come to mind:

(1) Linear

(2) 1/4 sine wave

(3) Some sort of polynomial

(4) Some sort of exponential

I will not reveal here which of the above options my intuition leans towards. I will leave that as a fun mental exercise for the reader. I will dissect each of the above options in my solutions post.

Alternatively, I could use a more generalized approach - one that requires no shape assumption. The downside here would be that an ordinary differential equation would require solving. It would probably be solvable analytically, without the use of numerical tools. The type of y(x) function that would result would either confirm or negate the choice of assumed function used in the shortcut approach described above. I guess I should be rigorous, and explore both options. I could then note the extent to which the quicker method is valid.

I suppose this is where I leave you, for now. If you are a mechanics savvy reader and are up to the challenge, feel free to post your solution for y(x) in the comments (you can use any approach you like, but please state the one used). To ensure we use the same variables, express your y(x) in terms of the following variables:

Surface gravity: g

Air density: p

Wind speed: v

Rope mass: M

Rope diameter: D

Rope length: L

Rope elastic modulus: E

Rope shear modulus: G

Rope shape (cylinder) coefficient of drag: Cd

It is likely than one or more of the above parameters will not appear in your solution for y(x). It is also possible that some additional assumption on your part will be required, though at this time I cannot think of one.

Alright, now for the hard part, if I do not get overwhelmed by laziness: working out the detailed solutions. See you on the other side of 2020.

The Smoke of Wildfires Travels to Canada

2020-11-19T14:26:00.010-05:00

The 2020 wildfires in California have devastated parts of that state, but they also serve as a symbol for the socio-political fire that is consuming America. One clear similarity between the two scenarios is that the current environmental conditions favour devastation. The likelihood of the physical fires increases as the globe warms, and high winds paired with low precipitation spurn it onward. The socio-political fire that rages on in the United States is a direct result of a tribalistic political environment, which threatens to overthrow democracy in that country.

There are, of course, some important differences between how these fires are being handled. The physical fires are combatted by waterbombers and firefighters. Fire chiefs have done everything in their power to prevent its spread. The divisions in the United States – the deep discord among its citizens – has been and continues to be exacerbated by the outgoing President. The fire chief is stoking the fire as he contemplates his next move. We are witnessing the fall of Rome.

As Canadians, I may consider myself a passive observer of the 24/7 drama channels, like CNN. But I have good reason for staying tuned, despite its obvious negative effects on my mental health. There are serious existential risks to our species that we must face, from the aforementioned climate change, to the current (and next) pandemic. Neither of these threats lead to our extinction in the short term, but they require our serious attention to limit their harmful effects in the long term.

Various branches of government must work alongside scientists to combat these fires from spreading. But instead of that, the leader (did I mention outgoing?) of the American government is questioning the expertise of the scientists, and even worse, causing his mob of supporters to doubt scientists. That is like halting efforts to stop the fires in California because we distrust that water molecules consist of two atoms of Hydrogen and one of Oxygen (I can actually imagine President Trump arguing that the Oxygen atom helps the fire breath as his minions nod their heads). Worse still, the smoke that blows from his mouth travels around the world, infecting non-Americans as well.

Assuming that President-elect Joe Biden is indeed sworn into office in January, the next question becomes: Can America reassert its place in the world, become a voice of reason, and help us homo sapiens become responsible custodians of Earth?

Perhaps Canadians can instead ask themselves: "What can we do to help make this possible?" I have a few suggestions. Let's:

1) Be our best selves. We need not enter into Facebook yelling contests with conspiracy theorists. Let the FBI worry about them. Just act kindly - be respectful and act with integrity.

2) Promote the virtues of democracy and show up to vote when it is our turn. We can also encourage our leaders to be their best selves.

3) Clean our own house. Canada is great but it is far from perfect. We must lead by example and do what is undeniably right. We must continue to strive for equality across race and gender.

4) Act responsibly towards the environment as individuals and ask our leaders to hold corporations and institutions to this same standard.

Who knows? The age of reason and enlightenment may not be out of reach. Getting there, however, will mean fighting back against the many fires that threaten to consume us. It means trusting the experts who have earned such distinction. It means electing officials who serve our best interests. Most of all, it means thinking locally and globally; it is not and has never been a choice between one or the other. A fire anywhere on this planet is a fire everywhere on this planet; we have just one planet.

I fear that Americans may be so divided that no leader can sew the country back together in four or even eight years. I mitigate this fear by turning off CNN and going for a walk.

The Benefits of a Decade Blogging

2020-11-02T15:53:00.004-05:00

I founded this blog in October, 2010, which feels like an eternity ago.

After ten years of blogging, I can speak to the positive impacts it has had on my career. Though I originally started the blog as an outlet for my ideas on science and engineering, it quickly evolved into a space where I write for my students; after all, I became a physics professor at Vanier College in 2010 also.

Blogging has:

(1) Helped me consolidate my own ideas

(2) Made me a better teacher

(3) Given me a bank of topical content at the right level to pass on to my students (incidentally, this has become a cornerstone of my teaching approach, whereby new content is introduced before class, conceptually - students then write their reflections and submit them - and I then assign their best questions back to them so they may discuss them in groups)

(4) Been a launchpad to some speaking and radio gigs

(5) Made me a better writer

This last benefit has enabled me to produce a manuscript for my first book about the fundamentals of physics. A couple of publishers have shown some interest in it recently. I am hopeful to sign a publishing deal sometime in 2021.

Ah, 2010 was long ago indeed. The blog has aged with me, but also my children - my eldest had just turned one when I wrote my first post, which was fittingly entitled "My Daughter the Physicist". Reminiscing further, humanity seemed in better shape then. Two years into President Obama's first term, there was reason for optimism. I still remain hopeful that we can right the fragile ship on which we sail, but along with many of you, I am growing worried of the future (like, two days in the future, when a racist, misogynistic, reason-defying narcissist is hoping to see his time in the White House extended by four more years).

I pray that in 2030, humanity will have found its stride, and have become responsible custodians of this planet. It is within our capability. Until then, I will continue to write, for there is indeed a sixth benefit to doing so: it is so much fun.