Peer Instruction Beats out Lecturing by Factor of Two

In the early 1990s, Harvard physics professor, Eric Mazur, was teaching advanced physics courses to bright students. He gave exciting lectures, complete with compelling, thought-provoking demonstrations.  He was praised by students for his clarity in delivering the material.  Then, something unusual happened.

Mazur set out to gauge the effectiveness of his teaching scientifically.  He employed a standardized test known as the Force Concept Inventory (FCI) to assess his students' conceptual understanding of mechanics, before and after teaching his courses.  The results surprised him.

He was not surprised that most students entering his class came in with a relatively weak understanding of mechanics.  He was, however, astounded that after having taken his mechanics course, his students performed only marginally better on the FCI.  Mazur was dumbfounded.  In the years that followed, he set out to determine, scientifically, what constitutes effective pedagogy for science education.

Traditional lectures, where a teacher communicates information to students who dutifully take note of the content, are fairly useless.  At its best, such an approach can be entertaining, but not cognitively stimulating for students.  In fact, cognitive function in students while attending a lecture (even a good one) has been shown to be lower than while sleeping.  In this context, who can fault a student for sleeping through a lecture?

Mechanics in an Elevator

Though the title of this article is less catchy than the Aerosmith classic rock tune that it alludes to, an elevator is, nonetheless, an excellent place to solidify one's understanding of mechanics.

I rode up an elevator from the ground level to the eighth floor of a condo building long ago with my daughter, who was three at the time, to visit her great-grandmother.  As we approached our destination, and the elevator began to slow down, my daughter asked, "Daddy, are we going down?"

"Amazing," I thought, "kids can sense acceleration, and have already developed the same false preconceptions about it that they bring to their introductory mechanics courses."

It makes sense that people, and all animals for that matter, can sense acceleration, as we live in a dynamic world, and acceleration, which is the rate of change of velocity, may be thought of as the forecaster for motion.  If one can detect one's own acceleration, then one can accurately predict one's future position (provided one knows one's own current position and velocity with accuracy).

Hybrid Cars Finally Worth Considering

Until recently, I harbored mixed feelings about hybrid cars.  On the one hand, they decreased fuel consumption significantly, while on the other, they were very expensive, and entailed more parts than a standard combustion engine car, which translates to more maintenance costs down the road.  I would never have recommended that anyone buy one.  At best, an environmentally conscious consumer could undertake a lease, pay a bit more in total costs, but feel they'd done a small service for the atmosphere.

In 2012, it seems to me that hybrids have rounded the bend, and crossed a very significant threshold.  In some cases, it appears that the purchase of a hybrid is, in addition to environmentally considerate, cost beneficial.

A new technology like hybrids had a lot going against it in the early going.  Purchase prices were high since production quantities were low and R&D costs were significant.  Also, new technologies are less reliable than tried and true ones; they have not been through the iterations that come through multiple generations of development.

Life is Just One Big Experiment

This coming Friday, a friend and I will be performing music at a bar (pop, rock, reggae).  It will be our first show together.  Our band is shamelessly called, "The Acoustic Love Explosion."  We have been practicing together for a few months.

I will be playing the drums, he the guitar, and we will both be singing.  I have never witnessed a performance having this musical arrangement before, and am curious to see how the audience will react to it.  In particular, I wonder if the lack of a bass guitar will be noticable, and whether the sound will feel empty.  This first show really feels like an experiment - one that, if successful, will spawn similar ones in the future.



Sometimes, life, from the moment we are born until the moment we die, feels like a giant series of experiments.  Some might prefer to substitute the word "experiments" with "experiences", but really, the difference is quite subtle.  An experiment is possibly even more accurate, as it implies that some lesson will be learned, and retained in our memory.

Airplanes That Seem to Hover

Last year I posted an article about the fundamental principles behind how a subsonic aircraft works.  In summary, an airplane takes off once a critical speed is reached: the greater the speed of the wings relative to the air being cut by them, the greater the pressure difference between the air on the top and bottom of the wings, and the greater the lift force.

Now, I would like to address a particular concern about airplanes that some of my students have had.  Have you ever looked up at an airplane, and had the impression that it was barely moving?

Helicopters, hot air balloons, and some supersonic aircrafts possess the ability to hover, but subsonic aircrafts do not.  As already mentioned, the only reason that a commercial plane can maintain a given altitude is because it is moving horizontally with respect to the air around it.

So, what is going on here?  I too have looked up at aircrafts as they descend and have remarked, on occasion, that the plane seems to be moving at a snail's pace.  Sometimes an airplane flies above me as I cruise along the highway, and my impression is that I am in fact moving faster than it relative to the ground.  Is it an optical illusion?  Let us investigate.

The Wondrous Night Sky

When my daughter recites twinkle, twinkle, little star, I am tempted to answer her question regarding what they are: "Giant collections of particles moving in all directions colliding into one another at high speeds forming larger particles in fusion reactions that give off heat and light..."  And then I remember that she turns three this summer.

I got to thinking about stars when a couple of callers rang me up the other day on my call-in show.  OK, I don't have a call-in show.  It was just a couple of friends calling me at home with questions about stars.  They were either genuinely curious about these glowing masses or were poking fun at my passion for all things science.  I am going to assume it was genuine curiosity, and answer their questions below.

Pushing the Boundaries of Science Like Pushing a Vacuum

As far as division of labour around the house goes, my wife and I each have our own respective duties, and one of mine is vacuuming the house.  I kind of enjoy mindless activities like this one, because it allows me to shut off my brain for the better part of thirty minutes.  But with the mind unfocused, it is at once free to wander; I find that I do some of my deepest thinking while under the hypnotic trance of the vacuum's purr.

Once, while seeking out lose dirt and dust-bunnies with my trusty dust-sucker, my mind began to wander even further than normal.  I began to see clear parallels between my search for dust around the house and humanity's pursuit of science in general.  Before I go any further, let me assure you that I realize that only one of these two endeavours is of great importance, and it is not the one that involves me pulling out the couch, cleaning behind it, and pushing it back.

Dust around the house tends to accumulate in the places we encounter the least.  Sections of the home in plain sight are relatively free of such particles, as these areas are well-travelled.  The dust gets displaced to a new spot due to the relative motion of air around it.  If this new spot also sees regular activity, the dust will inevitably move yet again.  It will only settle permanently in a quiet, unused spot within the room (usually behind something heavy, to the vacuumer's chagrin).  The phenomenon is much like snow on a high-traffic ski slope, which tends to build up on the two outer edges.

How then is vacuuming like scientific advancement?  Imagine that each piece of dust to be collected is like a scientific mystery to be solved.  Much like the loose dirt that we wish to suck up, the vast majority of the mysteries associated with the physical world are well-hidden - that is, unless we search for them explicitly, we will not even know that they exist.

Each room within the house may be thought of as a scientific pillar, each with its own particular sort of unsolved mysteries waiting to be uncovered.  We could have physics in the family room, chemistry in the kitchen, biology in the bathroom, and so on.

In the early going of modern science, the house was a complete mess throughout.  As almost no one was taking part in scientific research, dirt was evenly distributed.  When Isaac Newton decided to begin to clean the house, he began with what he interacted with most on a daily basis - that which was the most visible.  In the late seventeenth century, he uncovered the basic principles of mechanics (the motion of bodies) and geometric optics (the behaviour of visible light).

As the study of physics moved along, research in other fields of science began.  Before long, each room in the house was being cleaned in parallel.  The science research landscape was a busy one indeed during the twentieth century. 

As the dust settles, and the twenty-first century soldiers on, we may look at the house and conclude that it is clean.  Scientific principles may be invoked to explain just about everything we typically interact with.  That which was most obvious, that which presented itself, has been sucked up by the scientific research community.  All that remains to be discovered in the present science landscape is that which is not in plain sight.

Ender's Game, The Movie

You know that uncomfortable feeling that you get upon learning that your absolute favourite novel will be spun into a Hollywood film?  I am currently dealing with such a feeling in regard to my favourite sci-fi novel, Ender's Game, which will hit the big screens in the spring of 2013.  On the one hand, I am excited to experience this wonderful story through a new medium, but on the other, I fear that the movie will not live up to the book. 

It is strange for one to have such strong feelings for a story that one takes offense to a lacklustre portrayal of it.  After all, I am not Orson Scott Card, the author of the Ender's Game series of novels, of which Ender's Game was the original publication.  But, that is what is special about a novel: the reader has the freedom to make the story their own, and in so doing, develops a much more intimate relationship with it than can be established through film.

I first read Ender's Game (I have read it twice since) in 1999, as part of a college English class.  The 1985 novel may be summarized as follows: Star Wars meets Harry Potter without the hocus pocus.  The story examines two advanced species, mankind and formics (commonly referred to as "buggers"), for whom this neighbourhood of the universe is not big enough.  The story unfolds almost entirely on a military base in space, where young boys and girls are trained in space war.  Harry Potter fans will draw comparisons between this training facility, known as Battle School, and Hogwarts, but to be fair, J. K. Rowling's fictional world was created after Card's.

The Art of Presenting

As part of my physics courses, my students are usually required to perform a powerpoint presentation about a course-related topic that they find interesting.  As harmless as it sounds, the very idea of speaking in public induces fear in many of my students.  While I do sympathize with them, these presentations remain a part of my courses because (1) oral communication is an important skill, and (2) I feel that if you cannot communicate what you have learned, you have not learned it.

Jerry Seinfeld once observed that the number one fear of most people is public speaking, while number two is death.  He went on to muse that, at a funeral, the majority of people would rather be inside the casket than giving the eulogy. 

What is it about giving a presentation that is so scary?

Engineering Firms Can be a Drag

I had the great privilege of taking in a 45 minute long keynote speech by Canadian astronaut, Dr. Robert Thirsk, at a teacher's workshop last month.  The speech was about inspiring students to pursue the sciences, and also included an inside look at the incredible career that Dr. Thirsk has enjoyed.  To be clear, the overall message was not "Inspire young students in science and math and they will all become astronauts."  While the presentation did include awe-inspiring visuals of Dr. Thirsk floating in low Earth orbit, the take home message was grounded in reality: science is interesting and can lead to a wide spectrum of promising careers.

But, let's be honest.  No engineering career stacks up against what Dr. Thirsk and his handful of colleagues do. Not more than two years ago, the man at the microphone took part in forty unique science experiments over a six month period aboard the International Space Station.  He ate space food and exercised on specialized zero-g cardiovascular machines for two hours per day (to minimize bone density loss).  For every engineer that can boast about a work experience as rich as this, there are literally thousands who spend their days deciding whether to use three bolts or four bolts to connect parts at interfacing flanges.

What, in the first place, draws engineers to pursue a career in engineering?  Usually, possessing strong math skills and having a comfortable understanding of physics can sway a young student towards the direction of engineering.  However, the desire to work on ground-breaking projects - the first lunar mission, the first nuclear reactor - this is what budding engineers envision for themselves.  Engineers want to have a hand in shaping the technological landscape of the future.  The sad reality is that only so many hands have the opportunity to take part in such shaping.