Friday, November 2, 2012

"Slow Mo Guys" = Great Teaching Tool

"Sir, you're going too fast!" - it is a complaint I hear in my physics classes every so often.  Whether it is the case or not, it is true that there is an ideal speed for progressing through science content in a classroom setting.

Similarly, there is an ideal speed for the viewing of the countless science phenomena that occur in nature.  Often times, events like chemical reactions or travelling waves elapse over too short a time interval to be properly grasped.  This is actually the reason why many scientific phenomena that are now well understood went misunderstood for so long (and why others still go misunderstood).

Take something simple, like an apple falling from a tree.  Five centuries ago, people believed that the fall was at a constant speed, which was governed by the apple's mass (heavy apples would fall faster than light ones).  Of course, this assessment is wrong on many levels, but one can easily appreciate why such a faulty conclusion could be arrived at.  The entire fall of an apple might take one second, which is an insufficient amount of time for a person to gauge an event.

Had mankind invented the video camera a few centuries earlier than it did, enabling it to see the world in slow motion, early science would have evolved more rapidly than it did.  The apple could then be seen to displace more and more with each passing frame, invalidating the constant speed theory.

Some people today may not see how valuable adjusting the frame rate of an event is outside sports and action movies.  Fortunately, a few young people certainly do, and they are responsible for my current favourite YouTube channel: "Slow Mo Guys".

The premise employed by these humourous individuals is fairly simple: record a science phenomenon with exceptional audiovisual equipment, and play it back in super slow motion.  They have a guy getting hit in the face with a soccer ball, and you can actually see the wave caused by the force propagate across his cheeks.  Similar fun is had when popping water balloons (again, on someone's face - there is a theme of pain in the collection of videos).  There is also the classic mentos in diet coke trick.

How slow is slow?  Depending on the event, they are sometimes presented at 1000 frames per second, other times at 10,000 frames per second.  What's more, the resolution of the camera is phenomenal, so that, for example, one can actually see each droplet of water clearly in the fire vs water video.

Below are links to two particular videos that would be of interest to any physics student studying mechanics (the jumping cat) or electricity (the smashed light bulbs).

Double Jumping Cat and Smashing Light Bulbs

It is nice to see that millions of people watch these videos.  They get a dose of science with their entertainment.  When we slow things down, we are forced to take the time to analyze them.  Sometimes, the pace of our lives forces us to bypass the subtle and beautiful aspects of nature.

By the way, if you think that these frame speeds are impressive, you will be floored by the cutting edge in optical technology: video cameras that can capture photonic events.  Ramesh Raskar gave a TED talk of his work at MIT that must be seen to be believed.  His camera can record events at one trillion frames per second.  He shows a light ray as it travels through a medium at a speed that is ten billion times slower than what it is in reality.  The speed of light is thus slowed down for our viewing pleasure, from 300,000,000 m/s to 0.03 m/s (3 cm/s).

Of course, some of nature's phenomena take months to occur.  In such cases, like that of a blooming flower, it is nice to have the event recorded over days or weeks, and to play it out over the course of seconds.

I suppose that part of my role as a teacher is to adjust the frame rate of my course so as to be neither too slow nor too fast.  Thanks to technological advances in imaging, we can ask nature to do the same.

No comments: