“Stop saying zero gravity” 

While shopping around for a new bed, I discovered that the phrase “Zero gravity” has gone thoroughly mainstream. Apparently, there are “zero g sleeping positions” available now if you are willing to put down a few thousand dollars. 

What numbers among physics students have heard of  “Zero gravity”? Do students think that astronauts on the ISS are floating because of the absence of gravity there? I have anecdotal evidence gathered over the years from student answers to these two questions. I wanted to gather data on this and distributed a survey over social media. Those who responded to the survey include students from a top public high school, a large state flagship university and a private liberal arts college all in the northeast U. S. I am hoping that the results are of interest to all of us, physics educators. 

Here is the abstract of my presentation at the upcoming AAPT Summer 2021 virtual meeting.

The term “zero gravity” first appeared in NASA’s technical bulletins in 1968. Since then “zero g” has become extremely common in popular usage. We also often hear talk of astronauts on the International Space Station (ISS) being weightless or experiencing zero gravity. I present here preliminary results of a survey conducted on social media of college students in the U.S who have taken a physics course in high school or college. Participants were asked about their familiarity with “zero g” or “zero gravity” and also if they thought that astronauts float because of zero gravity. The results show that a very high percentage of students surveyed are aware of the term. Significant numbers among them think that astronauts float due to the absence of gravity, a belief that does not appear to be based on a conceptual understanding of free fall/circular motion and scientific reasoning.

Is it a good idea to use 'The Big Bang Theory' clips to teach physics?

When The Big Bang Theory (TBBT) aired for several years on prime time network television, it was a like a breath of fresh air for me. The show had scientists and engineers as major characters. It also had several physics related plot devices and dialogues. Several female characters on this show were smart, successful scientists. One actress playing a major role was a neuroscientist in real life! So it would seem that the clips of TBBT would be ideal science teaching devices. 

But TBBT had a major flaw in the way it portrayed Sheldon, the character who seemed to exhibit behaviors consistent with Asperger Syndrome. In several episodes, Sheldon is repeatedly shown to be inviting mockery and exasperation from all around him.

Margaret Weitekamp in Physics Today (January 2017, page 40) writes on how BBT reinforces and also plays against stereotypes.

Leaving this problem aside, what of the physics itself seen on the show? Or how accurate is TBBT Physics? Don Lincoln at LiveScience discusses several plotlines of the show that do not ring true from the perspective of a FermiLab physicist. His quibbles have to do with the theory of "Super Asymmetry" as introduced in the show in addition to portraying the scientific endeavors as a two-man set up as opposed to reality of hundreds of scientists collaborating together on projects such LHC.    

I am intrigued by the so called “low brow” Physics interspersed throughout TBBT. How do we use this tool in the classroom and how good is it?

My answer is:  use with caution. Here is an illustration as to how.

I have used the problem below in class along with the video to address a common misconception in kinematics: stopping distance depends on the mass of the moving object.

The problem statement:

While Penny is giving Sheldon a ride in her car, Sheldon complains about how fast she is driving and describes what would happen to them in the event of a crash.

Is Sheldon "wrong" to include Penny’s weight while calculating the stopping distance of her car?

Yes, stopping distance, in theory, depends only on the square of the velocity of the car and the deceleration supplied by the brakes. 

The magnitude of deceleration is simply a product of the coefficient of kinetic friction and acceleration due to gravity. 

So, for a given velocity, the deceleration provided by dry pavement is independent of the mass of the car and its riders.

BUT, in practice, the coefficient of friction is seen to vary with the weight with which the vehicle and driver push down on the road. 

So... coefficient of friction is not really a constant when we talk about HUGE moving masses such as semis and trucks. 

But for Sheldon and Penny, no, their mass is not a factor in stopping. That is the caveat, folks. 

  

 

How did I learn physics in India?

Professor Tom Greenslade  is Millikan Medal winner, a living resource on the history of physics & classic physics laboratory experiments, and prolific author of over 300 research works. So, I was absolutely thrilled to receive a sweet note from him on my meter stick demo paper.

He shared with me the details of how he got started in physics education and I wrote him a long reply on my family background and what it was like learning physics in India. Our emails brought back so many memories and I started thinking about the differences in the way physics is taught in the United States and India.

As it happens, AAPT WM2021 had a whole session dedicated to international perspectives on teaching/learning physics. Not sure it is a new initiative but I cannot think of a better way to expand AAPT’s reach and inform physics educators around the world how their counterparts in other countries teach physics.

Two presentations in WM2021 caught my interest. The first was someone who had their high school and undergraduate physics education in Srilanka. She detailed how high school or college students in their classes in Srilanka are never encouraged to ask questions or to meet their professors outside of class. Students are entirely on their own as far as making sense of the material is concerned. I could relate to most of her presentation having experienced things very similar in India. Just like her, I had to surmount the language barrier - learning all the school subjects in my mother tongue (Tamil)  till Grade 11 and then switching over to learning everything in English .

But left unsaid was how much students depend on TUTORING which happens entirely outside the school or college. Dedicated academic support services run within educational institutions simply do not exist in India or Srilanka or any of the South Asian countries (as far as I know). But there are thousands of privately run ‘coaching classes’, prep courses, YouTube channels and neighborhood tutors for every subject. So, in this sense, students are not entirely ‘independent learners’.

The other presenter gave a somewhat opposite point of view and argued that students learn best when teachers go out of their way. The presenter suggested that the best way to improve learning is for educators to play Mom and Dad and envelope students in tender loving care.

I am, as in many other areas of life, from the Twilight Zone. I did not have access to any kind of physics tutoring in or out of college or high school. My siblings, physics majors no less, tried to tutor me and we ended the torture fifteen minutes into it by mutual agreement. Nor was I lucky to have physics educators who were great at teaching or had the time and energy to care truly about student learning. I have always been an independent learner and the lack of a support structure can be seen in my career trajectory. 

But physics experiences early in life have a way of staying with you. I was raised by my grandparents in a small town in South India. My grandfather’s prized possession was a pan balance with a set of weights (masses, rather) which he used to weigh old newspapers. (In those days, one could sell old paper to recycling collectors and make small sums of money.). Milk vendors would come home and measure out the required amounts in liter and milliliter containers. 

Growing up a girl in patriarchal society meant staying home all day and training how to be a good housewife. That meant lots of time observing my mother in the kitchen. I learnt how to cool hot milk quickly by placing a long metal spoon in it so that the heat could be conducted away. I watched as she placed hot food on a stainless steel plate and left it on the floor. Since the coldest air in a room is denser, it stays close to the floor and placing food in metal container on the floor guarantees faster cooling. I also understood why stew that boils quickly is a huge problem if all the vegetables in it need to cook completely. 

Having no access to a public water distribution line and facing a drought in the area, grandpa had to dig a second well in the front yard. I would overhear well diggers talking about the pipe length needed to pump water out of the well.

Now I realize why torque, static equilibrum, density and heat transfer are my favorite introductory topics to teach!