Tuesday, August 14, 2018

MinutePhysics Special Relativity Chapter 8

If you missed Chapter 7 of this series, check it out here.

This time, the topic is on the ever-popular Twin Paradox (which really isn't a paradox since there is a logical explanation for it).

You can compare this explanation with that given by Don Lincoln a while back. I think Don's video is clearer to me, since I can comprehend the math.


Thursday, August 09, 2018

Is Online Education Just As Good And Effective?

Rhett Allain is tackling a topic that I've been dealing with for a while. It isn't about learning things online, but rather is an online education and degree just as good and effective as brick-and-mortar education? Here, he approached this from the point of view that an "education" involves more than just the subject matter. It involves human and social interaction, and learning about things that are not related to your area. He used the analogy of chocolate chips and chocolate chip cookies:

The cookie is the on-campus experience. College is not just about the chocolate chips. It's about all of that stuff that holds the chips together. College is more than a collection of classes. It's the experience of living away from home. It's the cookie dough of relationships with other humans and even faculty. College can be about clubs and other student groups. It's about studying with your peers. College is the whole cookie.
But wait! While we are talking about learning stuff, I have one more point to make. Don't think that you should acquire all of the skills and knowledge you need for your whole career during your time at school. You will always be learning new things, and there will always be new stuff to learn (no one learned about smartphones in the '80s). In fact, a college degree is not about job training. It's not. Really, it's not about that.

Then what is the whole chocolate chip cookie about? It's about exploring who you are and learning things that might not directly relate to a particular field. College is about taking classes that might not have anything to do with work. Art history is a great class—even if you aren't going to work in a museum. Algebra should be taken by all students—even though you probably won't need it (most humans get by just fine without a solid math background). So really, the whole cookie is about becoming more mature as a human. It's about leveling up in the human race—and that is something that is difficult to do online (but surely not impossible).

I have no issue with these points. However, we can even go right down to the jugular with this one instead of invoking some esoteric plea for a well-rounded education and social skills. There are compelling evidence that online-only lessons are not as effective and efficient as in-person, in-class lessons, if the latter is done properly.

I will use the example of the effectiveness of peer-instruction method as introduced by Harvard's Eric Mazur. Here, he showed how active learning, instead of passive learning, can be significantly more effective for the students. In such cases, student-to-student interactions are a vital part of learning, with the instructor serving as a "guidance counselor".

This is not the only example where active learning is more favorable than passive learning. There have been other students that have show significant improvement in students' understanding and grasp of the material when they are actively engaged in the learning process. Active learning is something that hasn't been done and maybe can't be easily done with online lessons, and certainly not from simply watching or reading the material online.

So forget about honing your social skills or learning about art history. Even the subject matter that you wish to understand may be more difficult to comprehend when you do this by yourself in an online course. There are enough evidence to support this, and it is why you shouldn't be surprised if you struggle to understand the material that you are trying to learn by yourself.


Wednesday, August 08, 2018

Loop Quantum Gravity

This is one of those still-unverified theory that tries to reconcile quantum mechanics with General Relativity. I'm not in this field, so I have no expertise in it. But I know that for many people who have read about it, they are aware of String theory and it's competition, Loop Quantum Gravity.

In this video, Fermilab's Don Lincoln tries to explain LQG to the masses.

Keep in mind that this idea is still lacking in experimental support. The gamma ray burst observation that he mentioned in the video has been highlighted here quite a while back.

Without experimental verification, both String theory and LQG continue to have issues with their credibility as a science.


Tuesday, August 07, 2018

Ban Cellphone Use In Classrooms?

First of all, let me state my policy on the use of electronic devices (mobile phones, tablets, laptop computers, etc.) in my classrooms. I do not have an outright ban (other than during exams and quizzes) during class, but they can't be use in an intrusive manner that disrupts the running of the class. So no making phone calls, etc. So far, I haven't had any issues to change that policy. Many of my colleagues do have an outright ban on the use of these devices during class.

Now, a few weeks ago, I came across this paper. They studied students who used these devices for non-class related purposes during class. They found that the distraction of these devices, in the end, affects the average class grade that the student received at the end of the course (they were psychology courses). The distracted students, on average, scored half a grade lower than those that are in classes that ban the use of these devices for non-class related purposes.

But what is also surprising is that there was a collateral damage done onto students who were in the same class as these distracted students, but they themselves did not use these devices during class.

Furthermore, when the use of electronic devices was allowed in class, performance on the unit exams and final exams was poorer for students who did not use electronic devices during the class as well as for the students who did use an electronic device. This is the first-ever finding in an actual classroom of the social effect of classroom distraction on subsequent exam performance. The effect of classroom distraction on  exam performance confirms the laboratory finding of the social effect of distraction (Sana et al.,2013). 
 So this is like second-hand smoking.

The good thing about this is that, I can now tell my students that, while I allow their use in the class during lessons, there is evidence that if they choose to use them, their grades may suffer. I may even upload this paper to the Learning Management System. However, because of the collateral damage that might be done to other students who do not use these devices during class, I am seriously rethinking my policy, and am considering imposing an outright ban on the non-class related use of these devices during my lessons.

If you teach, what is your experience with this?


Sunday, August 05, 2018

APS's Don't Drink And Derive T-Shirt

I was cleaning my closet (I do that now and then) and came across this old shirt from way back when. This was bought during the 1999 APS March Meeting in Atlanta, GA, which celebrated the 100th anniversary of the APS.

When I first saw it, I said to the person at the counter that all the formulae are wrong. And then, duh, it suddenly hit me why and I got it. So of course, I had to buy it.

I haven't worn it in ages, because of a small tear on the front. But I'll probably start wearing it around the house, especially if I'm working on the yard.

This t-shirt is the opposite of the one I bought while I was at the Kennedy Space Center in Cape Canaveral, FL. That t-shirt had all the correct formulae and shows my nerdy self whenever I wear it.



Sunday, July 29, 2018

Looking for Psychics To Teach Physics

I know, I know, this is trivial, but it is so hysterically funny!

Someone pointed this out to me and I couldn't stop giggling. So of course I have to share it with all of you! This is a jobs ad from Kennedy-King College, one of the City Colleges of Chicago. They are looking for someone to be an adjunct physics faculty member to, presumably, teach physics.

I'm doing a screen capture here, because I expect someone there will see this and make corrections to it soon... or maybe not!

I am guessing that two different people did this, because the category for the job is correct (circled in green), and the required qualification is also spelled correctly, but then it goes hysterically wrong in the job description. It says:


Kennedy-King College is currently seeking a part-time Faculty to teach Psychics during the Fall  2018 semester. 

Well of course they're looking for Psychics. This is because they want a part-time Faculty to teach it during this upcoming Fall semester!

Dear Kennedy-King College, you may want to have someone proof-read your ad. The spell-check would not have flagged you for this hilarious error. And for an academic institution, this is an embarrassing boo-boo. Having psychics to teach physics is like having heretics coming in to teach Sunday School.


Friday, July 27, 2018

Gravitational Red Shift Shows That Einstein Is Right Once More!

Albert Einstein's General Relativity is 3-for-3 this year so far! We already had GR passing its first galactic-scale test, and then we had the verification of the strong equivalence principle. This time, observation of light from a star in our Milky Way passing near a supermassive black hole has shown the predicted gravitational red shift. Holy Cow, Batman!

The team compared the position and velocity measurements from GRAVITY and SINFONI respectively, along with previous observations of S2 using other instruments, with the predictions of Newtonian gravity, general relativity and other theories of gravity. The new results are inconsistent with Newtonian predictions and in excellent agreement with the predictions of general relativity.
The new measurements clearly reveal an effect called gravitational redshift. Light from the star is stretched to longer wavelengths by the very strong gravitational field of the black hole. And the change in the wavelength of light from S2 agrees precisely with that predicted by Einstein’s theory of general relativity. This is the first time that this deviation from the predictions of the simpler Newtonian theory of gravity has been observed in the motion of a star around a supermassive black hole.

A copy of the paper (or maybe a preprint) can be found here.

It bears repeating: the more they test it, the more convincing it becomes!


Thursday, July 26, 2018

The Physics Of Baking Pizza

For those who are purist and prefer the thin-crust, Neopolitano-style pizza, this one might be right up your alley.

This preprint on ArXiv tackles the question on whether baking such pizza is better done in a stone over rather than the standard metal ovens. Which one do you think will win?

Stone ovens heat up to very high temperatures, higher than typical home ovens. But ceramic or stone surface also has low thermal conductivity while having a high specific heat. It means that it retains heat longer and does not cause the dough to burn. It is why this is also the preferred way to bake rustic, crusty bread.

I guess we all just have to build a brick pizza oven in our backyards! :)


Saturday, July 21, 2018

University Research Made Your Smartphone

A lot of people are ignorant of the fact that a smartphone, or any device, for that matter, is a result of research work done by many people and organization and over a very long time. The iPhone was not solely the work of Apple. Apple benefited from all the scientific and technological progress and accumulation of knowledge to be able to produce such a device. These knowledge and progress are often done many years ago by researchers who work on a particular topic that eventually found an application in a smartphone.

I found this interesting website that highlights how research that originated out of universities under various funding agencies, resulted in the smartphone that we currently have. It lists one aspect of each of the major component of a smartphone that had it initial incubation in university research. A lot of these research work is physics-related. It is why I continue to say that physics isn't just the LHC or the Higgs or the blackhole. It is also your MRI, your iPhone, your GPS, etc...

If you need more background info on this, check out this page.


Friday, July 20, 2018

Feynman's Lost Lecture

If you didn't buy the book or didn't read about it, here's a take on Feynman's Lost Lecture, presented by a guest on Minute Physics video.


Burton Richter Dies at 87

Another giant in our field, especially in elementary  particle physics, has passed away. Burton Richter, Nobel Laureate in physics, died on July 18, 2018.

Richter’s Nobel Prize-winning discovery of the J/psi subatomic particle, shared with MIT’s Samuel Ting, confirmed the existence of the charm quark. That discovery upended existing theories and forced a recalibration in theoretical physics that reverberated for years. It became known as the “November Revolution.” One Nobel committee member at the time described it as “the greatest discovery ever in the field of elementary particles.”

He would be shortchanged if all the public ever remembers him is for his Nobel Prize discovery, because he did a whole lot more in his lifetime.


Thursday, July 19, 2018

MinutePhysics Special Relativity Chapter 7

If you missed Chapter 6 of this series, check it out here.

In this chapter, the concept of spacetime intervals is presented. This is where we have "proper time" and "proper length".