Sunday, September 21, 2014

Antimatter Explained

Another short and sweet video from MinutePhysics, this time it is the explanation on what antimatter is.



However, I think the explanation given earlier on the same subject is a bit more in-depth and less "manic" than this one.

Zz.

Tuesday, September 16, 2014

"What keeps girls from studying physics and STEM" - An Important Article That Did Not Answer Its Own Question

Anyone following this blog for any considerable period of time would have seen my keen involvement in trying to engage more girls and women into physics. So this is a subject that I've followed and had participated in for many years.

So when I came across this opinion piece article, I will read it in its entirety, because even if this is a first-hand account of one's experience (the author is a female physicist), it is still another "data point" in trying to figure out what kind of hurdle a female student like her faced during her academic years.

Unfortunately, after reading the article, I am no closer in understanding the unique challenges that a female student faces, or what a female scientist faces, in the field of physics. She describes what can be done to improve education and open opportunities, but these are NOT specific to female students!

My advanced placement (AP) physics class, unfortunately, was about memorizing equations and applying them to specific contrived examples. I did not perform well on the midterm exam. The teacher advised me to drop the course, along with all the other girls in the class. 

This would be a turn-off for male students as well! So if that is the case, why is there an overwhelmingly more female students leaving the subject? She didn't say.

I stayed despite the teacher’s pressure, as the only girl in the class, and did well in the long run. I learned to love physics again in college, conducting original research with inspiring science professors who valued my presence in the scientific community. Physics professor Mary James at Reed College helped a lot by creating an active learning environment in her courses and teaching me that physics also needs “B” students.

Again, any student of any gender would benefit from that. This is not unique only to female students. So it still does not address the imbalance.

But there is so much more work to do. One key factor is federal funding for research. Federal funding is the main source of support for the kind of high-risk, high-reward investigations that sparked innovations such as the Internet, the MRI and GPS.

U.S. Sen. Patty Murray, D-Wash., serves on the U.S. Senate Appropriations Committee and understands the connection. In her recently released report “Opportunity Outlook: A Path For Tackling All Our Deficits Responsibly” she states, “By supporting early stage basic research that the private sector might not otherwise undertake, federal investment in R&D [research and development] has played a critical role in encouraging innovation across a swath of industries.” 

Again, this doesn't address the lack of women in physics. Increasing the opportunity and funding merely increase the overall number of people in the field, but will probably not change the percentage of women in this area. There's nothing here that reveals the unique and unforeseen hurdles  that only women faced that are keeping the participation down.

In the end, she simply argued for more funding to increase the opportunity of people in physics. There's nothing here whatsoever that addresses the issue of why there are very few women, both in absolute numbers and in relative percentage, in physics. I think there are other, better articles and research that have addressed this issue.

Zz.

Saturday, September 13, 2014

When Stephen Hawking Burps, The World Media Goes Crazy!

Yes, I categorize this as a burp, which reveals how uninteresting and how little importance I put on this piece of news that has somehow garnered such widespread attention.

Whenever the name Stephen Hawking and the phrase "destruction of our universe" appear on the same sentence, that is just an incendiary combination that usually caused a world-wide explosion (pun intended). That's what happened when Hawking said that the Higgs boson that was discovered a couple of years ago at the LHC will result in the destruction of our universe.

My first reaction when I read this was: YAWN!

But of course, the public, and the popular media, ran away with it. After all, what more eye-catching headline can one make beyond something like "Higgs boson destroys the universe - Hawking". However, I think those strangelets in the LHC collisions that were going to form micro blackholes that will swallow our universe were here first, and they demand that they'd be the first to destroy our universe.

There is an opinion piece on the CNN webpage that addressed this issue. When CNN had to invite someone to write an opinion piece of a physics news, you know that it had gotten way too much attention!

So, the simplified argument goes like something like this -- the Higgs particle pervades space roughly uniformly, with a relatively high mass -- about 126 times that of the proton (a basic building block of atoms). Theoretical physicists noted even before the Higgs discovery that its relatively high mass would mean lower energy states exist. Just as gravity makes a ball roll downhill, to the lowest point, so the universe (or any system) tends toward its lowest energy state. If the present universe could one day transition to that lower energy state, then it is unstable now and the transition to a new state would destroy all the particles that exist today.

This would happen spontaneously at one point in space and time and then expand throughout the universe at the speed of light. There would be no warning, because the fastest a warning signal could travel is also at the speed of light, so the disaster and the warning would arrive at the same time.

That was the pedestrian description of what Hawking is talking about. But don't just stop there or you'll miss the CONTEXT of the probability of this happening.
 
Back to the universe. Whether the existence of Higgs boson means we're doomed depends on the mass of another fundamental particle, the top quark. It's the combination of the Higgs and top quark masses that determine whether our universe is stable.

Experiments like those at the Large Hadron Collider allow us to measure these masses. But you don't need to hold your breath waiting for the answer. The good news is that such an event is very unlikely and should not occur until the universe is many times its present age.
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So don't lose any sleep over possible danger from the Higgs boson, even if the most famous physicist in the world likes to speculate about it. You're far more likely to be hit by lightning than taken out by the Higgs boson.

 See what I mean when I said that I yawned when I first read about Hawking's speculation?

Zz.

Friday, September 12, 2014

The New Physical Review Journals Website - It Sucks!

Yeah, so from the title, you can already tell how I feel about it.

I look at the Physical Review Journals webpage quite often, at least a few times a week. After all, PRL is a journal that I scan pretty often, and I'm sure most physicists do as well. They changed the look and feel of the webpage several months ago, and right off the bat, there were a few annoying things.

First of all, one used to be able to see immediately the current list new papers appearing that week (for PRL, for example). Now, you need to click a few links to find it.

The page is heavily emphasized on "highlighted" papers, as if they are desperately trying to push to everyone how important these are. I don't mind reading them, but I'd like to see the entire listing of papers that week first and foremost. This somehow has been pushed back.

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Lastly, and this is what is annoying the most, they seemed to not be optimized for tablet viewing, at least, not for me. I often read these journals on my iPad. I have iPad3, and I use the Safari browser that came with it. Had no problem with the old webpage, and other journals' webpages. But the new Phys. Rev. webpage is downright annoying! Part of the table of content "floats" with the page as one is scrolling down! I've uploaded a video of what I'm seeing so that you can see it for yourself.

I've e-mailed my complaints to the Feedback link. I had given it a few months in case this was a glitch or if they were still trying to sort out the kinks. But this seems to have persisted. I can't believe I'm the only one having this problem.

It is too bad. They had a nice, simple design before, and I could find things very quickly. Now, in trying to make it more sophisticated and more slick, they've ruined the usability for us who care more about getting the information than the bells and whistles.

Zz.

Wednesday, September 10, 2014

"Interactions between teaching assistants and students boost engagement in physics labs"

I will say that, having read this paper rather quickly, I am not surprised by the conclusion, and neither should you. The paper is available for free at the link given above.

Abstract: Through in-class observations of teaching assistants (TAs) and students in the lab sections of a large introductory physics course, we study which TA behaviors can be used to predict student engagement and, in turn, how this engagement relates to learning. For the TAs, we record data to determine how they adhere to and deliver the lesson plan and how they interact with students during the lab. For the students, we use observations to record the level of student engagement and pretests and post-tests of lab skills to measure learning. We find that the frequency of TA–student interactions, especially those initiated by the TAs, is a positive and significant predictor of student engagement. Interestingly, the length of interactions is not significantly correlated with student engagement. In addition, we find that student engagement was a better predictor of post-test performance than pretest scores. These results shed light on the manner in which students learn how to conduct inquiry and suggest that, by proactively engaging students, TAs may have a positive effect on student engagement, and therefore learning, in the lab.

When I was a lab TA way back when, I tried to engage the students while they were performing the experiments. I tried to ask them on-the-spot questions, such as why do we need to measure the time for the pendulum to make 20 oscillations when all we care about is the time for one oscillation (period). I ask them many things about why they think we do this and that, rather than a seemingly-simpler and more direct measurements. I also ask them stuff related to the physics, such as during an experiment that used springs, what they think would be different if we were to do the same experiments on the moon instead.

Obviously, I couldn't do a study like these people did and investigate if what I was doing had any effects on the students and their lessons. However, I did get a lot of positive feedback from the course review. This new study reinforces the vital role that Lab TAs could play, and they need to read this paper to realize that they might have a non-trivial influence on the students.

Zz.

The Physics of Wireless Charging

Rhett Allain has another informative article on how wireless charging of electronic devices work. This technology will be more prevalent in the near future as everyone is getting fed up with searching for power cords to charge their cell phones, tablets, etc.

Zz.

Friday, September 05, 2014

Particle Physics In A Superconductor

It has finally come full circle.

The Higgs mechanism, which came out of the phenomenon of superconductivity and were then used in elementary particle physics, has come back to superconductivity with the latest result published in Science. In this report, physicists see the similar Higgs boson signature in superconductors as those described in particle physics.

To find it in a superconductor in its normal state, Shimano and colleagues violently shook the superconductor with a very brief pulse of light. Shimano says it is similar to how particle physicists create the real Higgs boson with energetic particle collisions. They first created the superconducting Higgs last year, and have now studied its properties to show that, mathematically speaking, it behaves almost exactly like the particle physics Higgs.

Again, this is similar to the discovery of magnetic monopole in spin-glass system and the discovery of Majorana fermions. A lot of particle physics can be done in condensed matter!

Thursday, September 04, 2014

Scientific Consensus

A very good article on what "scientific consensus" is and what it actually means on Ars Technica. This is in light of the attack on scientific consensus related to global warming.

In an earlier discussion of science's standards for statistical significance, we wrote, "Nobody's ever found a stone tablet etched with a value for scientific certainty." Different fields use different values of what they think constitutes significance. In biology, where "facts" are usually built from a large collection of consistent findings, scientists are willing to accept findings that are only two standard deviations away from random noise as evidence. In physics, where particles either exist or don't, five standard deviations are required.

While that makes the standards of evidence sound completely rational, they're also deeply empirical. Physicists found that signals that were three standard deviations from the expected value came and went all the time, which is why they increased their standard. Biologists haven't had such problems, but other problems have popped up as new technology enabled them to do tests that covered tens of thousands of genes instead of only a handful. Suddenly, spurious results were cropping up at a staggering pace. For these experiments, biologists agreed to a different standard of evidence.

People who don't know any better tend to lump things into simple terms, as if such a thing can be done. I've always said that in science, there is such a thing as a degree of certainty, that in some areas, the certainty is stronger than in others. The same can be said about the level what we accept something as valid evidence, or at least, valid enough. The article accurately describes why in one part of science, a loser level is sufficient, while in another part of science, a stricter level is needed. These are all based on experience and based on what has happened before, but to be able to do that, one MUST be well-experienced in what is going on in that particular field!

What it comes down to is that people who are experts in certain fields tend to have a "feel" on when something becomes convincing, or at the very least, there is a serious consideration on the validity of something. This is hard to do when you are an outsider. It is not because it is a closed society. Rather, it is just that one needs to have a long set of knowledge and experience in the field to know when something is valid.

This is an article that laymen, and especially politicians, should read.

Zz.

Wednesday, September 03, 2014

Myth Physics: Gravity Is Much Weaker Than Electromagnetism

In this article, Vic Stenger tries to debunk the "myth" that gravity is much weaker than electromagnetisim.

I don't see this as a myth, but rather, an explanation on what we mean when we say that gravity is weaker than EM. Stenger explains it here:

The gravitational force between two particles is given by Newton's law of gravity, which says that the force between two point masses is proportional to the product of the masses and inversely proportional to the square of the distance between them.

The electric and gravitational force laws are both inverse square laws, so if one computes the ratio of the forces between two bodies, the distances cancel. For the electron and proton, the gravitational force is 39 orders of magnitude weaker than the electrical force. This is the source of the myth that gravity is a much weaker force than electromagnetism.
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The absolute strength of the electromagnetic force is specified by a dimensionless parameter alpha called, for historical reasons, the fine structure constant. It is actually not a constant but varies with energy. However that variation is very gradual and for most practical purposes alpha can be taken to have a value of 1/137

Conventionally a dimensionless parameter alpha-G is defined to represent the gravitational force strength. It is proportional to the square of the proton mass and has a value 23 orders of magnitude less than alpha. So "officially," gravity is this much weaker than electromagnetism.

So there you have it. This is another lesson on why one must understand a bit of the physics behind the phrases and expressions that we all often hear out of science. You cannot just take something at face value, the way pseudoscientists such as Deepak Chopra often do all the time.

Zz.

The Physics of Proton Therapy

If you have read the news, you would have heard of the issues surrounding the parents of a sick child desperately seeking to have their son undergo a proton therapy.

Jon Butterworth has a nice article for the general public on the physics of proton therapy, and especially why it is different than other forms. When you are reading this, please note that this medical treatment came DIRECTLY out of our knowledge of experimental high energy physics, y'know, the physics that many people could not see the use of. So next time when someone questions the applications and benefits of funding this area, you point to him/her this article!

Zz.

Feynman Lectures

This news was posted only yesterday, regarding the availability of Feynman Lectures online for free. However, if you have followed this blog, I announced this availability almost a year ago! Mike Gottlieb announced this on Physics Forums way back then when he started the project. I posted the latest update on the project from him also on this blog.

So there, you are ahead of the curve! :)

Zz.

Wednesday, August 20, 2014

How Long Can You Balance A Pencil

Minute Physics took up a topic that I had discussed previously. It is about the time scale on how long a pencil can be balanced on its tip.



Note that in a previous post, I had pointed out several papers that debunked the fallacy of using quantum mechanics and the HUP to arrive at such time scale. So it seems that this particular topic, like many others, keeps coming back every so often.

Zz.

Friday, August 15, 2014

Cuddly Plushes At Synchrotron Beamlines

I mentioned of my final visit to the NSLS before its impending shutdown. I had to stop and chuckle at one of the UV beamlines during my casual tour around the place. There were cuddly plushes strategically placed along the beamlines, including Kermit and Miss Piggy in a rather amorous position (not that there's anything wrong with it).

And yes, I took a few photos.


I hope they remember to rescue these guys before the wrecking ball arrives.

Zz.

Thursday, August 14, 2014

Saying Goodbye To NSLS

I had a chance recently to visit my old romping ground, the National Synchrotron Light Source (NSLS) at Brookhaven Lab. I spent 3 years there doing my postdoc work, and the facility is about to be shut down at the end of Sept. 2014 as the new facility, the NSLS II just right next door, will take over. The old lady is still running, but you can tell that she's old, decrepit, with lots of aches and pains, and about ready to retire. One can tell that this place is about ready to be shut down when even the vendors no longer refill the vending machines!

I was there on the day that Long Island, NY received 13 inches of rain within a 12 hour period, and walking in the next day, I saw leaks and a few water issues. Oh yeah, the old lady is definitely ready to go. The NSLS was such a workhorse during her glory years. To say that she was over-subscribed is an understatement. The place was packed with users on top of each other. The presence of two separate rings, one for the x-ray and the other for the UV/IR/low energy photons, made it quite unique and useful for many applications and studies.

Across the street from her is the new lady on the block, the NSLS II. She's huge when compared to the old lady, she's shiny and new, more powerful and sleeker. I look forward to visiting her when she's in operation, but I'll never forget the one I spent a lot of days and nights with. She gave me good data. How many dates have you been on where you can say that?

So long, NSLS!

Zz.