Spaghetti Science

Ever run out of soup noodles and relied on breaking up spaghetti into small 1 to 2 cm pieces? That’s what I just did, and I never realized how many 1-2 mm fragments are generated with each and every break. In fact some bits were even smaller than a millimeter. I realized it by fluke because I was breaking the spaghetti with my hands inside a strainer, and the “dust” trickled through the sieve’s 3 mm holes, decorating the counter top. Here’s what it looked like.

It turns out that this has been common knowledge. Scientists have looked into it as well. According to a Smithsonian article,

To break it requires bending it into a bow shape. Eventually the force of the bend snaps the rod in the middle where it is most curved. But the physics doesn’t end there. That break releases energy back down the pieces of spaghetti in a “snap-back” wave or vibration. There’s enough energy in those waves to break off smaller lengths of pasta.

Jason Daley August 16, 2018

If you first twist the spaghetti, apparently, the “twist wave” travels faster than the snap, dissipating its energy. And the spaghetti breaks cleanly. But it would have taken a lot of impractical twisting in my case, given that I broke each strand several times while clumping several strands together to break them faster.

What goes on when spaghetti cooks? The chemistry part.

There are basically two parts to the process occurring between 55 and 85 oC. Water moves into the starch granules, causing them to expand. But for the pasta to fully cook, its protein has to react. If you have egg noodles, an insoluble network of egg and flour proteins form, trapping the swelling starch granules. A pH of 6, according to molecular gastronomist, Herve This, helps the proteins bind the starch even more firmly. One year I had my students test this notion by acidifying the boiling water with a tablespoon of lemon juice. Surely, enough it prevented the pasta from becoming sticky.

What if you have regular noodles? The same thing happens to the starch. But heat converts the flour’s globular proteins into relaxed chains. If overcooked the chains don’t trap the expanding starch, and its amylopectin diffuses out. As it clings to the surface of different strands, it binds them together. You end up with messy lumps of spaghetti.

Oddly, it never takes me the 10 minutes of recommended cooking time. Five seem to be sufficient to create a slightly al dente spaghetti. What’s also noteworthy is how the same recipe but different shapes of pasta creates a different taste, probably because of the role that texture plays in taste and because different shapes have different surface to volume ratios. Thus varying amounts of sauce cling to each noodle.

Recent research (2021) at the University of Parma in Italy confirmed that pasta is a medium to low-GI food, (glycemic index = GI). That’s related to the fact that the starch granules remain trapped in the network, and so they are not completely hydrolyzed in the small intestine. The GI was lowest for those pastas that were enriched with legumes or other plant based products.

Sources:

Herve This. Molecular Gastronomy. Columbia University Press. 2006

Exploratorium. Soaking Pasta. https://www.exploratorium.edu/food/soaking-pasta

Jason Daley. Physics Reveals How to Break Spaghetti Cleanly In Two. Smithsonian. 16/08/2016

Giuseppe Di Pede and al. Glycemic Index Values of Pasta Products: An Overview. Foods 202110(11), 2541; https://doi.org/10.3390/foods10112541

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Why Don’t the Nucleus’ Protons Repel?

Don’t you wish students asked that question when learning about the atom? Most know that like-charges repel, so why aren’t they troubled by the idea of an extremely small nucleus holding tightly packed positively charged and neutral particles? (An equally important question is: why aren’t quarks and gluons part of the high school curriculum when the concepts have been established for half a century!)


In my final year of teaching, one student (Paul) thought it was neutrons that held protons together. That’s kind of true but how?


The repulsive force is stronger than we imagine at distances like the 3.8 × 10-15 meters between the pair of protons in a helium nucleus. The force is  9 × 109 Nm2/C2 ( 1.6 × 10-19C)2/(3.8 ×10-15m)2 = 16 N or about 3.5 pounds for a single atom!  So if you imagine trying to bond two magnets while aligning the North pole of 1 magnet with the North of the other, you need the equivalent of a “Velcro” between the the two bar magnets. Beyond a very short distance, the Velcro would not help bind the magnets, but when the magnets are close enough, the Velcro’s little loops and hooks could overcome the repulsive force of two like-poles. The force required to hold protons and neutrons together has to be something stronger than electrostatics, and this strong force has to be acting only over short distances.

The strong force has a dual role. It binds the inner parts of a proton , and it also holds separate protons and neutrons together.

(1) For starters, we need to reveal the inner guts of a proton and those of a neutron. Each neutron and proton consists of 3 quarks. The proton has two up quarks, each with a charge of +2/3, and one down quark of charge -1/3 for a sum-charge of +1. The recipe for the neutron is the reverse: two down quarks one up quark for a sum-charge of 0. But what’s more important in keeping them together is another property of quarks called color (unrelated to the everyday sense of the word). In any nucleon (proton or neutron) each quark must be of a different color (red, blue and green).


The real Velcro is in the form of gluons emitted by each quark. These change the color-properties of quarks without affecting their charge. Equally important is that they keep the overall color balance within each quark. This is made possible by the fact that a gluon carries both a color and an anti-color, designated by a bar above the letter of the color. The exchange is what keeps the quarks bound together in each neutron and proton. 

HOW QUARKS REMAIN BOUND TO EACH OTHER IN A NUCLEON (Example: in a proton) When a “red” up quark emits a gluon with anti-green and red, that gluon is absorbed by a green up quark in the proton. Anti-green and green cancel, leaving us with a red up quark. That green up quark’s release of a green-antiblue gluon in turn changes a blue down quark into a green one.

(2) But that in itself doesn’t explain why a proton would overcome the repulsive Coulombic force. So what is it that prevents the protons of an atomic nucleus from flying apart? Within a proton, an up quark can release a gluon which becomes a down quark and an anti-down quark. The down quark replaces the up quark in the proton converting it into a neutron. Meanwhile a neutron will do something similar, but the gluon that the neutron releases (and whose up quark converts it into a proton) turns into an  up quark and an anti-up quark. The anti- up quark will annihilate the up quark from the proton and give back a gluon. At the same time, the proton-emitted gluon’s anti-down quark annihilates a down quark from the neutron to give back the other gluon. And then the whole cycle begins again. If particles are busy bartering they can’t be apart. It’s shown in the film https://www.youtube.com/watch?v=FoR3hq5b5yE, but it became clearer (at least in my mind) when I summarized it with this diagram: 

HOW NUCLEONS ARE ATTRACTED THROUGH THE STRONG FORCE (EXAMPLE PROTON and NEUTRON)

Science Outreach: Two Ends of the Spectrum

CokeMost readers are familiar with the term greenwashing in which certain companies use the jargon from the environmental movement on their label to boost sales. But meanwhile, with regards to packaging and/or manufacturing, they do not implement the ecological practices required to significantly cut waste and pollution.

The worst form of science outreach is actually science-washing. Science-washers make it seem like their sole objective is to enlighten people about the science surrounding an issue. But in reality they are more concerned with self-interest and/or some economic or political objective.  The world of science media is filled with little fires, issues that seem potentially threatening.  In some cases, science can tell immediately if they are staged. But science cannot always tell which of the real fires will die out by themselves and which ones will grow to be devastating. But the science-washer will act 100% certain when some inner belief or vested interest is threatened.

I have notes regarding a 7-year old Montreal Gazette newspaper article about the endocrine disruptor, bisphenol A (BPA). It started with the line, “Relax – food chemicals can’t hurt you.” That was one heck of a general assertion! Did the author, who is a well-known educator and media personality to this day,  forget things like the botulinum toxin, a chemical that can show up in food that hasn’t been preserved properly. Of course incidences of botulism are rare, but the compounds glucose, sucrose, sodium chloride and sodium nitrite are common additives and are far from being innocuous.

There are enough people out there who hate nuances. They will tolerate details as long as there is a clear-cut answer at the end of a short article. The author of The Gazette article did not disappoint. He totally dismissed the concerns about the particular endocrine disruptor. Unfortunately, he failed to mention that there were other compounds in its class, some far more powerful, and that even at that, he failed to look at the problem ecologically where, for example,  extremely low doses had effects on fish.  With endocrine disruptors, it’s not a question of “the dose makes the poison” since they are not acting as poisons but as hormone mimics, and the hormones in question, unlike most poisons, normally operate at very low concentrations. For example, endogenous estrogens and estrogenic drugs operate in the picomolar range ( 10-12 moles per liter) The Centers for Disease Control and Prevention website currently(2020) states:

Human health effects from BPA at low environmental exposures are unknown. BPA has been shown to affect the reproductive systems of laboratory animals. More research is needed to understand the human health effects of exposure to BPA.

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Ed Elmos and the real Jaime Escalante in Stand and Deliver

My criticism of his article was online. How he quickly found out about it was a mystery to me at the time, but the important thing is what he whined about. He said that the details I provided, although accurate, would have confused the public. Here was an educator forgetting the famous line from  Stand and Deliver based on a real-life outstanding teacher, Jaime Escalante who said, “Students will rise to the level of your expectations.”

I wish that article was an isolated incident. There are many people with academic credentials online who blur the line between science outreach and just straight-out public relations. For example, defenders of the health and ecological safety of glyphosate or Enlist Duo’s (glyphosate + 2,4-D and other additives), never get into the nuances. Try arguing with them. When they realize that you are not a communist, anti-vax, anti-science or even an activist, they will try persuade you with bizarre conspiracy theories that smear reputable journalists and the International Agency for Research on Cancer (IARC).

So what does excellent science outreach look like? It looks like the Youtube series Sixty Symbols from the University of Nottingham.  These guys are the real McCoy. Why?  They are not trying to sell you nuclear power or a bigger particle accelerator or the misconception that science is the only way of acquiring knowledge. They are genuinely teaching you one way of looking at the world, and it’s obvious that they have put a lot of effort to step away from their research or other activities to make their knowledge more accessible. In one video by Phil Moriarty, I saw a completely original way of teaching the uncertainty principle.

Uncertainty

An extended musical note versus a short one. The frequency range of the latter is wider. This is related to the uncertainty principle.

It is counter-intuitive but true that a short musical note (like the one created when you chug an electric guitar string to stop it from vibrating) has a wide frequency range. In contrast, if you whistle the same note for an extended period of time, there is just one frequency. Frequency and time are inversely proportional. The momentum of an atomic sized particle, which has significant wave properties, is a kind of spatial frequency. If the wavelength is short, like that of the abrupt musical note, there are a number of possibilities for momentum. If the wavelength is longer, the momentum is known with more certainty, but the particle’s exact location becomes much harder to pin down. It’s stretched like the extended whistle.

When the Nottingham physicists are asked about how well-prepared students are for university physics, they don’t get into a whining session. Given that they are genuinely committed to student-learning, they give constructive criticism. They point out that the topics covered by A-Levels physics teachers (in England) are adequate, but that the math courses are a bit broad in scope and exam-centered with not enough rigorous calculus. It is an important point that, if addressed, will help students as much as it will help professors. In contrast, those who do poor outreach rarely give useful tips. One particular individual, who went on to work for the front group ACSH, once criticized an article revealing that lots of science Nobelists are alumni of public high schools. Why? He worried about the bad impression it would make on private schools.

Authentic and quality outreachers are not afraid to show the human face of science. In Falsifiability and Messy Science, another Sixty Symbol video, ( maybe go for a coffee during the Master Class advertisement by Neil Tyson!) Phil Moriarty argues that there is no clear-cut definition of science. Different teams have different approaches. They don’t necessarily seek what’s falsifiable (a la Karl Popper), and are not always looking to verify hypotheses. They are often poking around, trying to find something.  And yet they still produce science that’s valuable and reproducible. Later, when he mentions that science, like all human behaviour, is not only determined by rational thought but by social context, the interviewer takes exception, “Aren’t you stoking the fires of people like climate change deniers?” Moriarty countered that although he looked at some of the evidence for man-caused climate change and found it strong, he is ultimately convinced of the phenomenon by having faith in specialists’ opinions.

Although Moriarty doesn’t delve into the issue, what’s relevant is that it’s also perfectly reasonable and necessary to consider conflicts of interest. What makes man-caused climate change increasingly convincing to the majority, is that it has far less hidden and/ or dubious motives than those of the skeptics. It is for the same reason that I take the President’s Cancer Panel seriously when they concluded in 2010:

“the true burden of environmentally induced cancers has been grossly underestimated” and strongly urged action to reduce people’s widespread exposure to carcinogens.

Postcript: An interesting interview regarding BPA and regulatory agencies was aired on Public Radio International’s Living Earth