Category Archives: Good Science

Environmental negligence part 1: Leaded gasoline

Before I start this post, I just want to say that I hope you are all doing okay with regard to the spread of coronavirus. It is important that we take this situation seriously in effort to minimize the risk to yourselves and others.

As a professional scientist, I have to admit that I sometimes struggle with technology’s dual nature. I realize that studying physics and being able to come up with ideas to test in the laboratory is an enormous privilege. But scientific knowledge also comes with substantial weight.

Probably the biggest challenges facing humanity today, environmental damage and climate change, have partly arisen due to the outgrowth of technologies related to the study of electromagnetism and thermodynamics in the 19th century. Eliminating greenhouse gas emissions is a monumental task that is nuanced with all sorts of moral issues that relate to the developing world. In particular, the developing world has not been primarily responsible for much of the anthropogenic greenhouse gasses we see in our atmosphere today, but will likely end up seeing their development stunted as the world attempts to cut emissions.

In this series of posts, I raise some questions pertaining to how we as a society here in the US have dealt with environmental issues in the past and identify a few patterns of behavior. Specifically related to this, I ask whether there exist deep-rooted structural problems and whether there exist options to fix them. I focus on three particular examples (among many!), that of leaded gasoline, chloroflourocarbons (CFCs) and PFOA (Teflon) to illustrate the difficulties in fighting environmental damage, but also how there is some hope in doing so.

For thousands of years, lead has been used for many purposes, most famously for pipes and aqueducts in the Roman empire. Although even the Romans were aware of the toxicity of lead, they continued to use it. Thus, lead poisoning has been in the public consciousness for at least a couple thousand years. In the US, it was thought that low levels of lead exposure did not pose a serious health risk, however. For example, lead had been used in paint for centuries. In the early 1920s, though, something changed. Lead made its way into the air we breathe through the automotive industry as an additive to gasoline due to its anti-knock properties. It was this use of lead, as a gasoline additive, that put lead basically everywhere in the atmosphere and surface ocean water. Despite the well-known health risks of lead to the general public, there were no studies conducted by any government agency or by any of the companies before sales of leaded gasoline were permitted in the marketplace.

Just a couple years after tetraethyl lead (TEL) was included in gasoline, workers at the company producing leaded gasoline (Ethyl Gasoline Corporation, a joint venture between General Motors, DuPont and Standard Oil) started suffering consequences. Some died, some “went crazy” because lead is a neurotoxin and others showed significant mental deterioration. Alexander Gettler and Charles Norris, a toxicologist and the Chief Medical Examiner of New York, were tasked with performing autopsies on four of the workers that had died in relation to work at the company. Their report, published in 1925, showed significant levels of lead in the brain tissue of the victims, more so than in patients that exhibited conventional lead poisoning (i.e. not from TEL). They speculated that the lead in TEL was somehow attracted to brain tissue more than regular lead.

Around the time of their report, New York, New Jersey and the city of Philadelphia all banned the sale of leaded gasoline. Also in 1925, the U.S. Surgeon General formed a task force with the intention of performing a more thorough investigation of the effects of lead on the population, though excluded Gettler and Norris from the committee. Around the same time, Thomas Midgley Jr., one of the inventors of TEL and a scientist at the Ethyl Gasoline Corporation, published a paper on the lack of hazards posed by leaded gasoline to the general public. I hesitate to even mention that this was a massive conflict of interest. In addition to this paper, there were heavy propaganda efforts aimed at the public to make it seem like leaded gasoline was a huge step forward in the automotive industry. Below are a couple examples of advertisements from 1927 and 1953 respectively (notice how lead is never mentioned):

The U.S. Surgeon General ultimately sided with Midgley and industry insiders, citing a single short seven-month study that showed a lack of evidence that TEL was causing harm. The federal government lifted all bans on the sale of leaded gasoline. In a rather foreboding gesture, the task force did acknowledge the possibility that with more cars on the road in the future, the issue would have to be re-visited. This kicking of the can down the lead-coated road would last about 60 years. More about the Surgeon General’s report can be read here (PDF!).

One thing I should mention about the U.S. Surgeon General’s task force is that it abided by what became known as the Kehoe Rule, which puts the burden of proof on showing that leaded gasoline is unsafe. This is in contrast to the precautionary rule, which puts the burden of proof on showing that leaded gasoline is safe if introduced into the public arena.

How did leaded gasoline ultimately get banned from use? This is where the story takes an unlikely turn. Enter Clair Patterson, a geochemist working on trying to date the age of the Earth. At the recommendation of his PhD advisor, Patterson started working on trying to figure out the ratio of lead to uranium in old rocks, as uranium-238 would eventually decay into lead after 4.5 billion years. What Patterson found was startling. He was basically finding lead contaminants everywhere. Whatever rock he looked at, no matter how clean his laboratories were, would always be contaminated. He started to figure out that everything in his lab was contaminated with lead. Distilled water, glassware, you name it, was contaminated. This prevented him from obtaining the correct ratio.

Because of this contamination, Patterson spent years building the world’s first “cleanroom”, that would be lead-free. Below is a rather inspiring image of Clair Patterson scrubbing the lab floor (taken from here):


With his massive effort to create a lead-free zone, Clair Patterson was ultimately able to obtain to the age of the earth: 4.5 billion years. But this isn’t what this story is about.

After going to such lengths to fight off lead contamination, Patterson realized where the lead was coming from. In 1965, Patterson tried to convince the public that leaded gasoline was a major health hazard by publishing Contaminated and Natural Lead Environments of Man. Even though he was the world’s foremost expert on the topic at the time, he was left off a National Research Council research effort to study lead in the atmosphere in 1971. See a pattern (see above about Gettler and Norris)? Once Patterson turned his studies toward lead contamination in food, it became abundantly clear that lead was present in every facet of life on earth.

For his efforts, Patterson was hounded by industrial insiders and refused contracts with many research organizations. But ultimately, he did win his long-fought battle. He was massively helped in this battle by Herbert Needleman, who performed research showing that long exposure to lead in children likely resulted in a lower mental capacity. In 1986, the US phased out leaded gasoline, more than 65 years after the first warnings were put out by scientific watchdogs.

There is much to learn from this particular story, but before I go onto conclude, I would like to recap a couple more historical anecdotes in the days to come that I think we can learn from. More to follow…


*Much of this post was learned through the following references:

Looney Gas and Lead Poisoning: A Short, Sad History


Book Review – The Gene

Following the March Meeting, I took a vacation for a couple weeks, returning home to Bangkok, Thailand. During my holiday, I was able to get a hold of and read Siddhartha Mukherjee’s new book entitled The Gene: An Intimate History.

I have to preface any commentary by saying that prior to reading the book, my knowledge of biology embarrassingly languished at the middle-school level. With that confession aside, The Gene was probably one of the best (and for me, most enlightening) popular science books I have ever read. This is definitely aided by Mukherjee’s fluid and beautiful writing style from which scientists in all fields can learn a few lessons about scientific communication. The Gene is also touched with a humanity that is not usually associated with the popular science genre, which is usually rather dry in recounting scientific and intellectual endeavors. This humanity is the book’s most powerful feature.

Since there are many glowing reviews of the book published elsewhere, I will just list here a few nuggets I took away from The Gene, which hopefully will serve to entice rather than spoil the book for you:

  • Mukherjee compares the gene to an atom or a bit, evolution’s “indivisible” particle. Obviously, the gene is physically divisible in the sense that it is made of atoms, but what he means here is that the lower levels can be abstracted away and the gene is the relevant level at which geneticists work.
    • It is worth thinking of what the parallel carriers of information are in condensed matter problems — my hunch is that most condensed matter physicists would contend that these are the quasiparticles in the relevant phase of matter.
  • Gregor Mendel, whose work nowadays is recognized as giving birth to the entire field of genetics, was not recognized for his work while he was alive. It took another 40-50 years for scientists to rediscover his experiments and to see that he had localized, in those pea plants, the indivisible gene. One gets the feeling that his work was not celebrated while he was alive because his work was far ahead of its time.
  • The history of genetics is harrowing and ugly. While the second World War was probably the pinnacle of obscene crimes committed in the name of genetics, humans seem unable to shake off ideas associated with eugenics even into the modern day.
  • Through a large part of its history, the field of genetics has had to deal with a range of ethical questions. There is no sign of this trend abating in light of the recent discovery of CRISPR/Cas-9 technology. If you’re interested in learning more about this, RadioLab has a pretty good podcast about it.
  • Schrodinger’s book What is Life? has inspired so much follow-up work that it is hard to overestimate the influence it has had on a generation of physicists that transitioned to studying biology in the middle of the twentieth century, including both Watson and Crick.

While I could go on and on with this list, I’ll stop ruining the book for you. I would just like to say that at the end of the book I got the feeling that humans are still just starting to scratch the surface of understanding what’s going on in a cell. There is much more to learn, and that’s an exciting feeling in any field of science.

Aside: In case you missed March Meeting, the APS has posted the lectures from the Kavli Symposium on YouTube, which includes lectures from Duncan Haldane and Michael Kosterlitz among others.

Discovery vs. Q&A Experiments

When one looks through the history of condensed matter experiment, it is strange to see how many times discoveries were made in a serendipitous fashion (see here for instance). I would argue that most groundbreaking findings were unanticipated. The discoveries of superconductivity by Onnes, the Meissner effect, superfluidity in He-4, cuprate (and high temperature) superconductivity, the quantum Hall effect and the fractional quantum Hall effect were all unforeseen by the very experimentalists that were conducting the experiments! Theorists also did not anticipate these results. Of course, a whole slew of phases and effects were theoretically predicted and then experimentally observed as well, such as Bose-Einstein condensation, the Kosterlitz-Thouless transition, superfluidity in He-3 and the discovery of topological insulators, not to diminish the role of prediction.

For the condensed matter experimentalist, though, this presents a rather strange paradigm.  Naively (and I would say that the general public by and large shares this view), science is perceived as working within a question and answer framework. You pose a concrete question, and then conduct and experiment to try to answer said question. In condensed matter physics, this often not the case, or at least only loosely the case. There are of course experiments that have been conducted to answer concrete questions — and when they are conducted, they usually end up being beautiful experiments (see here for example). But these kinds of experiments can only be conducted when a field reaches a point where concrete questions can be formulated. For exploratory studies, the questions are often not even clear. I would, therefore, consider these kinds of Q&A experiments to be the exception to the rule rather than the norm.

More often then not, discoveries are made by exploring uncharted territory, entering a space others have not explored before, and tempting fate. Questions are often not concrete but posed in the form, “What if I do this…?”. I know that this makes condensed matter physics sound like it lacks organization, clarity and structure. But this is not totally untrue. Most progress in the history of science did not proceed in a straight line like textbooks make it seem. When weird particles were popping up all over the place in particle physics in the 1930s and 40s, it was hard to see any organizing principles. Experimentalists were discovering new particles at a rate with which theory could not keep up. Only after a large number of particles had been discovered did Gell-Mann come up with his “Eightfold Way”, which ultimately led to the Standard Model.

This is all to say that scientific progress is tortuous, thought processes of scientists are highly nonlinear, and there is a lot of intuition required in deciding what problems to solve or what space is worth exploring. In condensed matter experiment, it is therefore important to keep pushing boundaries of what has been done before, explore, and do something unique in hope of finding something new!

Exposure to a wide variety of observations and methods is required to choose what boundaries to push and where to spend one’s time exploring. This is what makes diversity and avoiding “herd thinking” important to the scientific endeavor. Exploratory science without concrete questions makes some (especially younger graduate students) feel uncomfortable, since there is always the fear of finding nothing! This means that condensed matter physics, despite its tremendous progress over the last few decades, where certain general organizing principles have been identified, is still somewhat of a “wild west” in terms of science. But it is precisely this lack of structure that makes it particularly exciting — there are still plenty of rocks that need overturning, and it’s hard to foresee what is going to be found underneath them.

In experimental science, questions are important to formulate — but the adventure towards the answer usually ends up being more important than the answer itself.

Citizen First, Scientist Second

I have written previously in praise of the scientific community becoming more diverse over time. I emphasized its importance because people with different cultural backgrounds often synthesize ideas that are sometimes not juxtaposed in other cultures. It is almost unquestionable that the US scientific enterprise has benefited greatly from the inclusion of scientists from around the world. Because the scientific community has become more diverse in the past few decades, it has also meant that science (at least in the academic sense) has become more open and international. As a member of the international community myself (I am a Thai citizen), recent events have been tough to watch as a scientist, immigrant and person.

This past week has seen some, I would consider, unsavory events affecting the scientific and higher education communities in the US. There was a temporary ban put in place by the US government barring citizens from seven Middle Eastern and African countries from entering the US. Some students are stranded outside the US, unable to return before the spring semester starts.

Day to day, science requires enormous attention to detail, patience doing precise theoretical or experimental work, and time to work without distractions. It is easy to get wrapped up in one’s own work, forgetting to pick one’s head up to look at what is going on around you. If events are not directly affecting you or someone close to you, it is easy to forget that these things are even happening.

In this spirit, I encourage you to attend (or organize!) department town hall meetings and speak up in support of your international colleagues. There is a planned Scientists’ March being arranged, and I urge you to attend if there is a gathering near you. To be perfectly honest (like most scientists), I am a person of thought rather than a person of action, but it is always necessary to be a citizen first and a scientist second.

An Interesting Research Avenue, an Update, and a Joke

An Interesting Research Avenue: A couple months ago, Stephane Mangin of the Insitut Jean Lamour gave a talk on all-optical helicity-dependent magnetic switching (what a mouthful!) at Argonne, which was fascinating. I was reminded of the talk yesterday when a review article on the topic appeared on the arXiv. The basic phenomenon is that in certain materials, one is able to send in a femtosecond laser pulse onto a magnetic material and switch the direction of magnetization using circularly polarized light. This effect is reversible (in the sense that circularly polarized light in the opposite direction will result in a magnetization in the opposite direction) and is reproducible. During the talk, Mangin was able to show us some remarkable videos of the phenomenon, which unfortunately, I wasn’t able to find online.

The initial study that sparked a lot of this work was this paper by Beaurepaire et al., which showed ultrafast demagnetization in nickel films in 1996, a whole 20 years ago! The more recent study that triggered most of the current work was this paper by Stanciu et al. in which it was shown that the magnetization direction could be switched with a circularly polarized 40-femtosecond laser pulse on ferromagnetic film alloys of GdFeCo. For a while, it was thought that this effect was specific to the GdFeCo material class, but it has since been shown that all-optical helicity-dependent magnetic switching is actually a more general phenomenon and has been observed now in many materials (see this paper by Mangin and co-workers for example). It will be interesting to see how this research plays out with respect to the magnetic storage industry. The ability to read and write on the femtosecond to picosecond timescale is definitely something to watch out for.

Update: After my post on the Gibbs paradox last week, a few readers pointed out that there exists some controversy over the textbook explanation that I presented. I am grateful that they provided links to some articles discussing the subtleties involved in the paradox. Although one commenter suggested Appendix D of E. Atlee Jackson’s textbook, I was not able to get a hold of this. It looks like a promising textbook, so I may end up just buying it, however!

The links that I found helpful about the Gibbs paradox were Jaynes’ article (pdf!) and this article by R. Swendsen. In particular, I found Jaynes’ discussion of Whifnium and Whoofnium interesting in the role that ignorance and knowledge plays our ability to extract work from a partitioned gases. Swendsen’s tries to redefine entropy classically (what he calls Boltzmann’s definition of entropy), which I have to think about a little more. But at the moment, I don’t think I buy his argument that this resolves the Gibbs paradox completely.

A Joke: 

Q: What did Mrs. Cow say to Mr. Cow?

A: Hubby, could you please mooo the lawn?

Q: What did Mr. Cow say back to Mrs. Cow?

A: But, sweetheart, then what am I going to eat?