Demonstrating polymer entanglement

From Steve Spangler I learnt this "party trick" demonstration of how the polymer molecules (polyethylene) in a plastic bag are entangled with one another. 

I was not sure that it would work as easily as it did for him. But it did!

de Gennes enthuses about Chemistry and skewers Comte

Pierre-Gilles de Gennes (1932-2007) was arguably the founder of soft matter as a research field, as recognized by the Nobel Prize in Physics in 1991. After this de Gennes gave many lectures in French high schools, which were then published as a book, Fragile Objects: Soft Matter, Hard Science, and the Thrill of Discovery. Previously, I mentioned the book with regard to whether condensed matter physics is too abstract.

 One of many fascinating sections of the book is a chapter entitled, The Imperialism of Mathematics. de Gennes sings the praises of chemistry, and rants about the weaknesses of the French system, laying the blame at the feet of his compatriot Auguste Comte (1798-1857). Comte was one of the first philosophers of modern science and a founder of sociology and of positivism.

Below I reproduce some of the relevant text. When reading it bear in mind that de Gennes was a theoretical physicist and did work that often involved quite abstract mathematics and concepts.

        THE "AUGUSTE COMTE" PREJUDICE

I now come to a prejudice typical of French culture, inherited from the positivism of Auguste Comte. This nineteenth-century philosopher achieved some degree of fame by inventing a classification system of the sciences. 

At the top of his hierarchy was mathematics; at the bottom was chemistry, which according to him "barely deserved the name of science"; in the middle were astronomy and physics. This classification dismissed out of hand geography and mineralogy, sciences which were declared concrete and descriptive, retaining only those that were theoretical, abstract, and general. The tone was set! It is ironic that this philosophical concept came from an individual who had once written in a letter "The only absolute truth is that everything is relative," and who claimed to be steeped quasi-religiously in factually observable laws, in other words, laws verifiable by experiments. 

The "Auguste Comte" prejudice corrupts to this day the teaching of the sciences, the scientific disciplines, and even the scientists themselves. It also contains the seed of contempt for manual labor, which has interfered for years by curbing every attempt at reform to revalue the manual trades and their apprenticeship... 

An example comes to mind, of some graduates of the Polytechnic School of Paris attending an advanced program at Orsay to learn solid-state physics. They would often show up convinced that they knew everything on the basis of calculations. 

... But the typical Polytechnic graduate I inherited at the time would remain stumped in front of his bare blackboard. One of them finally blurted out (I will never forget his comment): "But, sir, what Hamiltonian should I diagonalize?" He was trying to hang on to theoretical ideas which had no connection whatsoever with this practical problem. This kind of answer explains, in large part, the weakness of French industrial research.

Among all the catastrophes brought about by the positivist prejudice, none is worse than the widespread contempt for chemistry. I have already pointed out the importance of this discipline for our industrial future, the importance of chemists, these marvelously inventive sculptors of molecules, to whom the French teaching establishment does not do nearly enough justice. An undergraduate math major once told me about a teacher who, on opening day, announced: "I personally dislike chemistry, but I have to talk about it. So, I will start by giving you two hours of chemical nomenclature: what the name of an obscure and com- plex molecule is, and the like." At the conclusion of the two hours, the entire class was turned off chemistry for life!

When Lucien Monnerie, the director of studies, and I took over re- sponsibility for courses at the Institute of Physics and Chemistry, we had to wage a determined battle to overcome the antichemistry prejudice. Just before our arrival, the students had organized a strike: they all wanted to become physicists. Slowly, we climbed back up the slope with a series of measures: changing labels, opening up several new channels, turning the entire curriculum upside down, and launching a verbal propaganda campaign. It was rather easy for me to sound persuasive; being a theoretical physicist, nobody could accuse me of protecting my own turf. But it took us 10 years to restore the proper balance. 

To anyone who wants to form a more precise idea of chemistry, of the life of a typical chemical engineer, I would advise reading the magnificent collection of essays by Primo Levi, The Periodic Table. They recount real-life stories. They possess an authenticity and a vitality which give a universal impact to the account of an ordinary fact, the description of minute events. It is an excellent antidote to the poison spread by Auguste Comte's classification scheme.

Is condensed matter physics too abstract?

Condensed matter physics is about the properties of real materials. Real stuff that you can see and touch and that you can use to make very practical things like TV screens and mobile phones. Yet, I find it fascinating and somewhat ironic that in condensed matter theory very abstract ideas and mathematical techniques keep cropping up (and being extremely useful): variable spatial dimensions, imaginary frequencies, topology, Chern numbers, conformal invariance, ...

Yet, there is a danger with abstraction. Theoretical condensed matter is not pure mathematics. Perhaps, too often fancy and beautiful mathematics is prized over physical intuition and insight. Theory may take precedence over experiment. How does one find the appropriate balance?

This is part of broader issues about the role of abstraction and formality in education.

Pierre de Gennes (1932-2007) was arguably the founder of soft matter as a research field, as recognized by the Nobel Prize in Physics in 1991. He began his career working on superconductivity and went on to develop a unified framework to understand soft matter (liquid crystals, polymers, foams, colloids...), introducing ideas such as order parameters, scaling, renormalisation, and universality.

After his Nobel, de Gennes gave many lectures in French high schools, which were then published as a book, Fragile Objects: Soft Matter, Hard Science, and the Thrill of Discovery. I highly recommend it, both as a popular introduction to soft matter, but also to hear the perspective of a great scientist on education and research.

de Gennes spent almost his whole life living and working in France. In the book he rants about the French system, particularly its obsession with entrance exams, mathematics, formality, and the abstract.

“Manual skills, visual acumen, the sense of observation, an interest for the physical world which surrounds us, are all qualities that are neglected or downgraded.”

“To work in a garage seems to me the best initiation to a professional life.”

“Ignorance of the real world causes grave distortions.”

“the positivist prejudice”

I found this fascinating because one thing de Gennes is famous for is showing how some properties of a polymer can be understood by considering a theory involving a vector of dimension n, where n was a continuous variable, in the limit where n approaches zero! That is pretty abstract! But, I guess the point is that he is not against abstraction, exams, and mathematics, per se. Rather, he is against them taking on a life of their own.

de Gennes concerns are also shared by Henri Alloul (well known for beautiful NMR experiments on strongly correlated electron materials) author of Introduction to the Physics of Electrons in Solids. In the Preface, he writes, 

In many countries, teaching traditions have always given pride of place to a formal, and essentially deductive, presentation of the physics, i.e., starting from formal hypotheses and leading up to observable consequences. This deductive approach leaves a purely a posteriori verificational role to observation, and hides the thinking that has gone into building up the models in the first place. Here we shall adopt the opposite approach, which begins with the fact that in science in general, and in solid state physics in particular, the qualitative understanding of a phenomenon is an important step which precedes the formulation of any theoretical development. We thus urge the reader to carry out a careful examination of the deeper significance of experimental observations, in order to understand the need for specific models and carry out realistic approximations.

The debate about abstract mathematics is also central to contrasting views about the Institute for Advanced Study at Princeton.

de Gennes's views would have also resonated with Harry Kroto who shared The Nobel Prize in Chemistry for the discovery of buckyballs. He credited playing with Meccano as a child as very important in his scientific development.

Sweet demonstrations of phase transitions

This week my wife and I did some science experiments with kids, aged about 8-12, at a holiday kids club organised by our church. The first day we did rockets, using the old standbys of baking soda rockets and mentos and coke.

On the second day, we did the science of chocolate. Ten years ago (!) we had done this based on some demonstrations developed at Harvard, described in this paper The Science of Chocolate: Interactive Activities on Phase Transitions, Emulsification, and Nucleation. 

Teaching kids about phase transitions with ice and steam is not quite as exciting or memorable as them melting chocolate in their mouths. An important scientific idea is:

Physical properties of matter (such as melting temperature) change with differences in chemical composition.

This is illustrated by the different melting temperatures of white, milk, and dark chocolate.

We also tried to mix water and oil, with and without the presence of detergent. This illustrates ideas about emulsification, including hydrophobic interactions. This is relevant to the production of nice smooth and uniform chocolate because the cocoa powder can only dissolve in the cocoa butter when an emulsifier is present.

Discussing chocolate is also an opportunity to discuss Milton Hershey (USA) and the Cadbury family (UK). They were not only philanthropists but were proactive in taking care of employees and their families, e.g. constructing schools, parks, and affordable housing. Richard and George Cadbury developed the garden village of Bournville; now a major suburb of Birmingham. I particularly like this sentence in the Wikipedia entry on George Cadbury, showing how he was far ahead of his time.

In 1901, disgusted by the imperialistic policy of the Balfour government and opposed to the Boer War, Cadbury bought the Daily News and used the paper to campaign for old age pensions and against the war and sweatshop labour.^[4]

Other scientific articles of interest include the following. The first two discuss how there are six different polymorphs (crystal structures) of chocolate. The competition between these states comes into play with tempering, snapping, shine, and smoothness. [Aside: In general, calculating the relative energies of different polymorphs of molecular materials is a major scientific challenge.]

Chocolate: A Marvelous Natural Product of Chemistry, Ginger Tannenbaum

Using Differential Scanning Calorimetry To Explore the Phase Behavior of Chocolate Michael J. Smith

The kitchen as a physics classroom Amy C Rowat, Naveen N Sinha, Pia M Sörensen, Otger Campàs, Pere Castells, Daniel Rosenberg, Michael P Brenner and David A Weitz

The most essential critical thinking skill for citizens?

 I believe that there is one verb that describes the mission of universities (think) and that teaching a discipline means teachings students how to think in accord with that discipline.

But, what about high school? What are the key critical thinking skills that all students should learn? In particular, what is needed they can become engaged citizens who play a constructive role in a democracy.

I wonder if the most essential skill is to be able to consider an issue and critically evaluate different perspectives on the issue. Consider issues that are often topics of public debate (and acrimony): taxation, immigration, government regulation, freedom of speech, funding health care, covid lockdowns, capitalism, socialism, ... 

These are all complex issues and there is a wide range of perspectives on each of them. First, a student (citizen) should be able to acknowledge the existence of different perspectives. Second, objectively identify (or at least understand) the essential content of the different perspectives. Third, identify (or at least understand) the strengths and weaknesses of each of the perspectives, including acknowledging the level of evidence including its uncertainty. Fourth, compare and contrast these strengths and weaknesses. Fifth, be able to make the case for the perspective they may prefer. This may be too ambitious. But, it is a desirable goal.

I should point out that I am not at all proposing something postmodern/relativist along the lines of "all views are equally valid" or that "all views should get equal air time." Rather, such exercises and skills should lead to the ability to see why extremist and crackpot views should not get the attention or credibility that too often they do.

How does one achieve this? A concrete example is provided by an Indian newspaper presents opinion columns with Left, Right, and Centre views on specific issues.

There is a related but distinct skill that all citizens should desirably have, empathy, i.e. the ability to put oneself in the shoes of another (their context, background, and life experience) and see why they hold the views they do. This is more of an emotional skill, rather than an intellectual one. This skill enables one to understand and communicate better with those who have wildly different views than our own.

What do you think? What critical thinking skills do think should be promoted? What is realistic?

The mental health crisis among university students is going to get worse

For the past few months I have been travelling in North America and the UK, for a mixture of work and holiday. In a range of professional and social settings I have had conversations with different people associated with universities: faculty, students, parents, and NGOs. It is amazing (and disturbing) how many times one subject keeps coming come up: student mental health problems. It was never me who brought up the subject and I don't think any of the people who did bring it up knew that I am interested in the issue, partly because of my own struggles. Two important questions people have asked are:

Has the incidence of student mental health problems increased or is it just that reporting of problems has increased?

Is the situation likely to improve in the near future?

Unfortunately, I think the problems have substantially increased and that they unlikely to decrease in the near future. I hope I am wrong. But, I think that there are a multitude of inter-related social, economic, and political changes that form a toxic cocktail for students.

To illustrate the extent of the problem and some of the compounding issues it is worth reading these two articles, both of which almost have a (tragic) surreal feel.

Why are suburban super-students burning out in college? These Main Line therapists say anxiety is high – and all around us
Philadelphia Inquirer

Feeling Suicidal, Students Turned to Their College. They Were Told to Go Home
New York Times
[Comments are worth reading too]

What are the origins of the crisis?
I think it may be a combination of the factors below. In isolation I doubt one or two of them would create such a large problem, but when you put many together, life starts to get very difficult. To what extent you think some of them is a problem may also depend on what you believe is "normal" and "healthy". The factors are listed in random order. Some are inter-related.

A winner takes-all society.
Everyone wants to be a winner and a celebrity. But most people are not. At the crass level, this cultural shift is reflected in TV shows involving singing or cooking competitions. It is also reflected in increasing economic inequality,  where the wealth of the upper class (the one per cent) is increasing dramatically and the lower middle class is ballooning, including graduates with massive debts from student loans. The pressure to succeed is immense and the despair of "failure" is greater.

Social media.
Students are comparing themselves to their "friends" and struggling to project a perfect and successful life. Interpersonal conflict is escalated because social media is a flawed medium for civil and meaningful communication. Rather that talking to other students before or after class students are staring at their phones.

Frustration from or fear of unfulfilled expectations.
University marketing departments portray life on campus as a collection of beautiful young people sitting around on lawns on bright sunny days having meaningful conversations before they graduate to high-paying and fulfilling jobs. A student at an over-crowded state university soon discovers they are sitting in a lecture hall with hundreds of students and no one seems to care whether they are there or not. Although they were told their degree would be a launching pad for a "career", many discover it is actually hard to get any sort of job, let alone something related to their major. No wonder they are depressed!

Excessive screen time.
It is bad for your brain and addictive. You get overstimulated. For some there is addictive content such as on-line games and pornography. It cuts into time for personal relationships.

Breakdown of family life.
Parents are increasingly absent, whether literally, emotionally, or practically, while children are growing up. This decreases students sense of identity, stability, ability to navigate life, including form meaningful relationships, and resolve conflict.

Alcohol and drug abuse.
This may actually be decreasing. However, it is still rampant, and compounds all of the other problems. Furthermore, mental health problems and substance abuse become intertwined.

Sexual harassment and assault.
Reporting has certainly increased. Again, the prevalence of this problem compounds all of the issues above.

What do you think? Have the problems increased? If so, what are the causes?

Basic introductions to Condensed Matter Physics

Suppose a motivated and intelligent high school student or first year undergraduate comes to you and says, ``Condensed matter physics sounds really cool! What should I read or look at to learn more about it?"

Obviously, suggesting the student look at classic graduate texts such as Ashcroft and Mermin or Chaikin and Lubensky is not helpful. They need something that will inspire them to want to learn more as well as introduce them to some of the basic ideas and topics.

I would suggest the following.

David Pines, Unit 8 in Physics for the 21st Century, an on-line course
Emergent Behavior in Quantum Matter

Robert Laughlin, A Different Universe: Reinventing Physics from the Bottom Down

Stephen Blundell, Superconductivity: A Very Short Introduction

Rodney Cotterell, The Material World

But when then have read some of these it would be nice if the student could look at something more technical. To second year undergrads I give a series of lectures on Thermodynamics and Condensed Matter Physics. They don't need to know any quantum or stat. mech., just some thermo, and they can still get some of the flavour, excitement, and scope of the subject. But, I don't know a book that lays this material out clearly and simply. I draw on Schroeder, Thermal Physics, but it has no discussion of superfluids, order parameters, or symmetry breaking.

What do you think are good resources?

I thank Alex Agedah for asking this question.

Update. Here are some slides for a talk that Danielle McDermott gave on the subject. It lists many useful resources. (She mentions it in a comment below).

Who was the greatest theoretical chemist of the 19th century?

Dimitri Mendeleev, who proposed the periodic table of the elements, purely from phenomenology and without quantum mechanics!
He even successfully predicted the existence of new elements and their properties.

A friend who is a high school teacher [but not a scientist] asked me about how he should teach the periodic table to chemistry students. It is something that students often memorise, especially in rote-learning cultures, but have little idea about what it means and represents. It makes logical sense, even without quantum mechanics. This video nicely captures both how brilliant Mendeleev was and the logic behind the table.



A key idea is how each column contains elements with similar chemical and physical properties and that as one goes down the column there are systematic trends.
It is good for students to see this with their own eyes.
This video from the Royal Society of Chemistry shows in spectacular fashion how the alkali metals are all highly reactive and that as one goes down the column the reactivity increases.



The next amazing part of the story is how once quantum theory came along it all started to make sense!

A video illustrating the length scales of the universe

Sometimes when I speak about science to church groups I show the old (1977) video Powers of Ten which nicely illustrates the immense scale of the universe and orders of magnitude.
I often wished there was a more polished modern version.
Yesterday it was pointed out to me there is, Cosmic Eye.



The phone app can be purchased here for $1.

Science shows for kids

On sunday I went to the Science Street Fair hosted by the Aspen Science Center. It featured booths from a diverse range of organisations, many offering hands on activities for children.
I was on the look out for new ideas for demonstrations to do with kids. A new one for my dry ice repertoire is the smoke ring device featured in the video below.


There were public performances by Doctor Kaboom and Mr. Freeze from Fermilab.

One challenge of such performances is to go beyond "wow" and "gee whiz" to trying to teach something about how science works.
Dr. Kaboom tries to do this by testing a hypothesis about why the catapult was invented (video). However, I thought it was a little drawn out and was not sure if the point got through.

Mr. Freeze has a host of demonstrations based on liquid nitrogen. The one with the exploding cardboard box is pretty cool (video).

He also has a nice demonstration to show how the volume of a gas is about one thousand times larger than the volume of the liquid of the same amount of material. This involves using a 44 gallon garbage bag, shown below.

The demonstration is important and useful for at least two reasons.
For kids demonstrations this important fact is the key to many demonstrations involving rockets or explosions. One example, is baking soda rockets which are based on the production of CO2 gas.
For undergraduates, this thousand fold difference is the basis for using the Clausius-Clapeyron relation to explain why the slope of liquid-gas phase boundaries is much less than solid-liquid phase boundaries in pressure-temperature diagrams.

Trivia I learnt was that Fermilab uses thousands of gallons of liquid nitrogen per day, but this is less than McDonalds!

I find it a little ironic that one major part of Fermilab's public outreach involves condensed matter demonstrations.

The biggest challenge in education today?

This post was stimulated by attending a talk about (yet another) review of the curriculum in Australian schools. The talk and following discussion was conducted according to the Chatham House rule, which I had never encountered before.

Previously I wrote about the iron triangle in education: access, cost, and quality.

What is the role and significance of curriculum in education?
I think it is helpful to make some clear distinctions in roles, responsibilities, and desired outcomes.

1. Students learning.
This is what it is all about! It is important to distinguish this from students passing exams, attending lectures, or completing tasks.

2. Effective teachers.
They need to be passionate and competent, both about their subject and their students.

3. Curriculum and resources.
This also includes textbooks, course handbooks, online resources, buildings, libraries, equipment, laboratories, computers....

4. Policies and administrative procedures.
This includes hiring and firing, retaining, training, and rewarding teachers. Funding.
Paperwork. Oversight and accountability. Assessment/grading. Course profiles.

I think the biggest challenge in education today is to have a smooth and efficient flow from 4 to 1. Unfortunately, sometimes/often 4. and even 3. can actually hinder 2 and stymie 1.

I claim that doing 2, 3 and 4 well are neither necessary nor sufficient conditions for 1 to happen.

A good teacher is not sufficient for student learning. If the students are not motivated or do not have the appropriate background and skills, it does not matter how good the teacher is, the students won't learn.
Some students (admittedly a minority) can be even learn with a terrible teacher. If they are highly motivated and gifted they will find a way to teach themselves.
Great teachers can be effective without good textbooks or fancy buildings or career reward structures.
A great textbook and curriculum and fancy facilities won't help if the teacher is a dud.
Strong accountability structures with high quality testing and ranking of students, teachers, and schools do not guarantee learning. Teachers will teach to the test. Bad teachers and schools will put on an amazing show when they are "inspected.".

A major problem is that there are influential individuals, organisations, and bureaucracies that strongly believe (or pretend to believe) that 4 and/or 3 are necessary and sufficient for learning to happen. This leads to a distorted allocation of resources and heavy administrative burdens that are counter productive.

The challenge of improving education in the developing world

This video discusses the results contained in the Science article

The Challenge of Education and Learning in the Developing World
Michael Kremer, Conner Brannen, Rachel Glennerster

It uses the same approach of randomised trials that feature in the book Poor Economics.

Copper sulphate is a spin liquid

It is amazing since a common science project for school children is to make blue crystals of copper sulphate [CuSO4.5H2O]!
[Although I was surprised and disappointed when my son just told me he never did it].

Perhaps, one may not have to look so hard for quantum materials.

The first X-ray crystallography experiment [by von Laue] was also performed on copper sulphate pentahydrate.

It turns out that the Cu2+ ions (spin-1/2) form chains that are very weakly coupled to one another and so are effectively one-dimensional antiferromagnetic Heisenberg chains above the three-dimensional Neel ordering temperature of about 100 mK.
[Caveat: strictly speaking half of the Cu2+ ions form chains; the other half are essentially isolated and non-interacting].

Minor caveat: the relevant intrachain exchange interaction J ~ 0.25 meV and so one only sees the spinons for temperatures of order a Kelvin.

I first learned all this in the introduction of this Nature Physics paper.

Talk to high school students

Tonight I am giving a talk to a group of high school students.
They are attending the Queensland Junior Physics Olympiad (JPhO), which is organised each year by UQ Physics.

My brief was to give a basic introduction to my research. Here are the slides from my talk.
I have never given such a talk to a high school audience before.

One of the videos featured was an old BBC documentary on superfluids.

I recommended the following resources for people wanting to learn more:

David Pines article Emergent behavior in quantum matter

A video on Reductionism and emergence featuring Paul Chaikin and Piers Coleman

Bob Laughlin's book A Different Universe: reinventing physics from the bottom up.

Rocket science for children

Yesterday I did some science demos at a kids holiday club, using the Coke-Mentos fountain. Previous efforts led to the post Developing science demonstrations that actually teach science. It is fun and cool to do spectacular demonstrations that cause kids to go "Wow!" and think that science is "fun". But these also need to be a vehicle to teach something about critical thinking and the process of doing science.

Small initiatives can help. For example, I had one child record the height of each of the fountain, that was estimated by the group. This emphasized that measurement, error estimation, record keeping, and comparisons are key parts of doing science.

Aside: Yesterday I thought the Coke-Mentos fountain was higher than last time, particularly for diet Coke. I suspect the fact that is was a hot day helped, increasing the solubility of the carbon dioxide?

We also did Film canister rockets which the kids always enjoy.
I found it amusing that the kids ran off and told their friends they were doing "rocket science".

Developing science demonstrations that actually teach science

Demonstrations to school students can easily degenerate into the following format. First, one does something spectacular such as the Coke-Mentos fountain or the barrel crush. Second, one tells the student how it works. I confess I have often done this. However, this is actually terrible because it reinforces the misconception that science is a noun not a verb. It teaches nothing about the scientific method.

This week my wife and I demonstrated the Coke-Mentos fountain to a group of kids at a holiday club that my church was running. In order to promote critical thinking we did some comparative measurements. The fountain was done for diet Coke, Solo (a lemon drink), and generic brand (Coles) Cola. We also compared Mentos bought in the USA (on my recent trip) and in Australia. It turned out that the former is much more effective. I later learnt that we had been scooped in this important scientific discovery. It had already been published on YouTube!



I also discovered there is some nice literature on the subject.

Mentos and the Scientific Method: A Sweet Combination in the Journal of Chemical Education.

Diet Coke and Mentos: What is really behind this physical reaction? in the American Journal of Physics. They have some impressive apparatus for making quantitative measurements. They also found that playground sand was almost as good as Mentos.
They report surface analysis studies of the Mentos, highlighting the importance of the surface roughness for nucleation sites for CO2 bubbles.

The Ultrasonic Soda Fountain: A Dramatic Demonstration of Gas Solubility in Aqueous Solutions in the Journal of Chemical Education

“Can we do That Again?” Engaging Learners and Developing Beyond the “Wow” Factor in the Science Education Review.

Finally, having good apparatus helps. From Steve Spangler science we purchased a Geyser Tube which feeds the Mentos into the Coke. With the recommended 7 US Mentos we observed fountains of 2-3 metres!

Get expert feedback about your teaching

The Weekend Australian newspaper had an interesting article about the success of Asian high schools [particularly Shanghai, Hong Kong, Korea, and Singapore]. The article is largely based on a recent report from the Grattan Institute, an independent Australian think tank.

One thing the report emphasizes is the value of teachers getting feedback from their colleagues (and other expert classroom observers) about their teaching. At UQ we are increasingly being required/encouraged/expected to do this.

Teaching and assessing high school students

I recently learned something that greatly concerned me about high school education in Queensland. It seems teachers are not allowed to mark exams and assignments in the same manner we do at university. i.e. one gains or loses specific marks for specific actions such as getting the correct answer, including units in the calculation, stating what law or principle or equation one is using, drawing a relevant diagram. Instead, assessment is "criteria based". This means students get credit if teachers can tick off certain broadly based and pre-determined criteria, which seem to rarely get more specific than "using adequate quantitative reasoning". This significantly muddies the waters about right and wrong answers. Marking becomes a much more complicated exercise and more subjective.

I talked two physics and maths teacher about this and they agreed that it is ridiculous, but their hands are tied by the state government education bureaucracy.

I found learning this quite helpful because it may explain why increasingly I encounter students at university who cannot solve problems (especially in exam situations)  in the manner I expect.

To me this underscores the value of the International Baccalaureate as an alternative. There are now high schools in Brisbane (both public and private) which offer this as an option. I like it because it is internationally bench-marked and not subject to local political fashions.