omenti

getting to clean enough

It's becoming clear that the SARS-CoV-2 virus will be around for a long time.  We're probably much closer to the beginning than the end.   Hotspots will shift and new variants arise so it makes sense to be ready to mitigate risks as much as possible.  Vaccinating the world should be a high priority along with next generation vaccines, better treatments, testing, high quality masks when the risk is high, etc. etc.  

 

Improving local air quality is low hanging fruit.  To first order that means high quality masks in hotspots along with fresh air.   Room air filtration and circulation can be a powerful tool.  As living animals we exhale carbon dioxide.  In pristine location, say a mountain top in Hawaii, you can measure the baseline concentration. Air is about 420 ppm (parts per million) carbon dioxide - a bit over 0.04%.  Enclosed spaces with people have higher concentrations.  You're breathing some of the air from other people.  If people are the only source, you can calculate the percent of the total air in the room that's exhaled:

        CO₂ concentration (ppm)        % of total air that is exhaled 

                    420                                                  0%

                    600                                                0.5%  

                    800                                                1.0%

                    1000                                              1.5%

                    2400                                               5.0%

 

With these numbers it was believed the risk is low for up to an hour if everyone was wearing a simple cloth mask and one person was infected with the alpha variant with carbon dioxide concentrations as high as 800 ppm.  The delta variant changes the threshold.   Now the one hour number is about 600 ppm with everyone wearing a surgical mask.¹  Of course the probability of an infected person being in the room is low if you're in an area where the infection rate is low.  

 

It would be good to know the concentrations where ever you go:   offices, classrooms, stores, theaters, taxis, airplanes etc.²  Consumer grade carbon dioxide meters can be purchased for $100 to $300.  If you're really interested I can make a recommendation, but I've only used a few.  We'll probably see a rapid improvement as these are going to be essential tools.  Japan is requiring them in many public places and school rooms.³  It's important to have an NDIR sensor (basically it's doing spectroscopy with an infrared laser to measure concentration  - there are many other techniques, but this is the cheapest with enough accuracy and repeatability).  These are accurate to about 50 ppm, so ignore the more exact looking reading and just round up to the next multiple of 50  - if it reads 537 just call it 550.    It takes about two minutes to get a stable reading and you'll want one that stores measurements.  The model I like talks to an iPhone app which gives you a nice chart of the day.   For businesses and schools it's a good way to check if the rooms are getting good airflow.   I saw one schoolroom that exceeded 3000 ppm when students were present. It turned out an air return duct was blocked - a thirty minute fix gave the students clean air again.

 

High carbon dioxide concentrations make people drowsy and sap cognitive abilities.  It hasn't been carefully studied, but readings over 1000 ppm can make you drowsy and perhaps a bit feeble minded.  One Army study suggests 800 ppm should be a warning level.  Half-jokingly I told a superintendent that he could justify the cost of measurement though improved test scores.  It turned out that's what sold him.  Maybe it's a way to upgrade the collective intellectual capacity of an office.  Another benefit is a possible reduction in airborne diseases like the flu.  

 

You can't always open windows and doors to get a solid draft, but HVAC systems can often have their fan settings increased and room vents adjusted. High quality filters can capture viruses along with other particulate like some from a fire.  MERV-13 is a sweet spot for price,  the ability to snare virus sized particles and not requiring more powerful fans.  And you can buy or build portable air cleaners.

 

The hot ticket for rolling your own is a very simple design known as the Corsi-Rosenthal cube.  Here's the public domain diagram we used to build 84 of them for about $5,000  (the cost shown in the drawing doesn't involve much shopping around).  We used the cardboard from the shipping boxes the fans came in.  The shroud is very important.  Square corners disturb the airflow and can drop the unit's efficiency by about a third. A normal sized classroom for 30 to 40 students probably needs two units.  Keep them away from walls, doors,  and openable windows.  The filters will probably last the school year if you turn them off when people aren't in the room.  Most of the classrooms are showing readings under 600 ppm with these and the school's HVAC system fans all on high.  The boxes make a big difference.  Commercial air cleaners with good filters probably make more sense in offices and schools if they want to go long term, but 600 cfpm MERV-13 filters are about $500 and in short supply these days.   Like carbon dioxide meters I suspect we'll see some movement on air filter and fan design. 

 

Some learnings:

Duct tape is frustrating!

Schools have mountains of duct tape.

Eighth graders are the perfect people to enlist if you want to build a lot of them.  Eighth grade girls if you want them to be semi-presentable.

_________

¹ These are rule of thumb numbers based on empirical evidence.  But it's complex with many confounding factors. 

² A closed car can be spectacularly high. I sat in my car for fifteen minutes with one other person and recorded 3800 ppm!  You can drop this by opening the windows.  Opening them diagonally makes a lot of sense for creating airflow.  Airliners have good general circulation, but a given row can be bad.  A flight is probably much safer than a half hour Uber ride if the driver has the windows up.

³ People are already taking measurements in gyms, restaurants, etc and putting them online with locations and business names. It's ad hoc and not very standardized, but there are over 100 locations in NYC the last time I checked.  It makes much more sense for a business to do their air handling homework and post numbers in their establishment as well as their website.  Hopefully at some point a respectable aggregator will step in.

 

                                      

celebrating a friend

Sarah Pavan is a good friend who happens to be a world-class professional beach volleyball player.  In 2019 she and teammate Melissa Humana-Paredes were the world champions.  The video is of the semi-final match against Tokyo gold medalists April Ross and Alix Klineman.  Very high level volleyball in torrential rain for part of the time.  The ball behaves very differently went wet and there were more errors than normal, but also some terrific plays. Melissa injured her left shoulder early in the match, but was able to continue play.  Amazing volleyball from the best players.  There are video dropouts in the first few minutes, but that's before the match is underway.

 

The Canadians went on to silver and the Americans bronze the following day.

__________

 

Sport are an excellent vehicle for getting people engaged in science.  There's also a good deal of serious science involved and some open areas for work.

 

 

hints on how our brains adapt to deal with new concepts

Humans have seen an amazing progression of ideas from basic survival skills to getting a handle on how the universe began and might end and a great richness in between.  We do this with a brain that hasn't changed much in the past fifty thousand years.  How do we do it?

 

Here's a quick summary of some work at Carnegie Mellon University that used functional Magnetic Resonance Imaging as a probe to see how physicists organized conceptual properties.  fMRI is a rather blunt tool, but it was able to show how the brain organized the measurable and immeasurable.

 

Another striking finding was the large degree of commonality across physicists in how their brains represented the concepts. Even though the physicists were trained in different universities, languages and cultures, there was a similarity in brain representations. This commonality in conceptual representations arises because the brain system that automatically comes into play for processing a given type of information is the one that is inherently best suited to that processing. As an analogy, consider that the parts of one's body that come into play to perform a given task are the best suited ones: to catch a tennis ball, a closing hand automatically comes into play, rather than a pair or knees or a mouth or an armpit. Similarly, when physicists are processing information about oscillation, the brain system that comes into play is the one that would normally process rhythmic events, such as dance movements or ripples in a pond. And that is the source of the commonality across people. It is the same brain regions in everyone that are recruited to process a given concept.

 

There are a much broader range of deep concepts in physics that may well have separate organizations, but the technique here is very coarse.  They undoubtedly exist in many other occupations and one has to wonder how the mind of someone with a wide range of interests can dance around and play with different structures.  

 

Creative organizations need have internal access to a range of thinking modes and backgrounds. Like many others I have imposter syndrome when I'm listening to someone with deep experience in a different area.  Their mind has a great fluidity that you don't have became you lack the background and neural organization.  Breaking through this requires communicating at the appropriate level.  It's difficult if you don't know the other people.  One usually thinks of conventional academic subjects, but it's probably more general.  I find it amazing that some soccer or beach volleyball players create a mental map of the position, velocity, and acceleration of the other players including those they can't see and can bounce this off other information and communicate it to their teammate(s).  But great players run into the same problem as academic experts.  Finding the right level is difficult.  Great players rarely make great coaches.

 

Some organizations have worked out how to do this, but others tend towards narrow depth. If they appear to cover a broad range from the outside, inside they often are an array of poorly networked silos of local expertise.   Fortunately there seems to be a growing resistance to siloing.   And that brings me to a special kind of person.

 

Every now and again you come across a human impedance matches.  An impedance match is a bit of circuitry that allows as much of the signal as possible to go from sender to receiver (an over-simplification, but ...)  These people can sit between people with very different backgrounds or thought processes, often more than two, and make sure the signal gets through.    It astonishes me to see these people in action.  

 

breadth and depth

His parents were Danish, hers Swedish.  By some measures it was a mixed marriage with any number of small cultural differences. He noted and took delight in these small differences and ambiguities.  Rather than hunting, fishing or bowling he'd hike in the Summer and take long walks the rest of the year.   He liked to walk by himself and I suspect thinking about the stories he'd tell to friends and family about once a week.  He said storytelling was in his family and he had a great voice for it.      We'd sit in his yard and listen.   Some were short, some took a half hour.  They were imaginative with emotional moments coming in unsuspecting places.  They weren't the polished work of a writer, but left you wondering how he made those connections.  Only years later did I learn what an amazingly varied background he had and continually sought out.

 

My sister is a visual storyteller.  It took her half a lifetime to come to a place where she realized a single frame made of many images could be a short story that left you with questions and an open invitation to wonder.  She's extremely creative. The stories come to her quickly, but require a week or two to realize.  I suspect my Dad was a big influence.  He believed the best answers were incomplete and led to deeper questions.  He believed breadth was required to see simple answers weren't simple.  Corinne went for breadth, unfortunately I started down a path that was deeper than broad. 

 

A trigger for this post was a recent newsletter from David Epstein (The Sports Gene, Range).  He begins by talking about Emma Raducanu at the US Open:

Earlier this month, 18-year-old British tennis player Emma Raducanu won her first Grand Slam title. It was a shock; she entered the tournament with 400-to-1 odds. One of my favorite sportswriters, the Guardian’s Sean Ingle, asked Raducanu’s former coach about the factors that helped her talent blossom. Here’s what the coach said:

“From my perspective one of the best things with Emma is that she was exposed to a lot of sports from a young age, and didn’t go too specific into tennis straight away. I see that on court. When she’s learning a new skill, or trying something a little bit different, she has the ability and coordination to pick things up very quickly, even if it’s quite a big technical change.”

Raducanu added this:

“I was initially in ballet, then my dad hijacked me from ballet and threw me into every sport you could imagine. I was doing horse riding, swimming, tap dancing, basketball, skiing, golf and, from the age of five to eight, I was go-karting…From the age of nine I started motocross in a forest somewhere for a year. This was all alongside tennis.”

 

Although there are a few athletic geniuses like Tiger Woods who focus early, most elite athletes follow a very different path building a broad set of varied skills before specializing.   Epstein goes into depth in both of his books.  Outside of athletics, the generalists he focuses on in Range have richly diverse backgrounds. Something very different that the experience many have in trade school and college programs.  These people have built the tools they need to think creatively.  They're often better than narrow experts when confronted with a novel challenge.

 

 I'm sometimes asked to speak on the importance of STEM education at a local school and am doing it again.  I tell them STEM ok, but overemphasized in K12.  I think a broader liberal arts education leads to flexibility and creativity later on in life.  Unfortunately that isn't reflected in many (most?) hiring practices.  The lack of intellectual flexibility and diversity has lead to serous problems in some companies (tech in particular).   One can always add breadth later, but that can be inefficient once you're out of school.

 

I don't mean to disrespect STEM subjects.  Assuming the curriculum allows, they can be made relevant and exciting to those who won't use them in their work.   They add to breadth and can be a starting point for depth.   There are wonderful math and science books and teaching approaches that unlock wonder without getting bogged down in minutia.  Enough information and wonder that perhaps students will become citizens who can make informed choices.

 

Over the decades I've slowly broadened muself by talking to people and getting involved with their ideas and projects.  Many of you have your own diverse lists.  My short and incomplete list includes human powered airplanes, done strange things with sound, learned a little about animated film making, been around story tellers, learned a bit of anthropology and sociology, done art history research, learned about fashion and how clothes are made, learned a bit about diabetes, been involved in sandbending, the mental side of elite sport, and even know a bit about the fluid dynamics of balls used in sports.  Many of my guides and friends see this blog and I need to say thank you!   It amazes me how some of this triggers a thought in something I'm working on later.  You find yourself becoming more creative with age.  Who would have thought that the math for thinking about boundary layer separation on an almost non-spinning beach volleyball would help thinking about neutron star atmospheres.  Or the linkage between animation and fabric design, or...  the list goes on and on...   

 

Depth is great, but you need breadth to be creative.

 

 

sorting out what a product announcement means to you

Our neighbor left the box with my mother.  He was an Air Force Captain taken with building things of one kind or another.  During my Junior year in high school it was building electronic kits.  Back in the day that meant anything from Heathkit.  The company produced well-designed stereo components, oscilloscopes, an analog computer (long story, but my high school had one), test equipment, and amateur radio gear.  If you knew how to solder they were almost idiot-proof and you could repair them yourself when they broke.  A few of his old projects somehow made it to me.

 

It was a Heathkit AA-40 - a 40 watt per channel class A tube amplifier.  Unlike many of his gifts it still worked. The problem was I didn't have a turntable or speakers.  We had a family stereo, but touching it would have been socially dangerous.  I found an old turntable and a single very not very good speaker.  Anything moderately good was out of the question. Sometimes it's useful if you can't afford something.

 

I had read that the mass of the driven element, a speaker cone, was important.  Low mass meant high acceleration for a given force.  It made sense.  There were exotic electrostatic speakers with even lower masses than a cone.  Supposedly they sounded great, but had some technical issues.   It started me wondering if I could go to an even lower driven mass. 

 

A feature or flaw about me is I'm usually more interested in how something works than what it does or what it might do for me.  I thought ham radio would be exciting.  It turns out it was mostly people telling you how good your signal was, the weather and a few other boring things.  On the other hand how radio waves propagated through the atmosphere was fascinating and still is.  Faced with needing a speaker I was drawn to the basics.  It was just turning an electrical signal into a mechanical motion which would create a string of pressure differences in the air.  Speaker coils, magnets and paper cones.  On the other hand if I could make a plasma dance... 

 

I used a blow torch with a wick made out of asbestos (I know) that brought a salt solution into the flame.  Of course there was a background noise and it was a serious fire hazard, but you can't have everything at once.  The amplifier's output went into a high voltage transformer from a junked TV and into two electrodes in the flame.   It worked! The flame moved  in time to the music which was sort of identifiable as music.  It sounded terrible with the hiss and wasn't exactly safe for indoor use. But I've never been an audiophile, so it was an achievement in my book.

 

The same with a lot of technology.  It's deeply fascinating, but how chips are made and how semiconductors work seems more interesting than how I use them. And how people use technology is more interesting than how I use it.   (Sociology is way beyond me.)   There's a lot I'm interested in, but when it comes to personal adoption I tend to be in the middle and sometimes the trailing edge.  I'll buy something new,  like the first iPod or iPhone, and replace it every year until it does what seems useful.  Then I keep it until it fails or, like my old MacBook Pro, has a maddening keyboard.

 

I'm mostly in Apple's ecosystem so smartphone means iPhone to me. As time goes on I've made an effort to rely on it less and less.  It packs enough very useful features that I wouldn't go back to a pre-computer wireless phone, but my four year old phone is currently in a wait until it fails mode.

 

That said I follow Apple developer's conferences and product announcements.  The current iPhone 13 has a remarkable set of photographic and video capabilities.  Computational photography gets better every year and is now at stun level.   Apple is using the processor, graphics processor and machine learning hardware at the same time in some of the modes.   It's astounding.  If you're a serious photographer like Om or Bryan, you probably need one and have already ordered.  The device seems mature at this point.  They didn't make a big deal of it being faster, but rather concentrated on battery life.  Pro tip - mature portable electronics that check all of the feature boxes focus on battery life.  In the end user experience wins.

 

I'm not a photographer so a new iPhone would be overkill.  Maybe in a year what I have now will be unusable and I'll have something new.  How these things work and how they're built is the exciting part.  I would not have predicted some of the video features on the new phone. 

 

Horace Dediu has one of his always insightful pieces on the importance of the new iPhone.  In my case I'm probably a trailing edge user at this point - different from the much larger group Apple is addressing as they reinvent what the iPhone is useful for.  He's worth following if you have an interest in on person computational power and the micromobility revolution.

 

On the other hand Om may have nailed the really important product launch this season.  Then again, he offers an excellent iPhone 13 Pro review. 

 

 

 

some really big changes

event                    species eliminated     million years ago        cause(s)

End-Ordovician                       85%                 444                     global cooling  

Late Devonian                    70-80%          372-359                    multiple events, low O₂ in oceans    

End-Permian                      90-95%                 252                     volcanism

End-Triassic                            75%                  201                     volcanism

Cretaceious-Paleogene           75%                   66                      impact event, volcanism?                                              

 

In the late 70s a group led by Luis Alvarez found a very thin layer of an element that shouldn't be there in locations all over the Earth.  Iridium is very rare on the Earth, but common in meteorites and probably asteroids.  The layer was found in enough places that could be accurately dated.  Dinosaurs fossils were abundant below the layer and non-existent above it.  About three quarters of the species on Earth had vanished in a short amount of time.

 

It remained an interesting hypothesis until about a decade later when a 200 kilometer wide crater was mostly in the Gulf of Mexico and just happened to date to the end of the Cretaceious - about 66 million years ago.  It looked like the smoking gun, but any remnants of the asteroid were under layers and layers and layers of limestone.  But a few years ago what may just be the smoking gun was found.  The area around the crater has a large amount of high sulfur evaporate sedimentary rock. Drilling deep into the crater the sulfur-rich rock is mostly missing.  When the asteroid slammed into the earth so much energy was liberated that layers of this rock were vaporized.  In the atmosphere they combined with water and surrounded the Earth with a thick dark cloud layer that dramatically dropped the average temperature of the Earth.  For something like ten to twenty years temperatures on the land were near or below freezing. Not good if you're a plant. Not good if you're cold blooded and/or have a large enough body mass to require a lot of food.   

 

At the same time a large amount of carbon dioxide was emitted.  This probably helped preventing the temperature from going way below freezing, but it acidified the oceans killing a lot of marine life.   Land and ocean-based food chains were interrupted.  

 

The Chicxulub impact event is very compelling, but is it the whole story?

 

Perhaps not.

 

Around the same time, perhaps a few hundred thousand years earlier, something dramatic was underway in what is now Western India.  Four major volcanic events produced enormous lava flows collectively known as the Deccan Traps.  About a million cubic kilometers it would be enough to cover the US with about 120 meters of lava. Could it have been part of the extinction event?  After all, two of the major extinction events were volcanic and this one was approximately huge. (over three hundred times larger than the Yellowstone event)

 

Over twenty or thirty thousand years enough carbon dioxide was released to dramatically increase the Earth's temperature.  There's a growing consensus that it was part of the extinction event, although there's a lot of academic debate as to how important it was . Was life weakened by this increase and then finished off by the asteroid, or was most of the damage done by the eruptions?  A lot of interesting questions are being worked on.

 

The last extinction is relevant because at least one part of it was quick.  We're now at the beginning what appears to be the sixth extinction event.  The one we're causing and perhaps an extensional threat to humanity  It's also shaping up to be a very swift event. Learning how the atmosphere and oceans respond to such events is important. 

__________

Some of you know I've been trying to do something about global warning for about twenty years.  I've made another major change in approach.  I've never expected a major impact, but my first two approaches of education and storytelling have been failures.  I've moved on to targeted conversation.  Well beyond my pay grade, but in retrospect it appears to involve less titling at windmills.

 

 

on good design for those who need it

Olympian Sarah said she is more impressed by the achievements of Paralympians than Olympians.  She loves events like running with a guide and is particularly taken with goalball.  Goalball was invented after WWII for the blind.  The ball has two bells and the athletes have to use their sense of hearing to sort out where the ball is along with the other players.  It's stunning to watch.  (The first match is the gold medal match between the US and Turkey.)

There's a lot of interesting design in the Paralympics.  Sometimes the type of game, sometimes mechanical devices like special wheelchairs, and perhaps most important is a classification system to keep competition fair,  The amount of thinking that has gone into this puts many conventional sports to shame.  If you haven't watched any of the events go back and marvel at a few.  

 

Building proper access has been an uphill battle and people still fight against the Disabilities Act claiming it's "too expensive" or "just not worth it."  Getting the design right is a journey of its own.  A book that may change how you think about the built world is What Can a Body Do? by Sara Hendren. Solid recommendation!  This kind of design goes beyond physical affiances involving politics, law and sociology with the book addressing that and more.  The Paralympics are a shining example of it being done right in a limited area. 

 

This may seem a bit off topic, but I'd claim otherwise.  I've learned a lot from areas far from what I do.  Thinking about beach volleyball  led to a useful technique for studying neutron stars.   Get interested in something very different and you just might find interesting connections to something else.  Thinking about those with challenges is a rich area and probably useful for even non-designers to spend some time on.  It's a target-rich environment. 

 

 

the universe has it in for computers

a minipost

Cosmic rays have fascinated me since I was 13 and found a detector with a couple of patient physicists on the summit of Sulphur Mountain in Banff.   That was my first exposure to relativity.  I written a few posts on cosmics, but just say the word if you ever want to get me started on particles that can have the energy of a fastball and require detectors spread over thousands of square kilometers to properly detect.   Smashing into molecules in the upper atmosphere they produce large showers of elementary particles.  These can make it to the ground - or to a memory chip in a computer.  A direct hit on a memory cell can flip a bit from 1 to 0 without damaging the memory.  It's why you don't locate computer animation companies in Albuquerque or Denver.  It's why you use ECC memory in computers that run programs for more than a few hours and why many spacecraft have multiple radiation-hardened computers.   In addition to computer problems they're responsible for a large number of biological mutations.  They're one of many reasons why I think it's nutty to send humans into space beyond near Earth orbit. 

 

It's a very rich topic and this video by Derek Muller is an excellent introduction with historical examples of problems.  They've even interfered with an election. 

low distortion rearview mirrors

 

History Does Not Repeat Itself, But It Rhymes

      -  Mark Twain

Except it wasn't him.  

His clever and prolific writing made people assume he said it even though he never did.  It turns out it first appears around 1970 in a poem by a Canadian artist named Robert Colombo.  When asked if he knew where it was from Colombo couldn't recall other than he might have seen it in a literary section of the New York Times a few years earlier.  In fact it appears with and without attribution several times around the time of Colombo's poem in the early 70s.   That said, a hundred years from now people will still think Twain said it.

 

The process of science is much messier than the simple order kids learn in school.   There are too many dependancies to list.  A few philosophers of science  - notably Karl Popper and Thomas Kuhn - have tried to describe how scientific revolutions and change happens.  The how, where and why of scientific change.  Kuhn and Popper are somewhat at odds.  Kuhn's ideas were popularized and are still taught as how scientific revolutions happen.  It turns out that both of the frameworks are deeply flawed and have fallen from favor with serious students of the history and philosophy of science.  I came to it late, but I'm more a fan of an earlier step - trying to understand some of the history of science. 

 

Unfortunately the history of science is often neglected in scientific training.  Students are told a few selective stories from the great revolutionaries without much context.  Experiments, theories and techniques are described with little background.  The struggle and small steps forward and backward are  missing.  The world seems much too messy when you start doing real science on your own.  (this is probably true in many fields!)

 

One gets bits and pieces of local history from the last generation or two in their subfield.  This can be very powerful. I learned a lot about the development of the atomic bomb as some of the people I studied with were parts of the Manhattan Project.  You need to learn the importance of failure as well as hunches and the need to distrust your own work.  

 

The history of science, like the history of art or music,  is a story of the development of ideas that can be appreciated by non-specialists.   There are some wonderful books out there.  The trigger for this post was one of them:  Einstein's Fridge by Paul Sen.  I know the technical area well, but have big holes in my understanding of how all of this came about.  If you can follow articles in the New York Times science section, you'll learn a lot of what the physics is saying without the math and how it changed the world.  He gives a very simple, but accurate, description of entropy and has the best description of photosynthesis I've seen that doesn't get into biochemistry.  The historical motivations make it come alive.  I'm stealing some of his clear descriptions.

 

Most of this is probably true in many other fields.  About twenty years ago a friend invited me to dinner with Maurice Wilkes - his grand advisor.  Even though Maurice was in his late eighties the discussion went on late into the night and continued on two more occasions. I'm not a computer scientist or engineer, but Maurice is a physicist who happened to invent a good deal of the fundamentals of computing that's still in use.  Hearing him talk about the early history and the connections to our shared background made it all come alive.  The problems computers had to solve as well as the nuts and bolts of designing one - provided a wonderfully rich learning experience.  There was this hint of how the great mind of this humble person worked. A good history book can provide that kind of experience.

 

 

on fundamental change

 

Ludwig Boltzman, who spent much of his life studying statistical mechanics, died in 1906, by his own hand. Paul Ehrenfest, carrying on the work, died similarly in 1933. Now it is our turn to study statistical mechanics. Perhaps it will be wise to approach the subject cautiously.

It's not uncommon for a professor to quote the first paragraph of States of Matter by D.L. Goodstein on the first day of an undergrad statistical mechanics course.  Statistical mechanics is an outgrowth of the study of thermodynamics which had become a major intellectual effort attempting to understand heat engines in the 19^th century.  You can derive the results of thermodynamics from it and it led to much deeper explorations including the beginnings of quantum theory.  It's also concerned with entropy.    Entropy is at the heart of understanding change.  It's deep enough to be tightly connected with why time only goes forward and what cause and effect are.  Popular definitions aren't accurate. It isn't the tendency to disorder and it isn't the entropy computer scientists talk about (although Shannon's entropy is an exceptionally important tool for thinking about information). 

 

Unfortunately the fundamental concept of entropy is a bit abstract.  xkcd notes a problem common in science and undoubtedly many other places.  I'm frequently guilty, but I started to put together a post on the difference between entropy and complexity and why increasing entropy doesn't imply increasing complexity that doesn't involve math.  I found myself sketching pictures and wishing they were animated.  Then I remembered Sean Carroll did a series of very short YouTube videos with Henry Reich creating the animations as part of Henry's Minute Physics series.  They're wonderful!

 

The third video: Where does complexity come from?,  gets at the core of the entropy and complexity and why entropy isn't disorder.  It works as a stand-alone, but I recommend watching all five in order.  They achieve a good balance of getting the basic concepts across without any danger of anyone committing suicide.

 

Sean begins with why doesn't time go backwards and covers a fair deal of what the Second Law of Thermodynamics implies.  Things like cause and effect, the origin of complexity and even how life can exist.

 

Some deep and sexy physics without the math.