omenti

seemingly simple questions

 

what is a ruby and why is it red?
why is the friction so low on a sled?
on a plot of P versus T,
sketch out the phases of helium three.

 

Janos loved simply stated questions - and took delight if he could make them rhyme.  I had thirty minutes to answer.  The first question was straightforward although there are answers at several levels of depth.  The second turned out to be a trick question.  The folklore answer is the pressure of a blade on the ice, lowers the melting point of the ice and gives a very low friction watery surface.  I had skied, skated and fallen on the ice over the years, but I hadn't thought about what makes a surface slippery and hadn't questioned the explanation. 

 

I worked out how much added pressure would lower the melting point and made a simple calculation - what if a skater had a few square inches of contact area and weighed two hundred pounds - say one hundred pounds per square inch at the blade.  For this example the melting point drops less than a tenth of a degree F.  If the ice is below that temperature in the first place, skating wouldn't work.  This is something of a problem as I've skated, skied and fallen on much colder ice and snow.  

 

Janos smiled. 

 

At this point the problem becomes interesting.  With the simple model broken one has to propose new models or think about ways to make measurements that would add insight.  In an oral exam it would be foolish to propose a new model without offering a way to test it.  I remember concentrating on possible measurements.

 

This turns out this is a difficult problem.  The interface between two surfaces is largely hidden.  Progress has been made in the decades since and there are two leading theories.  Normal ice is a rigid hexagonal crystal structure of water molecules.  At the surface this structure breaks down as there aren't any water molecules on the other side of the top molecules to hold them in place.  The surface molecules form a semi-mobile liquid layer a few atoms thick.  A very slippery layer.  There are some problems with this as surfaces aren't very smooth at our scale  A second theory holds that friction provides some local melting that goes down a few atoms creating a slippery liquid surface.¹  

 

Two theories and an incomplete understanding even though the underlying physics is well understood.  There are a lot of interesting questions that haven't been worked out and this makes physics such an interesting sport.   In the meantime enjoy Winter sport on your own or watching the experts.  I'm a fan of Winter and its sport, but a warning for those that walk with me when ice is around.  I'm not particularly observant of ice and am generally uncoordinated.  This combination leads to falls.  Since I've broken my left arm four times and my right arm zero, it probably makes sense to stay to my right.

 

Another interesting "obvious" question presented itself a few years before when I was an undergrad.  The professor was famous for beautiful but deep simplicity.  He liked oral exams and often started out with simple but impossible thought experiments to lead a student.  It turned out this is how he played with ideas.  

 

Imagine that fusion turned off in the Sun.  Only that process shuts off - imagine that everything else stays intact.  What would be observed from Earth?

 

Clearly a trick question.  A similar question is sometimes posed in high school physics to get a student to consider the finite speed of light and the Sun's shape.  In the simple case a black dot appears at the center of the solar disk and spreads grows to the edge.  You can work out the rate if you like.

 

 

Far too easy and out of place - this was a quantum electrodynamics course.  It was also about the time Ray Davis raised some interesting questions about how the Sun worked.

 

Sorting out how the Sun works has been one of the triumphs of science.  During the industrial revolution the Sun was assumed to be a mass of something like a fossil fuel.  Calculations indicated a very brief life - tens of thousands of years.  This was in conflict with the geologic record.  Darwin originally thought the Earth to be a few hundred million years old based on some contemporary geology, but didn't publish as the results from physics indicated a much smaller time.  Physicists of the day didn't believe their calculations. They recognized there must be some unknown process at work, but at the time evidence was lacking.  Like dark matter and dark energy now, it was a known unknown candidate.

 

Many threads came together.  By the early 1800s physicists and chemists were using prisms to split light into a spectrum to identify molecules and atoms.  Some curious souls tried this on telescopes as film became sensitive enough to create a record. Using this process helium was discovered - on the Sun before it was found on Earth.  The industrial revolution had created a boom in physics to sort out thermodynamics and hopefully improve the efficiency of the machines of the day.  The understanding of thermodynamics, in turn, helped create the intellectual foundations of quantum mechanics.  Einstein showed the equivalence of mass and energy.  Bits and pieces of understanding came together and the process of fusion - slapping a couple of atoms together to form a new heavier atom and liberating some energy - made itself apparent.  The fundamental process of the Sun was beginning to emerge.

 

I often refer to fossil fuels as "nearly ideal." They are energy dense, easy to mine and process, inexpensive, easy to store and relatively safe.  There are some unfortunate byproducts, but they drove the industrial revolution and continue to drive the economies of the planet today.¹  Gasoline stores about one hundred times the energy per kilogram as the best rechargeable batteries.  Coal stores about half as much as gasoline, but there are almost in the noise compared with nuclear processes.  Specifically the energy from the mass difference when fusing hydrogen into helium has millions of times the energy density.  It takes place naturally in stars, but sadly is very difficult to achieve on Earth.²

 

So back to the question.  The process of solar fusion was almost completely worked out by the time I was a student.  The mechanism is a bit complex, but basically four protons come together in a few steps to form a helium nucleus and release energy.  Some of the excess energy is carried off by a neutrino and some off by very short wave light (gamma rays).³  The neutrinos don't interact strongly with matter and fly unimpeded through the Sun at nearly the speed of light.  They fly out in almost unimaginable numbers  At the Earth's distance there is a steady stream of about 70 billion per square centimeter per second.  While most  pass through the Earth as if nothing was there, a tiny fraction smash into things - things like solar neutrino detectors.  If nuclear fusion were to suddenly stop we'd notice the solar neutrino flux would drop to zero.  We'd see it about 500 seconds after fusion stopped - their time of flight to Earth.

 

Light is a bit trickier.  Fusion only takes place in the inner core of the Sun.  Gamma rays from the process bounce around as if they were in a huge spherical pinball machine.  Along the way they downshift in energy so much of the energy is radiated as visible light by the time it makes it to the Sun's surface.  My task was to estimate how long it takes for light energy to percolate out from the Sun's core to the surface where it could radiate to space.   I came up with about 30,000 years.  The best estimates are closer to 100,000 years, so this isn't bad for a quick back of the envelope. 

 

Science often proceeds like this.  One discovery building on another. It is often unclear exactly where the new ideas will come from and clever funding is something of a loaded dart game.  Some questions respond more rapidly than others, but patience is part of the game.

 

Technology is somewhat like this. Exact paths are frequently unpredictable and practical uses can wait for decades while other supporting technologies become available.⁴  Technology is fueled by basic research.  If you stop or slow basic research there  still see may be progress for a few decades, but there is a point where progress fades.  I fear the US and EU is currently in a partial retreat.

 

There is an additional complexity of mixing technology and sociology.  In retrospect the fading of importance of the desktop web and the rise of the smartphone and social apps becomes clear if you look at basic sociology and anthropology and the notion of the strength of social links.  The tech wasn't ready yet.  If basic understanding isn't there the result is often a Cambrian-like explosion of new companies followed by a near extinction of most of them.  Messy and unavoidable, but such is progress.  To skate to where the puck will be and make it through this mess one must understand the technology path and sociology.  Not an easy task.

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1 I'm very interesting in getting away from their grip!  Sadly they are so inexpensive, energy dense and easy to use and store that it is difficult finding substitutes.

² People have been working on fusion reactors since the 50s.  At first it was about 20 years off, but serious people tend to say it is at least 50 years off.  My guess it will be 50 years off for quite some time.  We can capture fusion energy from some future reactor or we can capture it from the Sun now.

Although the energy density from the mass difference in solar hydrogen fusion is tremendously high, the energy density in the core of the Sun isn't.  It turns out the process is very slow at the temperature and pressure at the Sun's core - something like 275 watts per cubic meter.  By comparison the metabolism of an average person is about 1450 watts per cubic meter - the Sun is closer to the metabolism of a lizard.  The trick is  a lot of hydrogen in the Sun, so it can burn for billions of years. 

³ a very high level explanation here

⁴ It was very clear in the 90s that something like a smartphone would be revolutionary, but one had to wait on Moore's law, battery electrophysics and billions of dollars of infrastructure spending before practical devices emerged.  I used my first touch screen in the late 80s and worked with a lab that focused on video gesture recognition at the same time.  

 

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Recipe corner

 

For whatever reason I was making chocolate chip cookies. I give most away for obvious reasons, but good ones are worth the effort.  Rather than give my favorite recipe(s) or get into the butter vs shortening wars, I'll offer a few tips that can improve any chocolate chip (or similar) 

 

° Use good ingredients!  Fresh high quality butter, sugar, flour, etc.  I use pasteurized eggs so I can safely sample the batter.  For vanilla use or make a good extract.  For chocolate I use chop up a 60 to 70% bar.  Usually Lindt.  If I can get them I use chocolate discs from Valrhona .. they melt much more and help make a very chewy cookie.

° Chocolate's flavor comes out with salt.  Fine grained sea salt - uniodized - is best.  At these temperatures the iodized salt imparts an unnecessary flavor.

° Cream the butter and sugar until the mixture is very smooth.  Over mixing isn't a problem.  Be careful with the eggs.  Don't over-mix when adding flour - over-mixing gives tough cookies.

° Chill the dough!!  Wrap the dough in plastic warp and refrigerate for at least 24 hours.  This allows the ingredients to combine and is a core secret used in most of the great cookies.  Plus you have a supply of chocolate chip cookie dough in the fridge.  Go ahead and have a bit if you've used pasteurized eggs:-)

° Use a heavy baking sheet or pan.  The thin ones warp and lack the mass to average out some of the temperature differences in your oven.  Stay away from dark metal.  I like to line with a non-stick baking mat.  Parchment paper is also good.

° Take the cookies out just before they are done enough for your tastes and let them cool on a rack to finish off the cooking.

 

moving heat

Our Winter has been impressive.  The ice on the local pond is nearly strong enough to support a person.  Yesterday an epic storm gave an excuse to enjoy the season.  I ended up getting very wet and cold, but for whatever reason you learn to love the Winter if you grow up in a place like Montana.  The season is a good time to sit back and read.  Last night as I tried to see if I could still remember a favorite poem by Robert W. Service, I remembered a great short story by Ambrose Bierce.¹

 

In 1933 the Tuscany tied up at a dock in Calcutta with a most unusual cargo.  Financed by Frederic Tudor, it was a dramatic proof of concept of an idea that seemed daft when originally proposed.

 

A few decades earlier Tudor had one of those consuming ideas.  He didn't have any experience in science or engineering, but he became fascinated by the New England practice of cutting pond and lake ice during the Winter and storing it for months in straw insulated underground ice houses. Often the ice would hold out as long as July and be sold at a profit.  He reasoned that ice could be insulted and put on fast boats to the Caribbean and sold to the landed gentry to chill their drinks.  Armed with an enthusiasm that others considered a lack of common sense, Tudor bought a brig and hired a crew to cut ice from a place near Walden Pond.  

 

The Favorite set sail on February 10, 1806 from Boston to Martinique with its cargo of frozen water insulated with straw.  Much of the ice survived the 1,500 mile journey, but he had neglected to build an insulated ice house on the receiving end and most of the cargo melted resulting in a big loss.

 

The papers caught wind of the loss and Tudor became a laughing stock.  The whole notion created cause for story telling.  Decades later Ambrose Bierce got into the act:

 

 

The Failure of Hope and Wandel

by Ambrose Bierce

 

From Mr. Jabez Hope, in Chicago, to Mr. Pike Wandel, of New Orleans, December 2, 1877.

 

I will not bore you, my dear fellow, with a narrative of my journey from New Orleans to this polar region. It is cold in Chicago, believe me, and the Southron who comes here, as I did, without a relay of noses and ears will have reason to regret his mistaken economy in arranging his outfit.

To business. Lake Michigan is frozen stiff. Fancy, O child of a torrid clime, a sheet of anybody's ice, three hundred miles long, forty broad, and six feet thick! It sounds like a lie, Pikey dear, but your partner in the firm of Hope & Wandel, Wholesale Boots and Shoes, New Orleans, is never known to fib. My plan is to collar that ice. Wind up the present business and send on the money at once. I'll put up a warehouse as big as the Capitol at Washington, store it full and ship to your orders as the Southern market may require. I can send it in planks for skating floors, in statuettes for the mantel, in shavings for juleps, or in solution for ice cream and general purposes. It is a big thing!

I inclose a thin slip as a sample. Did you ever see such charming ice?

From Mr. Pike Wandel, of New Orleans, to Mr. Jabez Hope, in Chicago, December 24, 1877.

Your letter was so abominably defaced by blotting and blurring that it was entirely illegible. It must have come all the way by water. By the aid of chemicals and photography, however, I have made it out. But you forgot to inclose the sample of ice.

I have sold off everything (at an alarming sacrifice, I am sorry to say) and inclose draft for net amount. Shall begin to spar for orders at once. I trust everything to you--but, I say, has anybody tried to grow ice in _this_ vicinity? There is Lake Ponchartrain, you know.

From Mr. Jabez Hope, in Chicago, to Mr. Pike Wandel, of New Orleans, February 27, 1878.

Wannie dear, it would do you good to see our new warehouse for the ice. Though made of boards, and run up rather hastily, it is as pretty as a picture, and cost a deal of money, though I pay no ground rent. It is about as big as the Capitol at Washington. Do you think it ought to have a steeple? I have it nearly filled--fifty men cutting and storing, day and night--awful cold work! By the way, the ice, which when I wrote you last was ten feet thick, is now thinner. But don't you worry; there is plenty.

Our warehouse is eight or ten miles out of town, so I am not much bothered by visitors, which is a relief. Such a giggling, sniggering lot you never saw!

It seems almost too absurdly incredible, Wannie, but do you know I believe this ice of ours gains in coldness as the warm weather comes on! I do, indeed, and you may mention the fact in the advertisements.

From Mr. Pike Wandel, of New Orleans, to Mr. Jabez Hope, in Chicago, March 7, 1878.

All goes well. I get hundreds of orders. We shall do a roaring trade as "The New Orleans and Chicago Semperfrigid Ice Company." But you have not told me whether the ice is fresh or salt. If it is fresh it won't do for cooking, and if it is salt it will spoil the mint juleps.

Is it as cold in the middle as the outside cuts are?

From Mr. Jebez Hope, from Chicago, to Mr. Pike Wandel, of New Orleans, April 3, 1878.

Navigation on the Lakes is now open, and ships are thick as ducks. I'm afloat, en route for Buffalo, with the assets of the New Orleans and Chicago Semperfrigid Ice Company in my vest pocket. We are busted out, my poor Pikey--we are to fortune and to fame unknown. Arrange a meeting of the creditors and don't attend.

Last night a schooner from Milwaukee was smashed into match-wood on an enormous mass of floating ice--the first berg ever seen in these waters. It is described by the survivors as being about as big as the Capital at Washington. One-half of that iceberg belongs to you, Pikey.

The melancholy fact is, I built our warehouse on an unfavorable site, about a mile out from the shore (on the ice, you understand), and when the thaw came--O my God, Wannie, it was the saddest thing you ever saw in all your life! You will be so glad to know I was not in it at the time.

What a ridiculous question you ask me. My poor partner, you don't seem to know very much about the ice business.

 

Most people would abandon the ice shipping business, but Tudor pushed ahead and secured a monopoly in Cuba and built an ice house in Havana.  The first trip to Cuba was still a loss, but close enough to success that he was encouraged.  He gave away ice samples in bars hoping to create a demand and tried again.  And again.  And again.  In six years he had lost enough to land in debtor's prison.  

 

A normal person might give up hope, but Tudor was learning with each failure.  He became something of an expert in practical thermodynamics and realized heat flows from warm to cold regions rather than the other way around and that he needed to be concerned with conduction and convection.  He worked out that sawdust was a much better insulator and that there was a need for cutting the ice smoothly so it could be packed tightly in the ship's hold. He began to turn a profit. 

 

By the time the Tuscany made it to Calcutta Tudor was a wealthy man. Shipping ice had become practical, but a disruptive invention appeared about the same time and was perfected enough in the next several decades to mostly eliminate seasonal ice storage and long distance shipments.  

 

Short distance shipments were still needed through the 1930s as businesses and people had ice boxes to chill their food. Refrigeration at the home scale began to become practical in the 20s and 30s.²  My mother remembered deliveries from the ice man during the depression when they could afford it but a home refrigerator was well beyond their means.  She knew she wanted one and it was a future she was counting on.  

 

Fortunately the family couldn't afford an early model as the units used toxic refrigerants.³  DuPont introduced Freon in the late 20s and over the next decade home refrigerators became much safer - at least within the home.

 

The development of refrigeration has a curious history if you are inclined to reading about emerging technologies.  A guy named Clarence Birdseye was another one of those curious people who made a dent in the way we live.  Mark Kurlansky's recent biography is a more than fun read.

 

Refrigeration is usually accomplished by removing heat from a refrigerant and then allowing what you need chilled to come in thermal contact with that material.  The process is inefficient takes a lot of energy.  A great way to heat a room is to open the door of your refrigerator and freezer.  A heat pump cools the outdoor air (or water) with the "waste" heat being used for heating.  For those that live in an area with the right climate it can be a very efficient way to heat a house.

 

There are a number of neat ways to cause extract heat from a substance.  There isn't time to do anything but list a few:  ultrasonic freezers have been investigated - Ben and Jerry's even toyed with the concept with Penn State, thermoelectric refrigeration has seen some use and you may have one to take beer and sandwiches to the game,  laser cooling is used to reach extremely low temperatures and magnetic refrigeration has been a holy grail for some for about 130 years.  It always impresses me how the fundamental understanding of many physical processes precedes even early engineering attempts by a long time.  Scientists and their funders often have no idea what a fundamental discovery might be good for and even those who make early practical implementations often miss how their invention will be used.

 

The other trigger for this post was a video from GE on their current prototype of a magnetic refrigerator.  In theory this could be more efficient and environmentally benign than the compressor based units in your house and car.  Traditionally this required an expensive rare earth, but people have been focusing on less expensive alloys...  Perhaps you'll buy one in twenty years.

 

 

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¹ Robert W Service wrote poems that are particularly attractive to Middle School age kids.  Jeri and I can both recite The Cremation of Sam McGee - the quintessential 7^th grade poetry experience in parts of Montana and a great read during the Winter.

² One of the first refrigerators came from Frigidaire in the late teens.  In 1922 a home model with nine cubic feet of space sold for about twice the price of a Model T Ford - perhaps half a good middle class income.  It was temperamental and required special plumbing for its water cooled compressor as well as the availability of electricity - something that was rather expensive at the time for an appliance that was always running and using a lot of power.  

³ Most of the early refrigerators used sulphur dioxide as the refrigerant and leaks caused blindness and skin burns.  The other major refrigerant was methyl formate, which was even worse.    

 

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Recipe Corner

 

It turns out much of the quality of ice cream is determined by the size of the ice crystals that form in it during freezing.  Large crystals form if the churn-freeze phase is slow - you want to quickly and uniformly move as much heat as possible from the ice cream mixture.  I find getting a freeze in ten minutes or less works out fairly well and it is useful if you "season" the newly churned batch in the coldest possible temperature.  Unfortunately setting your freezer to -10°F or colder can cause expensive mechanical failure (guess how I learned?  I shoot for -5° to 5°F these days in interest of avoiding $500 repair bills).

The best home results are probably obtained with a fairly spendy dedicated ice cream freezer, but nothing under $1,000 will beat a conventional salt and ice churn.  I recommend White Mountain, having gone through three lessor freezers over the years.  If you have kids a hand crank is fun, but if you don't I recommend a motor.  There is some fun instrumentation hacking you can get into if you are so inclined.

I was interested in great ice cream and can't afford a commercial blast freezer.  The trick is to use a lot of liquid nitrogen (you can use dry ice, which is easier to obtain and somewhat safer, but if you are crazy enough for that you might as well go all the way). To do so you'll need a supply of LN₂ and a dewar.  Advanced cooks are beginning to use dewars as LN₂ is useful for other food preparation, but we're talking exotica and you can seriously injure yourself if you aren't careful.  So I'll just say I've had excellent results mixing by hand as well as pouring the LN₂ into a Kitchenaide.  A "home" LN₂ ice cream freezer a great engineering class project or even a Kickstarter idea (hint, hint - Jan and Jeff).  I use thick rubber gloves, goggles and a heavy long sleeved shirt when making the stuff.  I used to be able to get access to a dewar and LN₂ where I worked, but that was a long time ago.  Now I need to borrow a dewar elsewhere and find liquid nitrogen at a welding supply.  I generally try to have about 4 or 5 liters of LN₂ on hand for a liter of ice cream.  The process is very mad scientist and impressive.  No more detail as you really need to know what you're doing to go this route, but the ice cream is amazing.

Currently I use an old dedicated Italian freezer - a very small compartment and an oversized refrigeration unit.  It does almost as well as a White Mountain churn.  Guests get to lick the dasher.

 

This is  a very simple and good french vanilla - a good starting point for experimentation.  Of those that use eggs I tend to prefer the non-custards .. eg - raw eggs are used.  This is ok if you can pasteurize your own eggs or find a source.  I used to do it myself, but now use Safest Choice.  These are also useful if you sample cookie dough:-)

 

Simple French Vanilla Ice Cream

 

Ingredients

 

° two large pasteurized eggs (eggs are probably fairly safe, but I strongly recommend pasteurized eggs for anything raw or undercooked)

° 400 g white cane sugar

° 2 cups whipping cream - try to stay away from ultra-pasteurized cream as the flavor isn't as good

° 1 cup whole milk - also stay away from ultra-pasteurized

° 2 tsp high quality vanilla extract (you can also scrape vanilla beans)

 

Technique

 

° whisk the eggs in a bowl until they are light and fluffy

° whisk in the sugar a bit at a time until completely mixed

° pour in the liquids and whisk to blend the mixture

° churn freeze to the manufacturer's instructions

 

 

a 1620 japan and a bicycle

During the last Winter Olympiad, almost exactly four years ago, a  friend was rewarded with a special bicycle.  Thinking about this and watching Sage Kotsenburg take the gold in Slopestyle triggered a few thoughts.

 

Colleen is one of those people who goes out and just does it. She was worried about climate change and the fact that many American kids are out of shape.  Both are enormous problems that require efforts at many levels and she saw encouraging children to learn how to garden and use their bicycles more as a project she could take on.  Trek, a large American bicycle maker, agreed and created a very special bike in recognition of her work.

 

It turns out the bike had to be special as Colleen happens to be unusually tall with much of it in her legs.  Tall enough that normal bikes don't allow a comfortable and efficient riding position.  Most of us can get a good fit by finding a frame size and geometry that is a reasonably close fit and then having a professional fiddle around and make everything perfect.  But a few people are better served with a made to measure frame.   The final result was a learning experience and was delivered with a beautiful paint scheme.¹

 

At the time Colleen had just retired from professional beach volleyball.  Up until then much of her life had been defined by sport.  Before the beach she was professional indoor player in Italy and the Netherlands and before that an All-American in college.  She grew up as one of those kids that you would chose first for your teams.  Athleticism, drive and the height for some sports.  A natural.

 

Sage Kotsenburg is a natural.  Perhaps and extreme natural.  It turns out he had never attempted the trick that took him to the top of the podium - 1620° of rotation with several complex moves along the way .. . the 1620 Japan.  No one else had attempted anything like this either.  It came to him three minutes before he pushed off on his run.  It also turns out he hadn't been in a gym since September.

 

Most of us can participate in sport at some level.  At many levels  of participation passion and practice - what might be called drive - often determine outcomes.  Many of us remember that 5'9  star on their high school basketball team.  But as the level of competition increases and athletes become more elite, drive alone no longer cuts it.  

 

A sport often selects not only a specific body type, but also muscle type, the ability to process oxygen, reaction time, vision, and even the ability to visualize.²  Body type is easy to pick out short track speed skaters tend to be short with low centers of gravity and exceptionally low amounts of body fat.  Elite gymnasts and divers are compact - physics dictates this as it is difficult to accelerate long limbs.  Cycling road racers are mostly between 5'8 and 5'11, swimmers have long torsos and short legs, basketball players are remarkably tall, and Sumo wrestlers are not exactly thin.

 

Some, but not all of the positions, in indoor volleyball favor height.  Jumping ability, vision and "court sense" are also important and Colleen had those so volleyball was a natural sport.  Beach volleyball, on the other hand,  only has two players and is not quite as specialized.  Height is still extremely useful, but so is acceleration and Colleen's limbs are too long to accelerate quickly.  She worked on improving as much as she could, but physics gets in the way.  The trick was to find a lightning fast partner.  But it is also important that both players have the other gifts required for the sport, so the search was difficult.

 

David Epstein's The Sports Gene: Inside the Science of Extraordinary Athletic Performance is, in my opinion, the best science book of 2012.³  It focuses on elite athletes with some of the best non-technical explanation on why most of the best long distance runners are from a small part of Kenya and most of the best sprinters are from a small area of Jamaica.   There is insight on the dramatic increase in female athletic performance, why 10,000 hours of training is bunk as there is a genetic component to how we respond to various types of training.   There is even the story of a true super-baby.  

 

Epstein has an easy, almost conversational, style and I'd recommend his book to anyone with an interest in sport, to anyone with a kid who does sports, and to anyone interested in a readable "it's not as simple as nature vs nurture" science book for non-specialists.  A perfect companion book for the Olympics - the story on XC skiing will completely amaze you.

 

That's one book...

 

Colleen's physical appearance makes her fascinating to kids. Combine this with her work as a professional athlete and she reasoned she might be able to inspire some to bike to school and to work in a community garden.  She geared up and set to work.  Work that was much more difficult than first imagined.

 

There was a fly in the ointment.   Parents objected to such "dangerous" activities.

 

People are terrible as assessing risk.  The notion of risk has been blown out of proportion.   Sadly the American response is one of fear and this is amplified when children are involved.

 

Teens exhibit dramatically different online behavior from adults  Some have labeled them digital natives - implying they have a very different relationship with technology and communication itself.  That they are somehow different and many other things follow from that. 

 

The general public's use of the Internet dates to the mid 90s.  About that time my Human Computer Interface department began to study networked behavior in teens and twenty somethings.  Some of us were studying usage data and others were conducting ethnographic studies.  It was noted teens weren't naturally adroit at understanding the new technologies.  They could use some of the technologies, often finding uses not envisioned by the creators, but an understanding of the technology was rare.  One described teens, in fact most non-technical users of technologies, as technology idiot savants. 

 

It's Complicated: the Social Lives of Networked Teens by danah boyd is my second recommendation.⁴  danah is a social researcher who has been interested in teens and their use of the Internet for well over a decade.  She's done a large number of interviews carefully asking questions and listening as a proper ethnographer does.  And she asks good questions, thinks and then continues to listen at a deeper level.

 

Her book tackles a very complex subject.   Teens and adults are both human and, as such, desire social contact.  Adults have an easier time finding high quality contact, but teens are experimenting and learning and are effective limited by adults and social constructs.  There is a huge perception gap between the two groups.  Contrary to popular opinion teens strongly prefer real face to face interaction, but opportunities are vastly reduced from what they were a generation ago.  To get some social contact they are forced to knit together online interactions using available tools - often in ways and for purposes different from what the tool inventors and service providers envisioned.  

 

Privacy is important, but takes on different meanings.  Teens employ many novel approaches with varying degrees of success.  There is a deep misunderstanding on the part of adults.  The same extends to online safety and the adult natural fear and over-protective nature feed the problem.  Conversational context is a deep issue that adults frequently don't consider.

 

As many of you know I have issues with some popular terms.  One is digital native and I agree with danah's position.  The term is so general as to be non-descriptive and, out of context, overly confusing.⁵

 

danah has a nice chapter on bullying and the asymmetry between teen and adult use of the term.  Her definition for bullying is, I think, particularly useful - particularly when one considers online behavior.  And speaking of useful, a regular reader of this blog will see her book on dealing with bullying published shortly.⁶

 

In summary It's Complicated is an enjoyable and an important book for anyone with teens, soon to be teens, and anyone who involved in networked services and applications - building, growing or investing.  I'd love to hear the reactions of teenagers.  danah's style is very readable for such a technical subject and I can hear her voice as I read it.  She manages to get across the notion of what a public is as cleanly as I've seen it done without getting into the weeds.  

 

And no - I'm not very optimistic on seeing any growth in teenage use of Facebook.  The story of Myspace to Facebook is fascinating and has some fascinating roots in race, social class and design.  There are some interesting echoes in the design of Microsoft, Google and Apple products.

 

So much more, but this is a deep and complex subject and going further than a brief bit of bait is inappropriate unless I was to write a few chapters.  I'd probably do that, but I'm not a good writer and danah is deep -  you need to read it.  

 

You could do far worse than to read both of the books. Both were good enough that I read them front to cover in a single session.  Not good for sleep, but there are times when you ujust can't put a book down.

 

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¹ Most bike geometries are made for a range of male proportions, but many can be adjusted for female riders.  In the past decade women's specific designs have appeared that can give better fits and a much more comfortable ride.  Colleen's height puts her past the normal range for most men's bikes, plus her proportions dictate a different geometry.   The photo shows her on a production bike where an attempt has been made to get a fit - approximately wrong.  In the end the final result of the Trek exercise is in the range of a 70 cm steel frame.

Made to measure frames are easier to find these days as there are a number of excellent small bike makers in the US.  Many of them use the same CAD tool that helps dictate geometry.  If you are a woman and need a custom frame it is best to seek out someone who understands the somewhat different requirements.  In this case some completely new design was required. 

Stay away from mail order and big box stores if you are looking for a bike.  The best best, even for a very garden variety ride, is to consult with someone who can listen to your needs and, combined with your measurements, find something that you'll be happy with.  The good shops tend to be bicycle-only.  The great ones will send you elsewhere if the right bike is one they don't happen to carry.

² I haven't seen a competitive sport that requires smell and taste ...  perhaps a challenge for someone.

³ I won't give a direct link.  Most of the books I buy these days are ebooks.  The default for most people is Amazon, but I prefer the readability and layout of Apple's iBook reader.  Prices differ on the various stores.  The Sports Gene goes for the same at both stores, but the next book I note is significantly less expensive from Apple.

⁴ I have an early copy - it should be out by the end of February.  danah spells her name without capitals.  

⁵ I'm neither techno-utopian or techno-dystopian.  The term digital native was used by techno-optimists in the 90s to paint a paritcular future that was something of a belief and hasn't panned out.   It may have some utility in certain contexts, but it don't work for general use.  I remember talking with danah on the subject ten years ago when we were chatting about overloaded language and the Internet.  Both of us are in the techno-realist camp ...  go out into the wild, look and measure first.

I worry the phase space for dystopias is much larger than that for utopias and hope we can move the realistic world more towards the utopia space.  That demands an enormous amount of thought and effort.  Even a good enough path does not emerge on its own accord.

⁶ I only know a working title which I think is Don't Let the Bullies Ruin Your Life by Uche Nnoka.  I've seen a very early draft and it looks useful.  Her definition of bullying strikes me as aligned with danah's.

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Recipe Corner

 

 

A nice tofu soup that is perfect for a cold Winter day and just seems healthy

 

Tofu Soup

 

Ingredients

 

° 1 tbl good quality olive oil

° 1 medium onion sliced thinly

° 3 celery stalks sliced thinly

° 6 to 8 garlic clove sliced thinly

° 2 tbl granted ginger 

° 1/2 to 3/4 tsp finely ground white pepper (white is important here!)

° 1-1/2 cup mushrooms

° 8 oz firm or extra firm tofu, sliced in thin slabs ...  get the good stuff at an Asian market

° 2 tsp sea salt

°  scallions chopped for garnish.  watermelon radish is great and I've microwaved frozen peas and used them with good success

 

Technique

 

° put the oil in a pot over medium heat and sauté onion, celery, carrots, garlic, and ginger 'til they are soft.  don't let them brown.  You may need a bit of water if the veggies aren't very wet and dry out in the process

° stir in the white pepper and about 10 cups of water, bring to a simmer and let it perk away for about 15 minutes

° add the mushrooms, tofu and salt and continue to simmer for another five minutes or so

° adjust with salt if needed

° serve in bowls with the toppings (scallions and some watermelon radishes or whatever) and drizzle with a bit of olive oil

 

 

 

 

 

the isthmus of data science

We finally had a break in the weather and I was able to spend a lot of time in the woods yesterday.  The Sun angle was noticeably higher and the snowy landscape was criss-crossed the the tracks of at least a dozen different kinds of animals.  The bonus that made it more than worthwhile was seeing our local coywolf.  I hadn't seen her in a month and was worried, but she looked great. Soon the sap would start flowing in the maples.   The Winter has been harsh of late but there was finally a sense of a stirring.  Tolkien had it right for climates like this - spring, summer, autumn, fading, winter, stirring - six seasons.¹  

 

Today is a cross-quarter day - the halfway point between the Winter Solstice and the Spring Equinox.  When people were more connected with the seasons a variety of  celebrations marked the day.  I'm mostly of Irish descent where the day is Imbloc or Brighid's Day - a stirring, but often an unsettled one.

 

Unsettled.  As I write it is still snowing after having put down eight inches.  The rest of the week promises no relief.  Of course the climate denier crowd is crowing about this disproving global warming, but much of the West Coast, Alaska and a large piece of Russia is amazingly warm.   Weather is not climate and one must look for trends.  The always marvelous xkcd said it well a few days ago.

 

To understand climate change you need to take lot of measurements over a long period of time around the world and perform extremely careful (and clever!) analysis.   People engaged in the research have to worry about errors at every step of the process and results are stated with conservative confidence levels.  Checks come from other groups studying the same phenomena using approaches that may be similar or different, but in the end Nature has the final say.   Such is science.

 

Scientists, particularly those in the physical sciences, are well versed in statistics and have developed many, perhaps most, of the analytical techniques.  New techniques have come as the scale of the task has increased along with visualization tools to understand and communicate the results.   It might be tempting to call this data science, but it isn't.

 

When I joined Bell Labs in the early 80s I went to more than a few seminars outside my field of study.  A lot was going on, it was Bell Labs during the glory years after all, but it was particularly interesting to watch the development of new machine learning techniques for pattern recognition and classification.  Some of them were far removed from statistics and others had bits and snatches.  Horror of horrors, error propagation was largely ignored and even impossible in some cases.  There was often a black box of sorts that required some tuning or training in order for these algorithms to work properly.  Voice recognition,  patterns in phone records, sound compression and many other tasks.  I got over the initial ugliness and soon found myself joining in - types of cluster analysis - in a project to detect and classify defects in integrated circuit photomasks and later trying to understand the underpinning of the AT&T call recording system.  

 

A brilliant feature of Research at AT&T was a focus on tool making.  John Chambers' department came up with a statistics language called S that later became New S and was  integrated with Unix.  It bristled with statistical techniques along with the emerging non-statistical techniques that were the domain of computer science and became a playground for exploratory and formal analysis.  In the end it became the basis for R - a great open source tool from outside the Labs.  

 

R revolutionized the sport and came at the right time as large amount of Internet data were becoming available inside and outside corporate firewalls.  One of its beauties was people began to attach the R analysis source with results in papers and a new generation came to speed.

 

Now the term data science is popular.  I'm not keen on the term as it certainly isn't a science.  For me it represents an emerging category of analysts who do not specialize in the statistical analysis of the physical sciences or the black box classifications from computer science, but rather have some competence in both areas.

 

A few weeks ago I was asked to give a talk to students taking an intro to data science course at a local university.   I'm afraid I tend not to make view graphs and winged it at the white board.  Sorry for the terseness but in the interest of time I'll attach part of a letter I sent to a friend with a mutual interest in the subject.  This is properly a very lengthy subject.

 

My goal was to give a flavor of what I think data scientist means these days and its historical roots as well as a few examples of approaches.  I didn’t have time to get to some fun ones.

- Data science is a hybrid of statistics and CS.

-  terminology differences can be very confusing ..  “model" as an example

- the statistical approach is for people who work in uncertainty.  confidence levels and extreme confidence in data, metadata and analytical techniques are paramount.  Science wouldn’t work without  this approach and it is my bias, but I sometimes walk on the other side

- CS folks are into things like classification and machine learning.  Confidence levels are often undefined and sometimes data quality isn’t optimal (but that can get you into trouble).  Yahoo, Google, Facebook, Twitter, etc all lean in this direction. It is the basis for many production systems at scale.  

- in theory a data scientist has an understanding of both sides, but in practice are mostly on the ML/CS side these days .. at least in the business world

- there is a lot of hype that comes from misunderstanding.  DS, like CS, isn’t a science.  DS is more of a craft and usually demands a combination of skills

° no one person has all of these skills, so there is usually a team.  Lone wolf DSs usually have a few extremely strong areas and consult with existing groups

°My list of necessary skills:

statistics, machine learning, math (at an engineering level - not math major math), data-viz, domain expertise … also there should be communication and people skills

domain expertise is critical as we will see, also communication/people skills:  these two have caused the majority of failures I’ve seen

- the importance of data quality, I have never seen a data set that didn’t require munging.   Simple things like time stamps can be very difficult

- scaling can be and is a huge issue.  Hadoop, etc are useful but way overhyped.  We are at fundamental limits with the statistical approach, but confidence in science driven requirements will force invention.  It always has.  (the synoptic telescope for example)

- some notes on data - there is bias in the data and the analysis,  quantify it if you can (statistical approach), learn to live with it.    Complete data sets aren’t complete!!!  not even close!

- EDA:  exploratory data analysis. the S language and now R and extensions to python.

- a few examples of common algorithms (you have to know a lot and have the taste to know when/where to use them!):

 

linear regression (long discussion..  lots of blank states as if they’d never seen it)  core to the statistical/scientific approach

k- NN (k nearest neighbors) - simple machine learning classification.  The concept of distance. Why it is easier than statistical techniques for classification. The art of training and tuning.   The need to get good enough

k-means - unsupervised machine learning …  convergence and interpretation can be major issues

 

° underscore that ML is a black box with tuning approach whereas statistical approaches demand knowing what is going on during the analysis.  They serve very  different needs.


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that’s as far as I got and I took up well over an hour.  I really wanted to talk about Bayes theorem as so many ML guys worship it (it is useful for certain classes of problems and inappropriate for many others)

 

I've glossed over a lot of important points and I'll be happy to go into detail.  I should stress data-viz can be very dangerous as it is very easy to paint a seductive story.  I've seen terrible failures in organizations without domain expertise built into the analysis group and in a lack of communication between the analysts and their customers.  There is a real danger of using prepackaged easy-to-use systems that give beautiful results.  While there is a lot of power under the hood you can end up in a ditch if you lack the experience.  

 

The CS machine learning techniques usually don't have statistical underpinnings, but are good enough for quick production work and can scale (although there are some great research issues on going further).  The statistical approach used in science has some very serious scaling issues that need to be solved.  I expect see solutions emerge from the huge scientific data hoses like Large Synoptic Survey Telescope and the mind wobbling Square Kilometer Array.²

 

In short data science is a bridge - an isthmus - between the large continents of physical science statistics and more black boxish techniques from  computer science.  It is still emerging and represents a combination of skills that will be found in no one person.  There is a lot of art to it and, at least the business focus, tends to work on problems where careful attention to confidence levels is less important than getting a good enough result and evolving along with the problems at hand.   But in the end there is a similar requirement to that of the physical sciences - you do need to understand your datasets and you need to ask the right questions.

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¹ In The Lord of the Rings the Elven calendar had six months.  There is a theme of sixes and twelves among the elves, but six seasons seems appropriate for the climate in Northeastern US.   I grew up in Montana where three might be more appropriate.  

² Very important tools that will drive analysis infrastructure and invention.  They deserve another post.

 

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Recipe Corner

 

I've been on a sweet potato kick lately.  This is a modification of an old recipe I've had for a long time.

 

Sweet Potato Stew

 

Ingredients

 

° 1 tbl olive oil

° 1 medium yellow onion

° 2 cloves of garlic, minced

° 1 tsp grated ginger (note - peeling ginger with the edge of a spoon is so much easier than using a knife!)

° 1/2 tsp cumin

° 1/2 tsp cinnamon

° 1/2 tsp red pepper flakes (or some other way to simulate a small bit of heat)

° 2 medium sweet potatoes, peeled and cut into inchish chunks

° 1 cup vegetable stock

° a half can of San Marzano tomatoes crushed (about 14 oz)

° 1 19 oz can kidney beans

° 1/4 cup smooth peanut butter

 

Technique

 

° heat oil in a large pan over medium heat.  Sauté onion 'til soft (don't brown)

° add ginger, garlic and spices and sauté 'til ou can smell them .. less than a minute!

° add veggie stock and tomatoes and sweet potatoes.  Cover, cut heat to medium-low and simmer for about a half an hour 'til sweet potatoes are soft

° add kidney beans and heat. Finally stir in the peanut butter and serve.

 

pete - a life that made a difference

The past half year has been a period of loss in my life.  These periods happen, of course, but it has been particularly concentrated and has forced a lot of thinking.  During one point last December a close friend called to see how I was doing and after listening for a few minutes she started to sing a familiar song that moved me from the shock I was experiencing to a point where I could finally cry:

 

To everything turn turn turn there is a season turn turn turn 
And a time to every purpose under heaven 
A time to be born a time to die, a time to plant, a time to reap 
A time to kill, a time to heal, a time to laugh, a time to weep 

To everything turn turn turn there is a season turn turn turn 
And a time for every purpose under heaven 
A time to build up a time to break down, a time to dance, a time to mourn 
A time to cast away stones, a time to gather stones together 

To everything turn turn turn there is a season turn turn turn 
And a time to every purpose under heaven 
A time of love, a time of hate, a time of war a time of peace 
A time you may embrace, a time to refrain from embracing 

To everything turn turn turn there is a season turn turn turn 
And a time for every purpose under heaven 
A time to gain, a time to lose, a time to rend, a time to sew 
A time of love, a time of hate, a time of peace, I swear it's not too late 

To everything turn turn turn there is a season turn turn turn
And a time to every purpose under heaven 
To everything turn turn turn there is a season turn turn turn
And a time for every purpose under heaven

                                                                 Pete's words adapted from Ecclesiastes

 

Pete Seeger was one of those remarkable people who saw injustice and through force of will managed to find a way to bring change.  He fought with words and music - words and music that inspired others.   Enough that a difference was made.

 

I never really met him.  I did see him at a few concerts and was able to shake his hand a few times, but that's it.  On the other hand he was one of the people who helped me find my moral compass.  He is one of the forces that helped make me as a person.

 

Rather than write a post today I'll link to something much better - a video biography that appeared on the American Masters series and was shown on Public Broadcasting.  

It is fascinating how important music and poetry were. Such a powerful form of participatory story telling.

 

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 Recipe Corner

 

Ben Cohen wrote a lovely remembrance and offered an image.  It reminded me of the first time I saw Pete live.  It was a small outdoor concert on a beach in Southern California with a few hundred people gathered around a large fire on a chilly January evening.  When I finally shook his hand, he made a comment on the excellent hot chocolate and offered it was good lubricant for conversation.  

 

Last night I made some hot chocolate and had it with stroopwafels.  The trick is to place the stroopwafel on top of the mug and let it steam for a minute or two.  There are so many ways to prepare hot chocolate, but this is one that works in the Winter.

 

Hot Chocolate

 

Ingredients

 

° 2 cups whole milk

° 1 tbl white cane sugar

° 1/2 cinnamon stick

° 1/4 vanilla bean scraped. This is roughly the equivalent of 1 tsp of a good vanilla extract if you don't have fresh vanilla beans

° 100g bar of 70% dark chocolate.  I usually use a Lindt 70% bar (3.5 oz)

° 1/8 tsp Ancho chili powder (a double pinch:-)

° pinch of salt

 

Technique

 

° Add everything but the chocolate, salt and chili powder to a medium sized sauce pan over low heat. Warm to a light simmer and remove from the heat for about ten minutes.  Remove the vanilla husk and the cinnamon stick.

° make a homemade double boiler and melt the chocolate over simmering water.  Better yet, use a bain-marie ...  recommended if you make hot chocolate on a regular basis.

° put the milk mixture over low heat and whisk in the melted chocolate

° add the salt and chili powder and serve in two mugs.