omenti

moving our personal atoms around - 2

Recently several studies have come out comparing how green electric cars are vs hybrids and conventional vehicles.  The conclusions are usually mixed, largely depending on how local electricity is generated - electrics do very well in places like Idaho, where most electricity is hydroelectric and poorly in North Dakota, which relies on coal.¹  

 

Real life is much more complex and sorting out life cycle emissions, energy mining emissions (difficult petroleum sources like tar sands are becoming increasingly important), and so on are extremely difficult to project so most examples tend to be special cases that may not be very close to your situation.  What is communicated is a sound-bite .. like "hybrids are greener than plug-in electrics" ..  even though that is not generally true. 

 

It turns out these comparisons are not only misleading, but aren't getting at the right questions.

 

clip once meant to run or fly swiftly.  This became applied to clippers - the fast sailing ships that began to dominate the long range routes in the 1840s.  For a few decades they ruled the seas.  Steam power was a competing technology, well proven in stationary and rail applications, but problematic on the sea due to (early on) low efficiencies of the engine and a poor understanding of propellers.  Steam was used for some ships, but its use on clippers began as a powered winch to raise and lower the sails.  

 

It turns out things changed - steam engines became efficient, propeller design advanced and not having to depend on the wind was a feature.  People starting rethinking what a ship was and what it was supposed to do.

 

Electric cars have been around for well over a century, but have been hampered by the poor energy storage capabilities of batteries compared to fossil fuels.  The advent of laptop computers pushed lithium-ion battery technology and made electrics sort of practical for some applications.  While there is the promise of dramatic improvements it is reasonable to sort out what a car is and what it means to move us around.

 

It is very easy to get lost in a thicket of calculations.  When I was looking at the efficiency of Colleen on her bicycle we started to talk about what it means to move a person around.  She weighs about 170 pounds and her bike comes in around 30.  An interesting metric is the ratio of her weight and the bike's weight and her weight.  In this case it is (170 +30)/170 or about 1.18.   Using this she can get the equivalent of about 1,000 mpg of "gasoline".

 

She has an old pickup that weighs about 4,000 pounds with her and a few gallons of gasoline.  Looking at our total load to payload ratio we now get 4,0000/170 ... about 23.5.  Colleen on her bike wastes much less energy as the combination is focused on carrying her around rather than the truck.  Her bike is a good match for her weight.  Her truck is an ok match for its weight - but why carry all of that around?

 

That which I am writing about so tediously, may be obvious to someone whose mind is less decrepit.

 - Ludwig Wittgenstein Remarks on Colour (295)

 

At the time I was writing a series of notes and giving some talks on energy.  They were aimed at a general audience, but weren't connecting - my writing isn't exactly good.  There were too many technical issues that needed explanation - or so I thought.  Colleen was helping me with comments and came up with some simple ways of looking at the issues.  Here is a simple, but accurate enough way of looking at things:²

 

° a car is about 25% efficient (best case) ..  when you burn a gallon of gasoline, about a quart is used to move you and the car around.  The rest is mostly waste heat.

° a car weighs about 25 times more than an average person .. of the quart used to move you and the car around, something like an ounce is used to move you.

° a single passenger car is only about 1% efficient

 

now for the electric car

 

° about 80% of the energy stored in the car's battery is used to move the car - something like three times better than a gasoline powered car

° the weight of the car isn't that different from a gasoline powered car.

° a single passenger electric car is about 3% efficient

 

A good case for car pooling!  But also for making lighter vehicles.  It vehicle efficiency in urban and most suburban driving is stop and go - the cost of accelerating a vehicle depends on its mass.  A light car is going to be much better than a heavy one.  Very small, but safe, urban cars have been built at well under 1,000 pounds.  Now imagine Colleen in a car that weighs 1,000 pounds with her.   If it is electric 80 cents of her energy dollar goes into moving her and the car around.  Multiply this by her weight over the total weight moved (.17) and you get something that is over 13 times as "efficient" as the single passenger gasoline powered car.  A remarkable improvement.³ And if she used a 50 pound electric bike the number would be 0.8 * (170/220) - over 62 times as good as the single passenger car!

 

The point is electric cars, by virtue of their electric motors, are more than three times as efficient as a similar gasoline powered car.  That number is likely to improve slightly.  The poor energy density of batteries and their high cost makes electric cars mostly impractical.  

 

Bikes are incredibly efficient as are ebikes.  Very small cars are very efficient.  A shift to bicycles and small vehicles may require a different infrastructure.  Bikes need bike paths, places to park and relative safety.  Communities in Denmark and the Netherlands are showing an efficient and inexpensive transport mode for short distances (up to about 10 km).

 

Crystal balls are usually faulty, but perhaps conventional electrified cars are the steam powered winches on the old clipper ships.  The ground transportation that will evolve will almost undoubtedly electrified, but highly computerized and part of a new infrastructure that may even impact urban and suburban planning as the gasoline car mostly created the suburbs.

 

At the same time other technologies are developing.  Vehicle sharing (car and bike) schemes are growing, car to car communications, sensor equipped roadways, autonomous vehicles, electric cars, using car batteries for grid storage.  Even how the cars (or whatever they will be called) are manufactured will become a big issue that will see enormous change.

 

These other technologies are developing both with and independent of the other technologies. They will stitch together producing something new and perhaps unimagined.  It is likely these paths will be different around the world.  At some point "good enough" states will form and become difficult to dislodge - just as the state of transportation that developed in the decade after WWII became very rigid in the US.

 

It is fun to speculate on scenarios, but assigning likelihoods is a very non-trivial task.  The only thing I feel very comfortable about is small, light, electric and autonomous or at least semiautonomous seem very likely in the next three decades.

 

So much will change.

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¹ a not entirely up to date listing from EPA's eGRID (pdf) 

² lots of footnotes are implied here, but reasonably good for the argument

³ This isn't a true efficiency, but rather a figure of merit for comparing types of transport.

 

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recipe corner

 

Sometimes you need a proper ice cream sandwich.  I don't eat many, but they are fun to give away. First you need to find or make a good vanilla ice cream.  Then the cookie.

 I usually make a chocolate chip, but gingersnaps work well - the cookies aren't that big in diameter, so the sandwiches aren't huge 600 calorie monsters.  Gingersnaps are good warm, but I like refrigerating them for ice cream sandwiches - add the ice cream and freeze the sandwiches. 

 

Gingersnaps

 

Ingredients

 

° 280g all purpose flour

° 1-1/2 tsp baking soda

° 1/2 tsp non-iodized salt 

° 2 tsp ground cinnamon

° 1-1/2 tsp ground ginger

° 1/2 tsp finely ground fresh black pepper

° 150 g unsalted butter softened to room temperature (you can used salted, but leave out the salt above)

° 130 g white cane sugar

° 1/2 tsp vanilla extract (I soak beans in rum for months)

° 80 g light molasses 

° 1 large egg at room temperature - I use pasteurized eggs so I can taste the dough and play with the flavor a bit using this recipe as a guide, but modifying

 

Technique 

 

° pre-heat your oven to 350°F , rack in the middle

° mix the dry stuff before the butter in a large enough bowl

° in a separate big enough bowl beat in the butter until fluffy and add the sugar, beating until it is smooth.  Stir in the egg, vanilla and molasses

° add the dry ingredients slowly and beat until smooth

°  roll into logs and wrap tightly in plastic wrap and freeze for a few hours until they are firm.  You can also refrigerate overnight.

° slice into rounds about 3/8" thick and bake until brown - about ten to twelve minutes for me. Optionally sprinkle one side with some sugar - if you can find big sugar crystals, extra points.

° let them cool on a rack

a cloaking device

In a vacuum the speed of light is exactly 299,792,458 meters per second.  It is also constant in a vacuum so it can be used as a length - stars are multiple light years away, the moon is about one and a quarter light seconds out, and if you're six feet tall it takes light about six billionths of a second to travel your length.¹  It travels more slowly when moving through matter, but for most materials the speed is also constant if somewhat lower.   

 

Jheri wrote and asked for a simple explanation of some recent physics that was interesting, but didn't require a deep physics background.  So this one is for Jheri - let's build something that may seem impossible on first blush and let's only use the fact that the speed of light is constant.  Let's build a cloaking device.

 

In the past year or so there have been a number of exotic schemes that use nano materials to make temporal cloaking devices.  Some have been built, but explaining them without some serious physics is very difficult.  But it turns out you can build a cloaking device with mirrors and it is easy to explain.  The only physics you have to worry about is that light travels at a constant speed.  You'll need four very flat mirrors and four special mirrors than can quickly change from being a mirror to a transparent window.  You'll need a light source, an object to illuminate and something to view the scene with - your eye or a camera for example.

 

There are a few impractical issues, but we're just after the basic physics.  Physicists go into a play mode with an idealized apparatus that only occurs in thought and is usually called a gedanken experiment (gedanke is German for thought).  

 

Here is a sketch of the apparatus we'll be using.²  

 

 

The mirrors A, D, E and H are very flat and can be quickly switched from being a mirror to a transparent pane.  Mirrors B, C, F and G are just very flat normal mirrors.  The odd shape in the center is an object that will be cloaked - perhaps a very valuable diamond.  

 

If the switching mirrors were set to transparent light would travel from the light source on the left through A and D, illuminating the diamond and then passing through E and H to the observer.   Just what an unwitting observer might expect...

 

but we'll be a bit more clever.

 

The mirrors are set at 45° angles and the path length for A, B, C and D is the same as that of E, F, G and H. 

 

We'll consider two interesting paths.  

 

path I  Mirrors A and D are set to transparent and E and H are set to mirror  The light path from the source to the observer is A, D, diamond, E, F, G, H.  It is longer than the simple "straight through" path where all of the switching mirrors are transparent, but the observer doesn't know.

path II  Now switch A and D to mirror and E and H to transparent.  The path is now A, B, C, D, diamond, E, H.  The path length is exactly the same as that of path I and the observer can't distinguish between the two.

 

OK - now for some fun.  I recommend pencil and paper at this point so you can sketch out what is happening.

 

Start with the apparatus set up as path I.  Now let's start the cloak.

 

° switch mirror A to its reflective state.  As this is a gedanken experiment it happens instantly.  A bit of light is traveling from A towards D, but the light immediately after the switch is now traveling towards B.  

° when the little bit of light traveling towards D has gone through D, switch it to its reflective state

you have now created a gap equal to the time it takes light to go on path ABCD minus the time it would take to directly go from A to D.  As time advances a segment of light is traveling from D to the diamond, but it suddenly stops - the light that should have followed it is on the ABCD circuit.  

When the gap reaches the diamond you have the duration ABCD-AD to do something with the diamond in total darkness (no light would make it to the observer) - for example you could remove it.  If the path ABCD was long - say AD was very short compared to ABCD, but AB was very long (put mirrors B and C on the moon for example) - you would have a long window to work with.

° Light continues to move along the ABCD path and as it leaves D and illuminates the diamond (or where the diamond was:-), the cloaking period has ended.  Now E and H are set to their transparent state.

° The light passes through E and H and then to the observer. From the observer's point of view there is always light - we've just played with its path.

 

Now imagine putting a clock in place of the diamond.  Let's say the ABCD-AD light path time is very long - five minutes.  If you were watching the cloak and started the cloak at 5:00 PM the clock would suddenly jump from 5:00 PM to 5:05 for the observer.  If you want to get fancy, think about how you might reset the device as a more challenging case.³   (update - August 15 ...  Jheri solved the reset case and posted her solution as a comment.  Don't look at the comments if you want the challenge.) 

 

Simple in concept, but it pays to draw the light paths for each of the steps to sort out what is going on.  And, although this is a gedanken experiment, there are very fast switching mirrors and you can perform the experiment in the real world.  There are some tricks to match intensities as mirrors aren't perfect and switching mirrors double so, but these are do-able details ...  at least on a small scale.

 

 

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¹ The meter is defined as 1/299792458 of a light second in a vacuum, so with refined measurements of the speed of light we get the meter to better precision too. 

Colleen is very tall at 2.00 meters.  People constantly are asking for her height, so for variety she can tell them she's six and two thirds of a nanosecond tall ...  at least in a vacuum or in our atmosphere...

² Based on an idea from Miguel Lerma.  Very elegant.  The physics existed to have worked this out over 110 years ago, but no one thought about cloaking devices using mirrors until recently.

 ³ hint: you have to combine two beams for awhile... this means you need some way to deal with the intensity change and possible interference if you use a laser.

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Recipe Corner

 

This is based on a recipe by David Lebovitz.  I had to make a vegan ice cream and it was great.  For extra richness you could replace 1/2 cup or thereabouts of coconut milk with heavy cream.

 

Vegan Avocado Ice Cream

Ingredients

 

° 2 ripe Haas avocados

° 1-1/2 cans (about 600g) coconut milk (full fat)  (or 1 can coconut milk and 125g heavy cream for dairy friendly folks)

° 100g white cane sugar

° 1/2 tsp vanilla extract (rum should work too)

° pinch of finely ground sea salt

° squeeze of fresh lime juice

 

Technique

 

° Scoop out the avocado  put it in a food processor

° Add coconut milk, sugar, vanilla, salt, lime juice and puree until completely smooth. Chill in a refrigerator for at least four hour

° churn freeze

 

there are many potential projects

First hand historical accounts can be fascinating.  One of the joys of being at the Bell Telephone Laboratories in the day was contact with the folks who had invented much of the modern world - the stories of discovery, invention, implementation and innovation were often spellbinding.   But as fantastic as these stories were, I had recently come from an even richer source.

 

From the late 70s through the early 80s I was doing particle physics at Brookhaven National Laboratories.  The accelerator and many of the core experimental areas were run by dedicated groups.  Lots of accelerator physics as well as applied physics, mechanical, electrical engineering and computer science.  Some of these guys went back to Los Alamos and the first two decades of the cold war.  To call the place a rich story environment was understatement.

 

Details of the Manhattan Project were amazing and shocking.  Some of it seemed outlandish at the time, but I've seen it verified as documents have been declassified.  These guys were pushing the limits of what was possible and were fueled by science, imagination, often bizarre leadership, essentially infinite budgets and a willingness to take enormous - even life-threatening - risks.  

 

A guy I'll call Tom was a technician on the Multiple Particle Spectrometer.  One of those guys who could do mechanical and electrical engineering and make almost anything work.  He was bumping into retirement age and loved to talk about the old days.   It seems Tom had come from General Atomics and was one of the engineers involved in one of the more unusual projects ever - the Orion Project.

 

If you are building a rocket, you want to get the most energy possible per unit mass from whatever fuel you are using.  Chemical rockets burning a mixture of hydrogen and oxygen are close to their theoretical limit.  They work well enough for orbiting stuff in low earth orbit for about $10,000 a pound.  Going to the Moon is more expensive and travel through the solar system is expensive and very slow - you are limited to about 150,000 miles per hour even when you play tricks harnessing the gravity of other planets.¹  150,000 miles per hour may seen fast, but the Solar System is huge and interstellar space is unimaginably big.

 

Space is big. You just won't believe how vastly, hugely , mind-bogglingly big it is.  I mean, you may think it's a long way down the road to the drug store, but that's just peanuts to space. - Douglas Adams

 

There are ways around this.  Specific impulse is a measure of the efficiency of a rocket.  Very loosely it is the pounds of thrust produced divided by how many pounds of fuel are burned in a second.  The best chemical rockets have specific impulses of about 450 seconds.  Ion rockets produce tiny amounts of thrust, but over very long times and are comparatively parsimonious - they have specific impulses of 3,000 to over 20,000 seconds and would reduce travel times within the solar system.

 

But we can do better..

 

To get amazingly high specific impulses you can always use a very dense source of energy - nuclear energy for example.  Atomic bombs would have not only specific impulse, but also a very high thrust ...  the best of ion and chemical rockets, but with a few pesky side effects.

 

The Orion project came out of a most unusual paper by Ulam and Reines in 1947.  Physics guys (astonishing smart ones), they worked out a "practical" spaceship that used nuclear energy.  Although hybrid nuclear rockets that heated a gas were later developed, this was much more dramatic.  You open a little door on the bottom of a robust shield on your rocket, toss out an atom bomb, close the door, and set off the bomb.

 

Freeman Dyson picked up the thread and left the Institute for Advanced Study at Princeton for awhile to work on it at General Atomics.  Staggering crazy stuff, but it became a government funded project.  It penciled out on the blackboard and the physics worked out just fine.

 

Tom worked for Dyson and was one of the people who worked on a dynamite powered vehicle that was to investigate stability - a critical piece of the transition from physics to a technology.  He described it as loud and frightening - far and away the craziest thing he had ever worked on.  Insane and impractical as it is, if we wanted to make it to the next star in under a few hundred years ...

 

A bit of searching turns up a bit of BBC footage - a must watch!²

There are a lot of things that people can do if they have the will.  I'm convinced we could have tackled global warming if we really thought it important (we don't).  Because we can't take the easy way out we now are facing the more difficult challenge of sorting out the repercussions - hopefully we'll make the problems for our kids and grandkids a bit more manageable.   I'm not quite as optimistic on the this one. It will be enormously expensive. 

 

The trigger for all of this was Elon Musk's Hyperloop announcement.  There have been numerous proposals for making use of the right of way for roads, train tracks and even pipelines (monorails for example), and many variants on running trains suspended on air cushions or magnetic fields.  Lockheed, MIT and the US Department of Commerce had a project that was to connect major East Coast cities with a levitated tube train in a partially evacuated tube at about 400 mph. It looked really good on paper, but problems cropped up as people thought about the technical issues.  Robert Salter of RAND did a lot of work in the 70s on a dramatic underground version (tunneling is too expensive though) and more recently a 1000 kilometer per  hour Chinese project based on a modification of an earlier American design.

 

Elon's need is to reduce air pressure - he talks about 100 pascals or about a thousandth of atmospheric pressure at sea level.  A quick back of the envelope calculation shows you should be able to keep a vehicle like his clipping along at 700 miles per hour with about 100 kilowatts of power.  That part is enticing.  Making a long tube at that pressure isn't going to be inexpensive and one can think of any number of other issues.  I certainly haven't studied it deeply, but have issues with some of the cost estimates.

 

He is a charismatic leader and that is important in getting people lined up behind a project.  He is also working in areas much more interesting that helping people consume more stuff.  But there are a lot of really interesting projects that can make a huge difference.  Many are much more speculative than this (although I would argue his cost estimates are exceptionally speculative) that also don't violate physics , but the potential payoffs are enormous.  I'm not convinced fast point-to-point ground human transit over distances of about 500 miles give or take is a central problem.  There are other transportation issues much more pressing and there is still optimization to be done in most areas.  But my hat is off to him for stirring the pot at bit.  I'll be looking at his proposal more critically when there is time.  On the surface at the physics level there isn't anything wrong with it, but it may not make sense technologically where issues like human factors, safety, cost and politics rear their heads.

 

One fact often lost on Silicon Valley is that things like energy an infrastructure are really expensive and slow moving.  You don't see a lot of direct invention that is turned into large scale infrastructure.  Even something like SpaceX is a re-envisioning of a technology that was largely stable by the end of the 1960s.  The innovation is making it less expensive (and that is non-trivial), but the proof of concept existed.  It is even more true for the electric car.   This is not meant to diminish what Elon has done, but rather to underscore just how difficult the big problems are.

 

One of the things I like to do is take a January sabbatical of about two weeks to study something I know little about.  Fifteen years ago it was telegraphy.  I was interested in learning about its social impacts, but also found that physical transport through intranets of pneumatic tubes was a big deal in the day.  It still exists in banks and hospitals and the postal service was close to considering it for general mail delivery in the US. (elaborate systems involving thousands of miles of tubing were installed in other countries).    We talk about the Internet of things - we had intranets and even some connected internets that moved things more than a century ago.

 

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¹ You can get about 40,000 miles per hour from a chemical rocket designed for this sort of exploration and pick up more using gravity assist by slingshotting off of planets along the way.  Basically you transfer some of the kinetic energy of a planet, slowing it down a tiny amount, into the much less massive spacecraft, speeding it up in the process.   The record holders are at about 150,000 mph and a bit more is possible.

² Freeman's son George wrote a book on the subject  Project Orion: The True Story of the Atomic Spaceship.  I recommend it along with his latest book, Turing's Cathedral.

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Recipe Corner

 

No recipe, but something that may revolutionize your homemade pizza and flatbread.  Steel is a much better heat conductor and storage medium than a pizza stone.  You heat a slab for about 45 minutes in a hot (550°F) oven or covered grill and then cook away.  The results are fantastic!    Rather than having someone cut the steel and worrying about grades, the Baking Steel works very well.  If you want to do several pizzas and have something made, you may want to go 3/8 or 1/2" thick, but remember to have the edges beveled to prevent cuts and handle it carefully these are heavy and stay hot for a long time.

These are much less expensive than a dedicated $10k outdoor brick pizza oven, although my hat is off to you if you are serious enough to go that route.

 

 

playing and learning

This morning wasn't great for Perseid watching.  At 3:30am there were some high scattered clouds along with the light pollution common to this part of New Jersey.  In an hour's time I only saw five, but I have a low threshold for entertainment so it was completely worth the effort.  There are still a few days to watch and tomorrow morning and the next should be much better assuming the sky is transparent enough.

 

I've been watching the shower - or at least trying to - since I was 12.  Somewhere in high school I discovered meteor trails would make antennas.   They are just narrow columns of ionized atmosphere about 50 kilometers long.  You could "listen" to them by tuning a radio to a line of sight radio transmitter that was over the horizon.  Normally you wouldn't hear anything, but suddenly there would be a few seconds of signal.  North Central Montana was mostly devoid of commercial FM stations, so I picked one in Edmonton and waited.  Meteors passing overhead would ionize nice trials making effective antennas that would reflect the signal back to Earth and to my radio.¹  Listening to radio signal scatter from ionized paths is more challenging in the highly populated East Coast, but there is an easy way out and anyone can enjoy it.  

 

The Air Force send a ridiculously powerful continuous wave signal into space from a few transmitters around the clock as part of their Space Surveillance Radar program.  A nifty way to monitor space stuff, but also a wonderfully strong signal to use for finding meteors.  Stan Nelson lives in Roswell, NM (no jokes please) and has a receiver tuned to a ~217 MHz transmitter in Lake Kickapoo, TX.  He encodes the resulting signal in AAC and streams it to the Internet.  

 

listen

 

Understanding nature a bit more deeply greatly enhances one's appreciation of it and gives clues that help you find more beauty.

 

I was thinking about play and education as a friend and I were talking after a conference on the education experiments taking place in colleges and universities these days.  We're already in a post MOOC world - not terribly surprising as most of the experiments will produce no more than brief flashes in the pan as the issues are understood more deeply.

 

In the natural sciences it is critical and perhaps the nature of education is a bit different, so we may be looking at the problem with very biased filters, but both of us are proponents of hand's on education.   I learned a good deal of optics as well as learning to deal with failure building my first telescope.  Amateur radio taught the practical side of Maxwell's Equations and so on.  I was hooked and I still build things to get a better look at nature.  And while it is easy to lament the fading of amateur radio and telescope building, there are many new opportunities - some of them wonderful.

 

Last week I played with a Bigshot camera.²  An easy to build $90 kit, it can teach more than a few bits of science and engineering to kids (or to their STEM rusty parents) and has the added feature of being sort of good enough to do a bit of real photography.  I'm a strong proponent of STEAM education (STEM + Art) and photography is a natural path.

 

There are bits and snatches of lesson plans and starting points for the curious on the Bigshot site, but it can be greatly enhanced.  Think of it as a hardware kickstarter for the imagination.

 

We need more projects like the Bigshot and more mentorship, but there are many branches you can take with photography.  Digital camera sensor arrays are sensitive to the infrared and it isn't a big deal to modify a camera to explore the infrared world.  I wouldn't do this with a new camera, but most of us have one or two old point and shoots sitting around.  Some can be reprogrammed to make time lapse movies or you can buy an inexpensive GoPro - used ones can be had for very little thanks to an aggressive new model schedule.  Connect a camera to a cheap microscope or buy a cheap portable digital microscope to take out into the woods.

 

so many ways to use a bit of tech to play with nature and it only gets better with experience...

 

(The opening photo is a Perseid photographed from above by Ron Garan orbiting in the ISS.)

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¹ This is reliable enough that meteor burst communications is a cheap and reliable way to access remote data sources. Snowpack in the Western US is transmitted this way 

² A SciAm piece on the Bigshot project - one of the better education projects funded by the Google of old.  Most kids will have better cameras in their phones, but they won't learn very much about how cameras work.  This is a potentially rich vein for them to mine.

 

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Recipe Corner

 

A chef friend told me you can make a tasascoish sauce quickly in a pressure cooker.  Play around with the types of peppers and vinegars.  The first try was a success and there is enormous room for experimentation.  

 

Homemade Tabasco Sauce

 

Ingredients

 

° 450 g (1 pound) hot peppers - your choice depending on the intensity you want.  You can thin with ripe bell 

° about 1-2/3 cup cider vinegar ..  experiment!

° 2 tsp salt (a smoked salt was recommended, I just used a non-iodized sea salt)

 

Technique

 

° Chop the peppers and add to your pressure cooker

° add enough vinegar to cover (1-2/3 c for me) and salt

° close it up, crank the heat and when you are at pressure lower the heat to the setting up use to maintain pressure and cook for a minute.  When the time is up move the cooker off the burner and wait for it to come to atmospheric pressure naturally. (10 minutes for me)

° Puree the pepper mash with an immersion blender and strain into clean sealable bottles.  It will freeze if you want to store it a long time.

 

seeing things in a new light

In the next month millions of students will be back in colleges and universities starting into a new term.  Some will signal their interests by what they wear.  You may have seen physics and electrical engineering students wearing a certain tee..

 

Maxwell's equations are one of the most beautiful achievements in physics, describing how electric and magnetic fields are generated by each other and by currents and charges.¹  Electromagnetism is one of the four basic forces of physics - a force fundamental to chemistry and therefore biology and one that, as we understood it more deeply, gave us much of our current technology.  

 

The precise formulation of the time-space laws was the work of Maxwell. Imagine his feelings when the differential equations he had formulated proved to him that electromagnetic fields spread in the form of polarized waves, and at the speed of light! To few men in the world has such an experience been vouchsafed ... it took physicists some decades to grasp the full significance of Maxwell's discovery, so bold was the leap that his genius forced upon the conceptions of his fellow workers.  - A. Einstein Science May 24, 1940

 

Revolutionary is perhaps not a sufficiently strong term

 

In college a physics student first encounters them as a freshman, again as a junior and then as a first year graduate student going in more deeply each time.  They are a great path to learn a bit of the language of physics - mathematics - along the way.  

 

Early on you perform a simple manipulation and get a curious result.  This turns out to be a wave equation.   It tells you that the fields involved propagate as waves at the speed of light.  My advisor noted that those who see this is beautiful go on into physics and those who don't leave fairly soon.  All of us who find passion in things hear the bits of poetry.  Perhaps this for a physicist, real poetry for a poet, and the kinesthetic manifestation of flow for an athlete.   We all have our own language of beauty.

 

The term light usually refers to what we can see with our eyes, but it is a very small part of the electromagnetic spectrum.  The wavelengths of visible light range from about four to seven tenths of a micron - with blue on the short side and red on the longer.  But the spectrum extends to enormously long wavelengths - a section we call radio as well as to very short ones that include X-rays.

 

We only sense a small part of what nature offers with our senses.  I won't dwell on that, but go to this earlier post for a bit of necessary detail.  Using our minds we have developed methods to sense what is going on in nature - we have dramatically increased the scale of what we can "see".

 

The trigger for this post was a bit of visual story telling - namely what WiFi would look like if we could see it.  The problem is it is just story telling and happens to be inaccurate - a real danger of story telling that is pretty.  You get a sense of what things would look like from the basic physics.  It is a mathematical abstraction, but turns out to be much more beautiful.  

 

Here is a note I sent to a good friend who pointed to the site:

 

The visualizations are wrong.  Pretty, but wrong.

A few points…

Let's saw our eyes were sensitive to ten centimeter electromagnetic radiation.  Probably the first problem is we don't see the photons because to have vision the photon has to strike our eye.  Vision comes when the radiation reflects, or is transmitted through something or a vacuum.  

We would see things that looked sort of the same except very blurry.  Things smaller than about ten centimeters would be completely blurry as would any feature roughly wavelength-ish.  There would be a lot of diffraction effects evident.  What is transparent and opaque would shift as some objects (like a wood wall) are fairly transparent in these bands.

So let's say this is a depiction of what the photon is doing rather than what we're seeing.  The images are still wrong.  An electric and a magnetic field strength changes with time  and this varies with position (or time as it is propagating).  

There is the issue of signal encoding.  Without information a constant frequency is just a simple tone.  The frequency, amplitude, phase or polarization can be modulated and you get schemes like frequency-shift keying for digital signaling (sort of a modified frequency modulation).  With light you detect the amplitude of the intensity which is the square of the field. Somehow our eyes would have to deal with the modulation to notice any signal (which would be at a lower rate - usually a much lower rate - than the frequency).

There are other issues, but this piece is built on incorrect physics.  What is really happening is much more complex and beautiful.  Our our eyes deal with light and forming images from it is much more beautiful and wonderful.   

Thinking about what it would really look like is a nice exercise for learning the underlying physics as well as how radio waves interact with the world around them.  It is something the radio engineers have to get right - or at least good enough.  And, when you think about them deeply you realize the current rules for spectrum allocation are more a function of receiver design - and an antiquated notion that goes back about 80 years - than physics.  Our wireless spectrum shortage turns out to be driven by arbitrary laws rather than basic physics.²

 

Ending with a bit of history...  

 

Decades of research preceded Maxwell's grand synthesis and then another twenty or so years before the commercial world began to make use of the result (Tesla and Steinmetz built their work on its foundation and later all of radio came about).  One of the great experimentalists before Maxwell was Michael Faraday.³  When William Gladstone, then Chancellor of the Exchequer, asked about the practical value of electricity in 1850, Faraday replied:

 

 One day sir, you may tax it

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¹ James Clerk Maxwell published an early form beginning in 1861.  Few understood them at the time as the form was so obtuse.  In about 20 years modern formulations of the equations appeared and their use began to become realized.  It turns out they are an approximation of a deeper view of electromagnetism - quantum electrodynamics.  But they work perfectly well for most of the world and technology we interact with as humans.

² This creates artificial scarcity - something exploited by those who "own" spectrum.  They complain, but it allows them to sell wireless connectivity at a very high price.

³ Faraday, in addition to being one of the great scientific minds of the 19^th century, was also the Carl Sagan and Neil deGrasse Tyson of his day - a great popularizer of science. He excelled at the art of the public lecture and his Christmas lectures for young people at the Royal Institute were famous. The six part series on the Chemical History of the Candle is brilliant and wonderful even today - you can read it courtesy of Brewster's great archive.

 

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Recipe Corner

two sketches

 

Chickpea Salad Sandwiches

More of a sketch than a recipe - use your own creativity here.  Rather than making egg salad sandwiches with eggs, use chickpeas.  The trick is to use cooked chickpeas and mash em with a fork rather than something which grinds them up finer.  I used a 15 oz can of cooked chickpeas, 1/4 cup of mayo (use vegan mayo if you like), and the goodies that make up the rest of an egg salad - I used finely chopped celery, onion and salt, pepper, a splash of lemon juice, a bit of crushed pickle, and some curry powder.  

 

I make a sandwich with a good bread, sliced tomato, lettuce and pickles, avocado or whatever you like.

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on someone's suggestion another sketch

 

BBQed Ice Cream Sandwiches

 

I saw a recipe and tried this variation.

 

Cut inch thick slices of brioche bread, butter lightly on each side and grill until crisply darkened.  Now put a big scoop of ice cream on a sheet and top with a fruit topping (I used a blueberry jam) and another piece of brioche.  It might even work with pound cake if you use some care.