omenti

from math to music and physics to phys ed

In the early 18^th century commerce had become a primary driver for education the American colonies.  Physical connectivity to move goods and information was growing rapidly.  Stores were moving beyond the basics and it was becoming necessary to let potential customers know what was available.  The amount of information was growing rapidly and with it, the necessity of connecting it with the consuming public.  Teaching as many as possible how to read and do arithmetic had become important.  

 

We've seen many periods of change in education.  Public land grant colleges, the advent of the University laboratory (one of the largest and most enduring inventions of the 19^th century), full education for women and minorities, physical education, education for it's own sake vs vocational training, the dramatic change to science education during the Cold War and the failed experiment of teaching real mathematics.  Some of these have gone through cycles and now we stand at a time where it seems clear a shift of emphasis is necessary.

 

I've written a fair amount of my experience - the gifts of play, boredom and freedom that my parents gave and two mentors separated by time and space that allowed me to focus on a core interest in such a way that I managed to learn a bit about curiosity.  I've learned and taught at a variety of levels and have some ideas on what I'd like to see change.  I also suspect many of my ideas aren't that well informed and some are controversial (in particular my views on the current STEM emphasis, how to change math and science education, precollege focus, critical thinking, physical education, and practical skills training).

 

What I want to propose is a bit of homework.  The readership here is small, but extremely diverse.    I'd love to collect ideas from as many who would like to write something and post them in a few weeks,  As a constraint, keep it to one to four ideas, for pre-college education.  Feel free to point out anything you feel is being done exceptionally well that should be more broadly applied, Anything from a paragraph or two  to a few pages if inspiration hits.  Pencils down on January 14^th.  Let me know if you want it to be anonymous or associate your name.   Feel free to include anything other than text.  I'll collect everything including my bit into a long post a few days later. 

 

Remember that we all have a different take on this education thing.  Everyone's ideas are potentially interesting, so don't worry if you're not in the business.

And if you want to make a video, that's ok too...

 

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Recipe corner

 

My mother died a year ago ..  going through some old things this recipe appeared.  It's from her mother, but makes a fine gingerbread.  Better with vanilla ice cream than whipped cream, but also good by itself.

 

 

what does dim mean and a most unusual job

You're outside on a dark and starry night wondering about those stars.  Is someone out there? You take your flashlight out and point it at the sky.  Your message in a bottle tossed into the cosmos.   I'm guessing most of you did it when you were a kid.  The problem is it doesn't work.  The light you send skyward is scattered or absorbed before it gets out of the atmosphere. At least your imagination was fired - what would it take,  There are people who point lasers beams skyward  and that leads to one of the most unusual job openings I've ever seen.  But more on that later,  there's another interesting question to ask first.

 

Our eyes are amazing at what they do.  We get reasonably detailed color images along with less detailed, but much more sensitive night vision.  We usually think about owls as having some of the best night vision eyes.  They're pretty good, but some frogs can detect a single photon of light.  So image this.  You're a frog watching a light that glows with an unwavering brightness.  If you were a space frog it might be the Sun.   You measure the brightness of the light and then start a journey outwards.  Twice as far from the source the light appears a quarter as bright.  Three times as far and it's a ninth as bright.  One hundred times and it's one ten thousandth it's original brightness.  The measured brightness at your distance goes as 1/r² where r is the distance.  The inverse square law.¹ You continue on and and the light gets dimmer and dimmer.  How did can it get and what would it look like?  I posed the question to a class of premed students I was teaching physics to..

 

The light gets dimmer to a point - the single photon point.  Rather than diminishing further it begins to flash at that brightness. .  At first are flashes most of the time, but travel further and there an increasing number fleshless regions.  Add up the energy you receive - the number of photons over some unit of time.  The frog is  bored and haven't croaked yet, so it plots the energy over some amount of time .. just the number of photons  (flashes) it sees in some length of time.  The curve is still the inverse square law.  

 

Light, as it happens, comes in chucks.  In physicsy terms it's quantized and that chunk is a photon.²

 

When first encountered the paper on the sensitivity of frog's eyes I was blown away.  For perspective a 60 watt equivalent light bulb emit's about ten billion photons a second.   The back of the envelope suggests the Sun would start to look like a blinking single photon about 1000 light years out - the range of our deep space frog. 

 

If you're sending information you have to worry about how quickly you can flash the light to begin with.  If your receiver is seeing a bright light or radio signal (radio is just longer wavelength photons), you can send information at a fast clip.  If it's very dim things get slow.  Even with huge exotic antenna arrays the science from the New Horizons spacecraft that flew by Pluto had to be recorded and sent back over a period of months,  NASA and JPL have been experimenting with deep space laser communication systems. The idea here is a laser beam can be made to not spread out much and will appear bright,  HDTV from Mars orbit can be done.   As long as you don't have to go through the atmosphere.  

 

We've almost circled  back to the beginning - the people who shoot laser beams skyward.  But the atmosphere absorbs and scatters so much.  What's going on?  

 

You can point a very bright, highly culminated beam of laser light to the sky.  Some small lasers are bright enough to travel through a few miles of atmosphere and still be focused and bright enough to temporally blind a pilot.  In fact it's a federal crime to shine a laser at an airplane.

 

There are people who shine extremely powerful lasers skyward legally.  The atmosphere can be thought of as a sea of small regions about the size of your hand. They have slightly different optical characteristics than their neighbors.  Their turbulent movement is what causes stars to twinkle. They represent an enormous limiting factor to the resolution of telescopes with mirrors larger than a half meter in diameter.

 

The trick is to look at a reference star near the object you're studying.  You know where it is so you image it, look at it's new position, do a bit of math and change the geometry of your optics in real time to adapt.  Simple in principle, but difficult in practice, it has revolutionized optical and infrared astronomy at a half dozen of the largest observatories in the world.

 

One of the problems is you need a fairly bright reference star and for about 99.99% of interesting astronomy there aren't any suitable stars that are close enough to use.   Astronomers get around that by making their own reference stars.  The standard technique is to use a very powerful pumped dye laser to create a yellow beam with a wavelength of 589nm..  

 

The laser is pulsed on for a short time - microseconds - and the beam soars skyward.  For the first 30 kilometers there's enough atmosphere to scatter most of the light so it's a visible yellow line. At about 95 km above the Earth it encounters a layer of sodium atoms - leftovers from constant bombardment of our atmosphere with micrometeorites.  589nm is a resonant frequency of atomic sodium so they get excited and then spontaneously de-excite emitting yellow light in all directions.  A little artificial guide star shines during the pulse.  Some of it's light makes it back to the telescope through nearly the same path light from the astronomy target has to travel.  Everything you need to compute your mirror changes.  All of this happens about a thousand times a second.  The process works so well that the largest 'scopes on Earth now resolve better than the Hubble Space Telescope, although it still has other advantages.

 

That upward beam is really bright.  It's only on for about a tenth of a percent of the time, but it could blind anyone on an airplane who happened to be in the way.   You get around this with one of the most exotic jobs I know of - a night watch for the 21st century.

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¹ The way to think about it is to recognize light travels in a straight line.  Image two imaginary spheres - one is  one unit of length away from from a glowing sphere and the other two units.  If you pick a region with any area on the first sphere (say 10 square inches) it covers a fraction of the first sphere that is four times larger than the fraction covered by the same area on the second sphere because the area of the spheres goes as the square of their radius 4*Π*r²

² In your physics classes you probably learned light can be a particle and a wave.  You can think of the photon as the particle of light.  Well..  and this would take too much to get into ...  the particle/wave duality model is an artifact about how people saw quantum mechanics in 20s and 30s.   I'll just state what we now know ... everything's just a wave.  But unless you are deep into physics it's probably safest to think about particle wave duality.

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Recipe Corner

 

Really easy and just right for the cooler weather

 

White Bean Toast 

 

Ingredients

 

° extra virgin olive oil

° 6 slices of crusty whole grain bread (or whatever constitutes excellent toast for you)

° 1 clove garlic, minced

° 1 tsp chopped fresh rosemary

°  a 15oz can of no salt cannellini beans drained and rinsed

° 2 tbl lemon juice

°  salt

° 2 tsp chopped parsley

° bit of red pepper flakes

 

Technique

 

° oven to 425°F.  Use 1 tbl of EVOO and brush one side of each piece of toast.  Arrange face up on a sheet and toast on top rack until brown and crisp.

° heat 2 tbl of EVOO in a skillet over medium heat.  Add garlic and rosemary when the oil is hot and cook for a minute and remove from heat.

° add beans, lemon juice and salt and mash some of the beans a bit to give a variety of textures and some whole beans.

° spread over the toast, drizzle on some good EVOO, sprinkle on parsley and red pepper flakes.

 

communication

 

It's almost Christmas and the candles are coming out.

 

Candles.    And Michael Faraday's remarkable gift to young people.  He's way up on my own list of favorite scientists.  In addition to making fundamental contributions to physics (like field theory even though he was poorly schooled in math), he happened to be an excellent public speaker.  Every year there would be Christmas lectures for children.  A legendary set of six lectures on the chemistry and physics of candle flames was given in 1848. While a good deal of deeper understanding has taken place, much of the lecture is still relevant.  Watch a modern performance!¹  Here's a Project Gutenberg link to the text.

 

My advisor believed his students should be able to describe their Ph.D.thesis work to a group of smart high school students.  That proved to be one of the most difficult and poorly received talks I've given.  (I've improved over the years:-)  This sort of challenge is becoming more common ..  Alan Alda's Flame Challenge is wonderful..  A question is presented every year and people attempt to explain it to groups of eleven year old students from around the world who then select a winner.    There is the five level challenge..  try explain your work to a grade school, high school, undergrad, and graduate students along with having a meaningful chat with another expert in the field.  My favorite is Neville Sanjana talking about CRISPR.  I think Faraday would have been thrilled.

And finally there's the Dance your Ph.D. competition open to STEM Ph.D.s...  This year's winner was Nancy Scherich with a focus on braid theory - a brach of topology that looks at knots in higher dimensional spaces.  Hula hoops, linear algebra and murder! 

I'm a terrible dancer, but I guess something could have been done with infrared freedom and ultraviolet slavery and the production of charm quarks...  Then again...

 

Now a few questions:

 

How important is it to communicate the beauty of what you are interested in to non-specialists?  How is it usually done and how would you improve it?  And how do you spark and sustain an interest in some?  

 

By the way.  The Christmas Lectures have continued to this day.

 

Lessons and Carols

 

And a late (10^th of December) addition

Music

 

I think songs would be great for science communication.  Although They Might Be Giants have a few good ones, pickings are sparse.  Sadly most scientists are not good singer songwriters and coming up with lyrics that communicate real science is not easy.  

 

There are exceptions.  Henry Reich put some nice lyrics to Twinkle, Twinkle, Little Star that are sound and current.  They work across ages and levels of astronomy experience.  The first time I heard it I thought I found something wrong, but another listen and some physics told me it was ok.²

 

twinkle twinkle little star
you look small cause you are far
lightyears out from here to there
your light is distorted by the air
so you twinkle twinkle little star
adaptive optics shows you as you are

twinkle twinkle little star
you must be a small pulsar
out away from earth you drift
this is known from you red shift
twinkle twinkle spinning star
degenerate neutrons are what you are

twinkle twinkle little star
supernova, au revoir
you got so big to big perhaps
electron capture core collapse
twinkle twinkle former star
a black holes all you now are

twinkle twinkle little star
wait actually no you’re a meteor
breaking up in the atmosphere
i wish id known you’d end up here
twinkle twinkle shooting star
became a meteorite that hit my car

 

Maybe it is enough to get people thinking and asking questions.    So in addition to dance your Ph.D., I'd love to see a sing your Ph.D. - or just sing your research.   Collaboration with a real singer is ok... witness this version of Howie Day's Collide sung by... Howie Day. The physics is quite up to date - get in touch if you want anything decoded.

 

Just don't get me started on the Big Bang Theory show...

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¹  The Faraday Candle Lectures

Introduction to Michael Faraday’s Chemical History of a Candle

Lecture One: A Candle: Sources of its Flame 

Lecture Two: Brightness of the Flame

Lecture Three: Products of Combustion

Lecture Four: The Nature of the Atmosphere

Lecture Five: Respiration & its Analogy to the Burning of a Candle

 

They've also produced a version with commentary if you want more after watching the remade lecture

Lecture One: A Candle: Sources of its Flame (Commentary version)

Lecture Two: Brightness of the Flame (Commentary version)

Lecture Three: Products of Combustion (Commentary version) 

Lecture Four: The Nature of the Atmosphere (Commentary version) 

Lecture Five: Respiration & its Analogy to the Burning of a Candle (Commentary version) 

 

²  Using redshift only works for distant galaxies and pulsars are observed in our galaxy (they're in other galaxies, but are too faint to measure a redshift, let alone detect).  Re-reading 

you must be a small pulsar
out away from earth you drift
this is known from you red shift

It is becomes clear that it is drifting away and we know that by it's redshift..  so the song is correct.