omenti

frozen bubbles

minipost

 

Someone asked about the frozen bubbles we made years ago at Stony Brook.  It turns out that bubbles freeze (there's some interesting physics going on) with interesting patterns.¹  I've never tried to photograph them as (a) only about ten percent of my bubbles freeze properly and (b) I'm not a photographer. 

 

The recipe I've used forever is 

200 ml warm water (warm enough to dissolve the rest of the ingredients)

35 ml corn syrup

20 ml dish soap

25 grams (2 tbl white sugar)

a cold calm day or evening with some good lighting.  I generally find temperatures between -15°C and -25° C  best.  One can experiment with the final water temperature as a first step.  If you're really serious you could try a walk-in freezer. (not that I haven't been tempted)

Here's an excellent video on YouTube.

__________

¹ Here's my hypothesis of what's going on.  A liquid gives off a bit of heat when it freezes - the latent heat of fusion.  Those vibrating water molecules lock into a structure and the energy of the water molecules motion has to go somewhere.  When the bubble lands on a cold surface it begins to freeze at the point of contact. A ring shaped freezing front proceeds up the bubble.  As the region freezes a bit of heat goes to the liquid part of the bubble in the immediate area that hasn't frozen causing a flow of slightly warmed water that moves upwards.  This flow grows and puts stress on the freezing front causing bits of new ice to break off and slide around the still liquid part of the bubble.   If I'm right the illusion that individual freezing zones form is just that - an illusion - and an artifact of the single moving ring.

The corn syrup gives sturdier bubbles.. the white sugar doesn't totally dissolve and gives good nucleation sites for crystal formation.

Of course this is just a guess that would need testing.

 

 

meshes and trees

A few weeks ago an unexpected email arrived from Germany.  A physics postdoc and had come across an ancient transition radiation detector in storage at CERN a few months before.  It seemed like it could be useful in an experiment her group was thinking about. She had a few questions and it turned out I was the best person to talk to.

 

Many people think science is done with sparkling new state-of-the-art kit.  A few pieces perhaps, but very old equipment is updated, repaired and repurposed where it might be useful.  An experiment I was part of in the early 80s required a very large magnet.  The best bet was one that had been a cyclotron at Berkeley fifty years earlier.  It worked well,  but we had to tap into institutional knowledge that had migrated out of physics entirely.  That knowledge combined with technology that hadn't been invented at the time gave us something fantastic.  

 

I have no idea how my old detector made its way from Brookhaven National Laboratories to CERN.  The documentation and lab books were packed with it, but they made assumptions that the people who built it would be involved.   That meant me.  I asked for photos of some of the lab book pages and then it came back.  I listened to her ideas, offered some suggestions and wished we had her experience back then..  Of course that experience came years later.

 

These interactions spanning several decades may not be common, but twenty year interactions of hardware, software and people.  It's all a mesh.  Old apparatus islands that have been repurposed and grafted onto new apparatus.  It's an organic process that's difficult to map out and impossible to predict.   Diagrams it would look like flocks of meshes that are grafted together with a lot of institutional knowledge.  No one has a complete picture and local expertise is critical.  A team sport spanning decades.  It isn't easy, but it works.

 

Last week I came across something by Frank Oppenheimer in the 30s:

 

 

 

It's one of the better commentaries I've seen on how science progresses.  The same is probably true for many other fields.  I suspect it's true for any infrastructure involved in messy and complex endeavors where creativity and insight come into play.  

 

I've been fascinated watching the techno-solutionist approach to cities - the so-called smart city.  These are often based on a "start with internet and build up" model.  They try to measure everything and automate control.  Sensors embedded everywhere and tree-like computational structures making decisions to smooth out - well - everything.  A fundamental problem is we don't know what is being measured and what the biases - social and technical - are.   A simple truth I've learned from my exposure to sports science is you have to know exactly what's being measured and exactly where it is useful. (duh!)   Often current measurements and/or models just don't work.  Something complex like a city is that on steroids with the tree-like information structures introducing a certain rigidity.

 

There are a few types of people who thrive in the messy environment of a city.  Impedance matchers - those who can connect and explain across disciplines, and synthesizers come to mind.  (many others too - artists for example)  They respond to intellectual and system friction and help spark creativity. They're ground zero essentials for  creativity and invention.  I have doubts that the techno-solutionist cities can be terribly creative in the long run.

a song by Malvina Reynolds comes to mind

 

five years past a mentor

Nancy White is someone who knows a thing or two about the dynamics and information flow in meetings and collaborations.  She recently reposted a bit on the value of the clown in a meeting.   I was fortunate enough to work with a magnificent clown who also happened to be a mathematician and the most joyfully playful person I've met.  

 

In a few weeks five years will have passed since Norm's sudden death.  I wrote a short remembrance of what he meant to me that evening.  I'm always been a believer in the value of playfulness in what you do, but he helped me realize the sky didn't  begin to touch the limit.  

 

Here it is.  

(yes - he often wore curious hats)

May you be so lucky as to have the powerful magic of a joyful and brilliant clown in your midst.

 

 

a dive into snowflakes

miniost

Derek Muller interviews Ken Libbrecht.  Ken is an astrophysicist, but like many scientists his curiosity extends past his core interest.  He's a great example of someone making progress in one of those small areas not many people worry about.  His enthusiasm comes through communicating why people do science.

This is so good!