Friday, August 27, 2010

Magnetic Sand

A couple of weeks ago I went down to the beach in Aptos with my son.  Charlie had a magnet with him that he had been playing with as we walked out of the house.  When we got to the beach and started walking out over the sand, Charlie saw what looked like a piece of metal, and he reached down to pick it up by the magnet.  To our astonishment a bunch of sand jumped up onto his magnet.  "Whoa," we said in unison.

To some readers of this blog it may not be new information that there is a lot of magnetic sand in the beaches of California.  The material is magnetite, Fe3O4, a non-rusty oxide of iron.  It is surprisingly fun to collect the stuff, and with a good magnet you can collect five or ten pounds in an hour.  It's also very satisfying to purify it, which you can do by spreading it out thinly on a clean surface, then sucking it up with the magnet, and throwing away what's left.  Two passes of this process leaves you with a pure black almost satin smooth substance.

Of course it's fun to see how the sand stands up in needles when there is a magnet below (or above), but I'm trying to think of something *truly cool* to do with it.  I first thought that if I put it inside a plastic pipe I could get it to run along inside by activating coils along the pipe, but it's not that simple.  You would think (at least I did) that the stuff would just behave like the core of a solenoid, and jump into any coil.  But it's sand, so it is more interested to stretch itself out along the magnetic lines of force than it is to jump to the center of the coil.  Since this blog is supposedly a two-way thing, I'm curious if any of you/us know of, or can think of, something incredibly cool to do with this stuff.

If you live on the west coast (I can't vouch for the east coast), by all means take a magnet with you next time you're headed for the beach, and see what you find.  Look for darker patches (especially on dunes where the wind preferentially blows the lighter silica away), and come to Aptos if you are stuck.  A geologist who stopped by told me that the beach at Fort Funston has especially high magnetic sand content.

Have fun.

Monday, April 26, 2010

Amazing Volcano Pictures

Volcano and lightning
  -- it doesn't get much better than that.


In case you haven’t already heard about Node.JS, here is something cool:

   Node.JS -- the project home

   a presentation about it

   an enthusiastic article about it

Node.js is an “evented I/O framework” built on top of Google’s V8 JavaScript engine. It uses an event-based programming model to (a) provide deadlock-free concurrency, and (b) build a server that can handle many pending requests without the overhead of suspended threads. It’s a bit like the Erlang programming model in JavaScript, although you don't get the same kind of multicore leverage without load balancing or intelligent use of worker processes.

What this gives you is actual high performance in a system that is completely dynamic and malleable (hence my interest). You could be running, eg, Lively Kernel in the client, and writing code in both the client and server and trying them out in real time while everything is running.

My immediate interest is the ability to cobble together a collaboration server for Lively entirely in JavaScript. It should be easy to spawn these nodes like crazy in the cloud if we ever want some scale.

Wednesday, April 21, 2010


We need to fix an anomaly in our alphabet.  Every letter but one has a name of one syllable;  read them off and you will find the guilty party boasting not two, but three syllables to its name.

Yes, it's "double u".  You'd think it would be double-v anyway, but let's not get off topic.  We've let this go on for a long time because W sits so near to the end of the alphabet that we're not thinking of uniformity by the time we get to it, we're just waiting for Z.  Our children's alphabet poem is no help in teaching consistency because it already suffers from such rhythmic irregularities as "elemeno-pee".

Well, the time has come to set things right:

    W, we dub thee "Dub".

Apart form the peace of mind that will come from having an equisyllabic alphabet, think of the savings.  With over a billion Internet users, if each one says "dub dub dub" instead of "double-u double-u double-u" only once a day, it will save us 365 billion seconds each year.  Dude, that's 100 million hours -- more than enough to make up for the time spent building a library for our 43rd president.  Who, by the way, shall henceforth be known simply as "Dub".

Here's a poem to commemorate the event, but I hope someone will do better...

        Friends, though I'd rather not trouble you,
        The time's come to rename our W.
                One syllable per letter
                Would simply be better;
        Let "Dub" be the new name for W

Batteries in the air

We knew that lithium polymer batteries would change the world when this appeared...

If you think it's easy to fly one of these you're wrong -- these guys are good.

But this takes things to a whole new level...

I got this link from Ilmari Heikkinen who is the brains behind CAKE, an impressive animation library built on JavaScript and Canvas graphics.

I had a design years ago for a similar vehicle with 6 rotors powered by chain saw engines.  The control system I had in mind was incredibly simple:  A weight hanging down with cables to each motor so if it tipped in one direction it would increase the throttles on the down side and reduce those on the up side.  I never did build it but, gosh, I do have 4 leaf blowers in the garage left over from the bike...