brainwagon

Last night’s reading reminded me that I have never really been satisfied with my understanding of how siphons work. Apparently I’m not the only one, since there was this interesting exchange on Straight Dope which pointed out some of the disconcerting issues that surround explanations of their actions. I’m still not convinced I have a good understanding of their action. For example, in the cartoon above, it implies that air pressure pushes down on the tank above, but surely it also applies to the water below in the bucket, yes? I’m guess I’m skeptical about this “air pressure” idea. Tom suggested briefly in lunch that as long as the fluid’s vapor pressure was such that the weight of the downward column was insufficient to introduce cavitation, that the siphon action would continue. That sounds more like the truth to me, since it doesn’t rely on any notion of “atmospheric pressure” pushing on things. But I’m still not 100% satisfied with my understanding.

via The Straight Dope: How does a siphon work?.

Addendum: Wikipedia has a nice article, including some helpful math.

I’ve been interested in hydroponics for quite some time. It’s part of a growing interest that I have in sustainable and decentralized production of food and energy. At the Maker’s Faire, there was a display of a system which integrated both hydroponics and aquaculture: fish were grown in a tank, whose water circulated back to water some plants. This is called “aquaponics”. Digging around on the Internet this evening (hey, I was bored) yielded this excellent manual on a beginning system that uses a series of barrels. It seems very practical, and answers many interesting questions. The total amount of food produced is quite small, but the overall system is quite interesting. I’ll have to print it out and read up.

Faith and Sustainable Technology -- The Barrel-Ponics Manual.

Addendum: Here’s a little Youtube video detailing a system built by an amateur. It uses goldfish and carp fingerlings, and he is growing tomatoes and other vegetables and flowers.

Okay, before I get too excited, I’ll disclose that Cake was set to a time limit of around 1 second, which limited it to just a few ply (maybe 9 typically) and I was letting MIlhouse think a little harder (still taking less than 10 seconds typically). Still, it’s good: it means that sparring matches between milhouse and cake can be tuned to make them challenging. I need to figure out how I can build milhouse as an engine for CheckerBoard so this can be automated.

Perhaps I could use mingw to build an appropriate dll.

[Event "Morning Match"]
[Date "2009-05-04"]
[Black "Cake, 1sec per move"]
[White "Milhouse, 19 ply search"]
[Result "0-1"]
1. 9-13 23-19 2. 6-9 27-23 3. 11-15 23-18 4. 8-11 26-23 5. 4-8 30-26 6. 9-14 18x9 7. 5x14
22-18 8. 15x22 25x9 9. 11-16 9-6 10. 2x9 24-20 11. 8-11 26-22 12. 10-15 19x10 13. 7x14
29-25 14. 16-19 23x7 15. 3x10 28-24 16. 10-15 32-28 17. 14-18 24-19 18. 15x24 22x15 19.
9-14 28x19 20. 14-18 15-10 21. 12-16 19x12 22. 13-17 21x14 23. 18-22 25x18 24. 1-5 31-27
25. 5-9 14x5 0-1

Wow…. this is the 3000th post that I’ve made to my blog since it’s inception. Huzzah.

I really need to get a hobby.

In any case, Bill Meara over at the Soldersmoke blog mentioned this video about constructing solar cells from donuts and tea.

It sounds like a joke, but it’s not. It turns out that powdered donuts aren’t just white because they have powdered sugar on them, but because they also contain titanium dioxide. Who knew? You can read about them on Wikipedia.

Earlier, I blogged about the collision between Iridium 33 and the defunct COSMOS 2251 satellite. Today, I noticed that Celestrak had orbital elements for 134 fragments resulting from the collision. I was curious what the resulting pattern would look like, so I wrote a bit of code to suck them all in and plot them on a map. Here’s what I got for a particular moment around noon local time.

The labeled points are the tracked location of the main body of the satellite. There are orbital elements for 48 additional fragments of Iridium, and 84 additional fragments of COSMOS. The main body of Iridium 33 was at 785km altitude, while Cosmos is down around 771km. Debris is scattered over quite a wide variety of altitudes, from a low of 284km to a high of 1158km.

You can find some occasionally surprising stuff on youtube. I’d seen a number of videos illustrating rapid crystallization of supersaturated mixtures of sodium acetate, but this is something a little different that I hadn’t seen before. Does anyone know what’s really going on here?

P.S. It’s “iodized” salt, not “ionized”.

Courtesy of hack-a-day, check out the following video illustrating an analog computer that implements the dynamics of a bouncing ball, not using a microprocessor, but just a circuit involving analog operational amplifiers.

Bouncing ball analog computer -- Hack a Day.

Thanks to Joanne, K9JKM for pointing out that Space Weather Radio is piping audio of Ursid Meteors crossing the radar fence which guards our country from the Ruskies. If you tune in, occasionally you’ll hear a rapid descending tone, caused by the radar bouncing off the ionized trails of meteors. Pretty cool.

This is the craziest bit of science that I’ve seen in quite a while.

Sticky Tape X-rays

Via hack-a-day, here is a link on creating your own ferrofluids. My first exposure to these was as part of the SIGGRAPH art show a few years back, check them out on Google video.

[tags]Ferrofluid,Science[/tags]

Most often when I link to someone else’s blog, it is because a particular article has tweaked some small bit of my interest.  These blog entries are often isolated, and the blogs that I link to often have a high noise to signal ratio.  It is therefore with some pleasure that I recommend Red State Rabble for your consumption.  It is the work of Pat Hayes, a writer who lives in Kansas and directly addresses some of the silliness surrounding the current “debate” over Intelligent Design.   In addition to being something of continuing interest to me, he’s a good writer with many good insights.  It joins The Panda’s Thumb on my blogroll under daily reads.

[tags]Science,Evolution,Creationism,Intelligent Design[/tags]

This is just too cool! Need to make a few million nanoscale smiley faces?

Rothemund has developed a computer program that can analyze a shape, figure out the right folding pattern, and then tell you what DNA staples you need to make that shape.”It’s really easy and fun, actually, to make whatever you want at the nano-scale. You design it in the computer, you order the DNA sequences, they come in the mail, you add a little bit of salt water, you heat it up and cool it down, and then an hour and a half later, it’s ready to look at under the microscope.”

[tags]DNA,Science,NPR[/tags]

Carmen noticed that the Google home page had a logo that included a telescope looking at Mars.   A moment’s digging revealed that there is a new version of Google Maps called  Google Mars. Now everyone can view VallesMarineris and Olympus Mons.  Cool stuff.
[tags]Mars,Google Maps[/tags]

A few minutes ago, I noticed the second minor earthquake of the day. I estimated the strength to be a little lower than a three, but it was enough that my next door neighbor Sam called me and asked me what I thought it was. I was already hitting the USGS website to see what the deal was, but he reminded me that you can get even faster realtime info from a finger server at berkeley:

% finger -l quake@quake.geo.berkeley.edu
[quake.geo.berkeley.edu]
Login name: quake                       In real life: EQs? USE finger -l
Directory: /home/dc1/quake              Shell: /bin/csh
Never logged in.
No unread mail
Plan:

RAPID EARTHQUAKE LOCATION SERVICE
U.S. Geological Survey, Menlo Park, California.
U.C. Berkeley Seismological Laboratory, Berkeley, California.
(members of the Council of the National Seismic System)

NOTE:  Information in this page is updated regularly.  If you are accessing
this page via the Web, you may need to RELOAD the page to get current data.

Below is a list of magnitude 2 or greater earthquakes recorded by the USGS
Northern California Seismic Network and the UCB Berkeley Digital Seismic
Network during the last 3 days.  All times are in UTC (Universal Time),
which is 8 hours ahead of PST and 7 hours ahead of PDT.  This catalog is
valid for Central and Northern California (approximately north of San Luis
Obispo along the coast and 37 degrees N at the Nevada border).

Magnitudes are reported as local magnitude (Ml) or coda duration magnitude
(Md) for small events.  Depth is in kilometers.  Q is location quality,
where the quality of the location solution is A=E (A=good, E=bad), and '*'
indicates the solution is from an automated system and has not been reviewed
by staff.

Note:  This is PRELIMINARY information.  Earthquakes before 00:00 UT today
which occur > ~50 km outside the boundaries of the network will not be
listed unless reviewed by seismologists.

Catalogs for other regions of the country can be obtained by using
`finger quake@computer'  for the following computers:
geophys.washington.edu (Washington and Oregon)
seismo.unr.edu  (Nevada)         scec.gps.caltech.edu (southern California)
eqinfo.seis.utah.edu (Utah)      fm.gi.alaska.edu (Alaska)
slueas.slu.edu (central US)      gldfs.cr.usgs.gov (large world-wide)
tako.wr.usgs.gov (Hawaii)

WWW access: for these lists, maps, and more go to http://quake.usgs.gov

Updated at Thu Mar  2 06:32:00 GMT 2006 a.k.a. Wed Mar  1 22:32:00 PST 2006

******************************************************************************

DATE-(UTC)-TIME   LAT    LON      DEP   MAG  Q  COMMENTS
yy/mm/dd hh:mm:ss   deg.   deg.    km
------------------------------------------------------------------------------
06/02/27 13:55:31  40.08N 123.49W   0.0 2.0Md C*  29 km E of  Redway, CA
06/02/27 14:24:41  39.72N 123.07W   2.0 2.1Md C*  19 km ESE of  Covelo, CA
06/02/27 16:43:04  37.27N 120.75W   0.5 2.2Md D*  13 km S of  Livingston, CA
06/02/27 20:46:44  36.50N 121.07W   3.6 2.3Md A*   7 km ESE of  Pinnacles, CA
06/02/28 01:09:55  39.01N 122.80W   2.6 2.4Md B*   5 km NNE of  Kelseyville, CA
06/02/28 03:32:42  35.67N 121.08W   0.0 2.2Md D*  10 km ENE of  San Simeon, CA
06/02/28 03:52:50  38.82N 122.80W   1.9 2.0Md A*   3 km N of  The Geysers, CA
06/02/28 19:39:39  37.86N 122.24W   9.5 2.3Md A*   3 km ESE of  Berkeley, CA
06/03/01 19:24:02  37.86N 122.20W   8.9 2.8Md A*   4 km SW of  Orinda, CA
06/03/01 19:34:52  37.86N 122.20W   8.8 3.4Ml A*   3 km SW of  Orinda, CA
06/03/02 00:11:55  36.55N 121.15W   7.6 3.2Ml A*   3 km N of  Pinnacles, CA
06/03/02 02:11:37  37.16N 121.55W   8.1 2.1Md A*   9 km ENE of  Morgan Hill, CA
06/03/02 04:53:30  40.48N 125.53W   2.5 3.3Ml D* 106 km W of  Petrolia, CA
06/03/02 05:11:11  38.36N 119.43W   1.1 2.1Md C*  20 km WNW of  Bridgeport, CA
06/03/02 06:08:15  37.86N 122.24W   9.8 2.9Md A*   3 km ESE of  Berkeley, CA

I just thought I’d archive that here for future reference.

[tags]Earthquake,Earthquake Server[/tags]

We don’t get much snow here, but I thought I might archive this for future reference, just because it’s cool.

Save a Snowflake for Decades – Popular Science

1. Set microscope slides, coverslips and superglue outside when it’s 20°F or colder to chill them. Catch flakes on the slides or pick them up with cold tweezers.
2. Place a drop of superglue on the snowflake. Note: Gel glue doesn’t work. Find a brand that’s thin and runny.
3. Drop a coverslip over the glue. Don’t press down hard or the flake could tear or melt from the heat of your finger.
4. Leave the slide in a freezer for one or two weeks and don’t touch it with warm hands. The glue must completely harden before the snowflake warms up.