Friday, October 25, 2013 Filed in: Friday Surprise!
One of the interesting things about a video camera is the effect its sequential shutter has on moving objects. A video (or a movie) is a collection of still frames played back rapidly enough that your visual system doesn't detect the gaps between the images. Each image is a slice of time, but when those slices don't match the movement of an object you get some interesting effects. (Ever watch a video of a moving car where the wheels look like they're turning backwards? That's a good example of the phenomenon.
One experimenter took it a step further. He attached a hose to a speaker, which when fed with a continuous tone caused the end of the tube to vibrate. When water flowed through the tube, it was moved back and forth at the same rate as the tube. By varying the frequency (pitch) of the tone being sent through the speakers, he could vary the rate at which the stream of water was deflected.
Here's the cool part: if he matched the frequency (in hertz) to the frame rate of a video camera, he could make the water look like it was hanging in mid-air! Even better, by varying the frequency of the tone even by a single hertz, he could get the water to appear to flow backwards.
Watch and be fascinated.
-=[ Grant ]=-
Friday, March 15, 2013 Filed in: Friday Surprise!
Many of you know my background in watch & clockmaking. People who’ve met me might not think the avocation fits my personality, but in reality it does. As a youngster (heck, even as an oldster) my view of the universe was conceptually very much like that of Aristotle: ordered, unchanging. No, I didn’t believe in crystal spheres, but I did have a rather linear view of things; chaos, in the entropic sense, was something foreign to my existence. Watches and clocks are perfect instruments if you’re into an ordered universe.
It wasn’t until high school, when a physics teacher explained Lorenz Time Transformations, did I start to understand that time was not what I thought it was.
Then came the space-time continuum. Some of the ideas were so conceptually difficult that I think a bunch of my brain cells - the more regimented ones - committed suicide rather than have their view of the universe turned inside-out. I’m not alone, as I’ve discovered; many people have trouble getting their heads wrapped around the topic.
I recently read an article about a “mathemusician” named Vi Hart. She has a unique way of explaining complex topics that’s resulted in a rather rabid YouTube following. If you’re a music or math geek, and particularly if you’re an educator, you should check out her videos.
She recently did a video on the topic of space-time. The theoretical physicists in the audience (don’t laugh, I know of at least one) will point out that what she’s demonstrating isn’t exactly space-time, but she’s got a neat method to get you into the frame of mind where you can start to understand the underlying concept.
(Oh, Stan Kenton recorded a terrific chart by composer Hank Levy titled “Of Space And Time”, from whence this post gets its title. Sadly I couldn’t find a decent rendition of the tune, for free, on the ‘net. You can, however, download it from both Amazon and the iTunes Music Store.)
-=[ Grant ]=-
Friday, March 01, 2013 Filed in: Friday Surprise!
Think about this: the galaxy in which our solar system resides is the Milky Way galaxy. In our own galaxy are more than 200 billion (yes, with a 'b') stars, and scientists estimate there are at least that many planets in and amongst those stars. So, let's just round that off to 400 billion.
In our own galaxy. And, as it happens, there are at least 43,000 more galaxies in the universe.
At least, 43,000 that we can see. Who knows how many galaxies exist that we can't see.
In other words, the fact that the Burger King clerk screwed up your drive-through order really doesn't amount to much in the scheme of things. How's that for perspective?
Still, it would be nice to be able to get around the universe if we could ever leave our own galaxy, and to that end scientists have produced the first 3D map of our universe. (Well, the universe we know about of course.)
Pretty cool, huh? Somewhere out there is the possibility of a planet where they've never heard of "Jersey Shore".
-=[ Grant ]=-
There is a strong tendency in the world of shooting to apply concepts and techniques from the military to private sector self defense. I've written about this concept of context mismatch before, and the upshot is that it almost always works poorly. Just because the military uses guns and we carry guns doesn't make the two worlds analogous!
One of those misapplications is the work of Colonel John Boyd, particularly his OODA Loop (also called Boyd's Loop or Boyd's Cycle.) There are a lot of scholarly works on his theories which I'll leave the uninitiated to discover on their own, but the OODA Loop has been applied to everything from fighter dogfights to football teams - along with defensive shooting.
The issue is that it's not a good fit. A defensive response to a criminal attack doesn't allow for the kind of maneuver-to-advantage thinking that the Loop covers. "Getting inside your opponent's Loop" sounds great and tacticool as all get-out, but when an encounter's duration is measured in seconds that's simply not realistic.
Some years back I started an email conversation with Rob Pincus, who at the time I didn't know but whose writing had impressed me. I was then studying the ideas of stimulus-response and their application to defensive shooting, and over the next few years - first by email and then in person - we talked about that. Rob, like I, was convinced that application of the OODA Loop was incorrect in the context of private sector self defense and the criminal ambush attack. As his understanding of the brain's processing of information and how it uses pattern recognition to make non-cognitive decisions grew, he evolved a different way of looking at the subject.
He just wrote a new paper called "Evolution of the OODA Loop", and it's a highly recommended read. (There's a ton of background information from the world of neuroscience that's implicit in his conclusions, and if you're interested in a readable layman's introduction to some of the topics, I suggest the book "Blink' by Malcolm Gladwell.)
-=[ Grant ]=-
When I was growing up, one of the foremost research labs in the country (and the world) was Bell Labs in New Jersey. They had all the cool toys to play with, and a large amount of both pure science and technological research was being done there. The Bell Laboratories logo was a familiar one to science geeks like me.
When the Bell System was broken up by the government in 1984, Bell Laboratories became AT&T Bell Laboratories. That didn't have any effect on the quantity (or quality) of work coming out of the Labs, and even the mid-90s spinoff of the Labs into Lucent Technologies - with AT&T retaining some of the best staff for themselves - didn't stop their progress.
A complete list of all of the innovations that came from the Labs would fill a book, but just the stuff most of us know is impressive: the C programming language, cel phones, UNIX, modern solar cells, radio astronomy, wireless LANs, and more came from the fertile minds at the Labs.
Sadly, an eighty-three year legacy of top flight research ended in 2008 when the new owners - the French communications conglomerate Alcatel - decided that things like basic science and material physics were not remunerative enough and dismantled most of what remained of Bell's history. Today what's left focuses only on things that can be commercially exploited in a rapid manner. What was once a shining example of American leadership in the hard sciences was reduced to a 'profit center' of an offshore corporation.
It was a phenomenal run though. Luckily the AT&T archives contain a number of videos that the Labs produced over the years to help educate the next crop of American scientists and engineers. I remember seeing some of these when I was in school, and they always fascinated me.
You can peruse them yourself, but I'll start with one of my favorites: "A Sense of Hearing", which begins with a ultra-cool demonstration in what was once the world's quietest room - using a revolver, of course!
-=[ Grant ]=-
I have a geeky confession: my name is Grant, and I'm an amateur radio operator. (Yes, I do have a grid dip oscillator -- and I'm not afraid to use it!)
I mention this because this week I experienced one of the more interesting phenomenon of radio propagation: tropospheric ducting. This happens when a VHF or UHF signal, which is normally limited to line-of-site communication, is bent by a temperature inversion in the troposphere and is able to travel much greater distances than usual. In this particular case, it was nearly 300 miles from my house up to the other fellow's location in northern Washington.
'Tropo', as it's known amongst hams, isn't all that rare but it is a lot of fun. It usually happens in the summertime, especially near the coast where I am. Normally when conditions are favorable I can't find anyone who is also on frequency, and it was simple chance that I happened to be listening to the radio this last week when I heard the other party calling for a contact. When I got a chance to check the current Hepburn tropo forecast map for that day, sure enough conditions were favorable between our two locations.
Ducting isn’t limited to the ham radio bands. Television and radio broadcasts, in fact any wireless transmission in the 50 mhz and up range, can potentially be affected by tropo.
One of the fun parts of ham radio is learning about, and exploiting, atmospheric conditions. It's a little like sailing, I think, where you learn to use the air to take you places. In this case, I use the air to put me in contact with people I don't know but who share my fascination with radio waves.
Now, where did I put that 440mhz Yagi...
-=[ Grant ]=-