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I almost get it

I’m seriously innumerate. I’m sure I’ve mentioned that. It’s not something I’m proud of (I hate it when people are proud of being bad at stuff). I have a feeling mathematics encompasses some of the most interesting shit ever, and I’m totally locked out of the party.

But every once in a while — especially when math is expressed in something visual — I allllmost get it.

Take fifteen simple, independent pendulums of graduating lengths. The longest swings back and forth 51 times in 60 seconds. Each successive, shorter pendulum completes one extra back and forth in that same period. Start them all swinging at once with a board thingie, and this is exactly how I imagine it would look. Except that period in the middle when they all go kind of wild-ass and un-wavy.

This has been around the web for a while; I just found it kind of hypnotic to watch.


Comment from Oceania
Time: February 15, 2012, 11:08 pm

Here’s an old one I found


Comment from Alice
Time: February 15, 2012, 11:33 pm


My math abilities are perhaps above average but still sadly rudimentary. I yearn to understand it better. It’s like there is some secret poetry in numbers that I can almost sense but remains always just out of reach of my consciousness.

I get just a little taste of something more each time I read E.T. Bell’s fantastic “Men of Mathematics”. Amazon description “Men of Mathematics accessibly explains the major mathematics, from the geometry of the Greeks through Newton’s calculus and on to the laws of probability, symbolic logic, and the fourth dimension. In addition, the book goes beyond pure mathematics to present a series of engrossing biographies of the great mathematicians — an extraordinary number of whom lived bizarre or unusual lives. Finally, Men of Mathematics is also a history of ideas, tracing the majestic development of mathematical thought from ancient times to the twentieth century. This enduring work’s clear, often humorous way of dealing with complex ideas makes it an ideal book for the non-mathematician.”
Highly recommended.

Comment from Nina
Time: February 15, 2012, 11:42 pm

Wow! Awesome!

I’m a math idiot, too, Stoaty. And I feel the same way about it that you do. It pisses me off that someone as smart as I am can’t figure it out.

Anyway, this is going on FB right now!

Comment from Redd
Time: February 15, 2012, 11:43 pm

Cool! So, what’s the mathematical explanation for this: http://goo.gl/WkUj1

Comment from Kilroy182
Time: February 15, 2012, 11:47 pm

“Mathematics is the language with which God has written the universe.” – Galileo Galilei

Comment from Malcolm Kirkpatrick
Time: February 16, 2012, 12:10 am

“I’m seriously innumerate.”
Thass’ okay. I teach math and I can’t read music or play an instrument. I’ll clear a room if I try to sing and I can’t even draw an acceptable cartoon cat.

Comment from Mrs. Compton
Time: February 16, 2012, 12:11 am

I’m sorry, wha…. you lost me at 60 seconds.

Comment from Uncle Badger
Time: February 16, 2012, 12:19 am

That’s what I like about Stoaty’s blog.

One day it’s romance novels. The next swinging balls.

Oh, but wait…

Comment from Alice
Time: February 16, 2012, 12:35 am

Nice video, Redd. Thanks!

Comment from Redd
Time: February 16, 2012, 1:40 am

Nice video, Redd. Thanks!

You’re welcome. Here’s another: http://goo.gl/HFTti

I have never seen this before and I’m not sure what would cause it (besides eating a delicious puppy chow meal).

Comment from JeffS
Time: February 16, 2012, 2:28 am

Cool! While a college student studying to be a civil engineer, simple harmonics were of great interest to us — they are HIGHLY destructive to structures, especially bridges. The study of “Galloping Gertie“, a/k/a Tacoma Narrows Bridge, used to be mandatory back when, especially when considering the environment in your designs.

And as a soldier, I learned a quick way to destroy a bridge: march a battalion of troops across one in cadence. The synchronized slamming of boots against the deck can be enough to put the bridge into simple harmonic motion. Not a good thing.

Of course, as a college student, I also learned about what the student body called “simple seduced harmonic motion”. But that’s a different story.

Comment from Feynmangroupie
Time: February 16, 2012, 2:31 am


It has to do with Cute-um Mechanics. The forced being exerted by the gravitational(g) pull of earth multiplied by 1/2 the mass of the puppy(m) and the force of the puppy’s cuteness(q) causes the puppy’s front legs to act as a fulcrum, upon which the forward momentum multiplied by puppy enthusiasm^(n-1/2) = angular momentum of the puppy as it eats it’s meal. (where n=years of age).

Comment from Alice
Time: February 16, 2012, 2:42 am

Wow – More fun with center-of-gravity tricks!

Comment from Tibby
Time: February 16, 2012, 2:50 am

Now that was seriously cool! Like you, I can’t do the math, but I can intuit it. Wish I could explain that, but that isn’t gonna happen either. Anyway, I’m sharing on FB too! Too much fun not to.

Comment from Oceania
Time: February 16, 2012, 4:09 am

This just in….

Time-Life, Inc. is about to start shooting the documentary about Whitney Houston.

Samuel L. Jackson was offered the title role.

“And I will always loooove you… muhfugga”

Comment from David Gillies
Time: February 16, 2012, 4:21 am

This turned out to be trivially easy to simulate in Mathematica. It’s just an ensemble of uncoupled oscillators, and pendulums (for small displacements) make pretty good simple harmonic oscillators, which are sinusoids. For pendulum i, i = 1…15, amplitude A and initial phase φ, the displacement x as a function of time x(t) = A cos(2 π (50 + i) t/60 + φ). I chose A = 1 and φ = π/6 = 30° and fed it into Mathematica’s Animate[] function. Worked like a charm. I should probably export it as a Quicktime movie and post it on YouTube.

For those of you with Mathematica:

x[A_, \[Omega]_, \[Phi]_, t_] := A Cos[\[Omega] t + \[Phi]]

Point[{x[1, 2 \[Pi] (50 + i)/60, \[Pi]/6, t], i/10}]}, {i, 1,
15}], AspectRatio -> 0.8, PlotRange -> {{-2, 2}, {0, 1.6}}], {t,
0, 60, 0.0002}, AnimationRate -> 0.5, AnimationRunning -> False]

If these were coupled oscillators the behaviour would be much harder to model. You’d need to solve the eigensystem and I haven’t done that since first year vibrations and waves class in ’89. You’d start seeing chaotic behaviour for certain values of the coupling, I’d bet.

Comment from Oceania
Time: February 16, 2012, 4:25 am

Whoever sockpupetteted me at 0409 hrs can listen to “my hair’s falling out”


Comment from Redd
Time: February 16, 2012, 1:51 pm

It has to do with Cute-um Mechanics.

The best and most scientific explanation evah!

Comment from sandman says:nothing to see here…
Time: February 16, 2012, 8:30 pm

Seems the Diesel Depot called…you left your knee pads in the parking lot and a trail leading away from the scene…rather like a slug. The Depot says your priviliges are suspended until further notice.
The drag queen at the cash register also suggested a tic tac for ya.

that is all.

Comment from Oceania
Time: February 17, 2012, 2:30 am

Sockpuppetted? WTF is that? It isn’t even a word!
If you silly Americans wish to impersonate me, then you are going to have to use Kiwi words.
Otherwise you are all over the place like a mad woman’s piss at a BBQ.

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