Riddle: What is the first thing you do to turn your bike?

What is the very first thing you do to turn your bicycle or motorcycle?

Counter-intuitive: ask most people what is the first thing they do when making a turn on a bicycle (or motorcycle) and they'll either say "turn the handlebars in the direction I want to go" or "lean in the direction I want to go" - both are wrong.  That's not really what you are doing!

What we are forced to learn as youngsters but rarely realize consciously is that the FIRST action when you want to turn on a two-wheeler is to turn the handlebars in the OPPOSITE direction. This puts you out of balance, causing you to lean in the direction you actually want to go and, by compensating with the handlebars, you initiate your turn. (Look up "counter-steering".)

I didn't learn this until I took a motorcycle safety course with Maria after a lifetime of cross-country riding. I had no idea.

The immediate benefit was that I became 1000% better at dodging potholes: For a quick change in direction, push down on the handlebar on the same side as the direction you want to go - to dodge right, push down on the right hand handlebar.

(Second benefit: great cocktail party riddle.)

Are you teaching a youngster how to ride a bicycle?  IMHO: Teach them counter-steering from the get-go (and ditch the training wheels, they will interfere with understanding how it all works).

P.S. Some folks say, it is POSSIBLE to turn a 2-wheeled vehicle with "handlebar steering" (turning the handlebars in the direction you want to go), but, IF that's true, it's true only if you are creeping along at a very slow speed.  Part of our learning to ride involves learning to counter-steer (frequently unconsciously).

Here are the physics: https://www.youtube.com/watch?v=ZpV2Bg-WX0w

Why are US Phone Numbers 7 digits?

A colleague recently asked me if I hadn't written an EID editor's column about how Al Chapanis had determined that the optimal length of a telephone number was 7 digits. Here is my response:

Dear xyz,
Fascinating question...

This may be the editor's column you remember:
http://musicman.net/EID_Comment-Winter02.pdf

However, the Chapanis work I was referring to wasn't about the number of digits in a phone number, it was about the layout of the keypad.

I have no information, other than the apocryphal anecdotes about Miller's "magic number 7" to explain why telephone numbers are 7 digits long in the U.S.A. (though I suspect the total population of phones in different areas might have something to do with it as well).

I saw several references to some working memory brain theories that affirm, if not explain the convention:
http://prl.aps.org/abstract/PRL/v103/i21/e218101

However, another reference quotes Miller himself as saying:

And finally, what about the magical number seven? What about the seven wonders of the world, the seven seas, the seven deadly sins, the seven daughters of Atlas in the Pleiades, the seven ages of man, the seven levels of hell, the seven primary colors, the seven notes of the musical scale, and the seven days of the week? What about the seven-point rating scale, the seven categories for absolute judgment, the seven objects in the span of attention, and the seven digits in the span of immediate memory? For the present I propose to withhold judgment. Perhaps there is something deep and profound behind all these sevens, something just calling out for us to discover it. But I suspect that it is only a pernicious, Pythagorean coincidence.

It gets messy when you start talking about "chunking". For instance, I don't think I remember phone numbers near my home as 10 digits. When I hear an area code or an exchange that I recognize, introspection tells me that I remember that as a single entity -- I actually sometimes visualize an area (or a mobile coverage map).

Even without chunking, I think the grouping itself is useful (nnn-nnn-nnnn) as a "performance cue". I find I can more easily transcribe a teleconference pin if the calendar host puts in the artificial hyphen (and if the number is 7 digits long -- if it's 8 digits then I start stressing about overseas phone number patterns ;-).

Perhaps it is because I'm a vocal performer, but I find it very comforting to slot arbitrary numbers into the rhythmic pattern neh-neh-NEH neh-NEH-neh-NEH. This is a 4-beat phrase of 7 eighth notes and a trailing whole note with a familiar "polka" emphasis on all but the first primary quarter note beat. (Though for music, I much prefer the jazz-style syncopations.)

Riddle: Why are manhole covers round?

How long are your legs? 

My friends know that I'm willing to come up with a theory for anything. I'm embarrassed to say I was completely stumped when someone asked me to speculate how the bilateral parts in our human bodies "know" to stop growing at the same length/size.

The legs I can imagine because we're constantly pounding on them and I can imagine them "evening out". But the arms? Ears and eyes for that matter? I know that hormones are involved in the cessation of skeletal growth, but that doesn't fully cover it from my limited understanding.

I'll probably look it up eventually.

BTW: Abraham Lincoln was once asked "How long to you think a man's legs should be?"  His answer was "Long enough to reach the ground".

Why are manhole covers round?

Riddle: Say, if you read this far, perhaps you like riddles? Here's one of my favorites: Why are manholes and their covers round? (They weren't always that way, I believe an easier-to-fabricate octagonal shape was favored in the early days.)

Answer: It turns out that a round cover is the only shape that can't fall through it's own hole!  I don't know about you, but I sure wouldn't want to be in a sewer, but if I WAS, I wouldn't want a 300 pound manhole cover falling on my head!