OT: Things we find freaking neat but no place to post

[forty_three]

Constitution Day Materials, US Constitution, Pocket Constitution Book, Declaration of Independence, Bill of Rights

I particularly like this one:
1916: all acts of war should be put to a national vote. Anyone voting yes had to register as a volunteer for service in the United States Army

 

[Nasty_Magician]

 

[forty_three]

6 Castles that cost less than an apartment in NYC? - Imgur

 

[dash]

Milt Stegall ‏@MiltStegallTSN You know you live in the south when it's 27F/-3C windy, no snow or ice and schools are closed. SOFT #onlyinthesouth

 

[forty_three]

 

[mattola]

I did it. Ive reached 1000 KMS (I actually reached this just before Christmas but it was not recorded but Ill go by the recording)... My first run I did was Mar 19th 2013 2.33 km in 22 mins I thought I was going to die. My longest Run was 16.11 km in 2hrs and I had to stop myself from running. Now I have had 132 runs in 9 1/2 months for 1007 KMs. I love running

 

[forty_three]

I did it. Ive reached 1000 KMS (I actually reached this just before Christmas but it was not recorded but Ill go by the recording)... My first run I did was Mar 19th 2013 2.33 km in 22 mins I thought I was going to die. My longest Run was 16.11 km in 2hrs and I had to stop myself from running. Now I have had 132 runs in 9 1/2 months for 1007 KMs. I love running

Congrats.

Those apps are pretty sweet. You never really realize how far you really go. This past summer I got to almost 700mi on my bike.

 

[forty_three]

R.A. Dickey knuckle ball, colorized to highlight lack of spin.

 

[Darkstone42]

R.A. Dickey knuckle ball, colorized to highlight lack of spin.

Whoever that catcher is, terrible pitch receiving.

Two major errors: he reached for a ball for which he didn't need to reach, and he shifted his body away from the center of the plate. You are a lot less likely to get strike calls doing those things.

But the colorizing, very cool.

 

[Nasty_Magician]

 

[dare2be]

I always wanted to hear from a fluid dynamics expert why a ball with no spin has such an erratic flight path.

 

[forty_three]

I always wanted to hear from a fluid dynamics expert why a ball with no spin has such an erratic flight path.

I've always understood it that the air currents are unstable (somewhat like an airplane bouncing from gust to gust), but the spin of a non-knuckleball stabilizes the ball kind of like a gyroscope.

Whether it's true or not is another story.

 

[dare2be]

So, the spinning ball creates its own pocket of stable pressure gradient and air current bubble to protect it, kind of like a warp field. I knew Star Trek had something to do with it...

 

[jstewismybastardson]

Whoever that catcher is, terrible pitch receiving.

Two major errors: he reached for a ball for which he didn't need to reach, and he shifted his body away from the center of the plate. You are a lot less likely to get strike calls doing those things.

But the colorizing, very cool.

but you have to admit ... he closed his eyes using great technique lol (look closely)

 

[dash]

but you have to admit ... he closed his eyes using great technique lol (look closely)

I closed my eyes quite a bit when R.A. Dickey was on the mound as well this past season - When I opened them, I quite often saw a batter rounding the bases.

 

[jstewismybastardson]

I closed my eyes quite a bit when R.A. Dickey was on the mound as well this past season - When I opened them, I quite often saw a batter rounding the bases.

read that in penthouse forum once back in the day

 

[Comeds]

read that in penthouse forum once back in the day

I think I did too, I never thought of the Mudville Nine" the same way again.

 

[dash]

I put 'em on the tee, jstew and comeds knock 'em out of the park (lol)

 

[Darkstone42]

I always wanted to hear from a fluid dynamics expert why a ball with no spin has such an erratic flight path.

BEHOLD!

Knuckleball Research

In essence, spin provides a force to the ball. Fastball spin makes the ball rise, which is why they look straight (it counteracts gravity). Knuckleballs are subject to air-induced forces and seam forces because it has no spin forces. These are less consistent, so the ball's path becomes erratic from pitch to pitch.

 

[Darkstone42]

BEHOLD!

Knuckleball Research

In essence, spin provides a force to the ball. Fastball spin makes the ball rise, which is why they look straight (it counteracts gravity). Knuckleballs are subject to air-induced forces and seam forces because it has no spin forces. These are less consistent, so the ball's path becomes erratic from pitch to pitch.

Having reviewed one of the papers in some detail, here is the explanation:

Lift occurs in the direction of the nearest seam. Fastballs, on average, have the nearest seam fixed in one spot due to rotation around it, with all other orientations averaged out due to rapid rotation, so they lift straight. Knuckleballs rotate slowly, so the direction changes. Throwing a knuckleball with a two-seam orientation puts these changes in direction temporally closer together. Some orientations of knuckleball, however, do not move unpredictably, which is why knuckleballers occasionally look like they're throwing batting practice. They basically are.

The drop of a properly executed knuckleball can change mid-flight. It can start out flat, drop sharply about halfway to the plate, then flatten out a bit again when it gets to the batter.