[ ]   [ ]   [ ]                        [ ]      [ ]   [ ]

Climate Change - R_P - Jul 14, 2025 - 12:42pm
 
But Why? - Proclivities - Jul 14, 2025 - 12:36pm
 
NYTimes Connections - Proclivities - Jul 14, 2025 - 12:11pm
 
The Marie Antoinette Moment... - R_P - Jul 14, 2025 - 11:35am
 
Wordle - daily game - marko86 - Jul 14, 2025 - 11:19am
 
Artificial Intelligence - R_P - Jul 14, 2025 - 11:16am
 
NY Times Strands - GeneP59 - Jul 14, 2025 - 10:59am
 
Fox Spews - R_P - Jul 14, 2025 - 10:52am
 
What is the meaning of this? - rgio - Jul 14, 2025 - 10:44am
 
Radio Paradise Comments - GeneP59 - Jul 14, 2025 - 10:36am
 
Fascism In America - Red_Dragon - Jul 14, 2025 - 9:59am
 
260,000 Posts in one thread? - oldviolin - Jul 14, 2025 - 8:40am
 
Name My Band - oldviolin - Jul 14, 2025 - 8:37am
 
Trump - rgio - Jul 14, 2025 - 8:33am
 
• • • The Once-a-Day • • •  - oldviolin - Jul 14, 2025 - 8:04am
 
Why atheists swallow, - black321 - Jul 14, 2025 - 8:00am
 
USA! USA! USA! - ColdMiser - Jul 14, 2025 - 7:57am
 
On Life as Art- heard it on KTRT 95.7 - KurtfromLaQuinta - Jul 14, 2025 - 7:56am
 
Comics! - KurtfromLaQuinta - Jul 14, 2025 - 7:53am
 
Music Videos - black321 - Jul 14, 2025 - 7:51am
 
Economix - black321 - Jul 14, 2025 - 7:11am
 
Beyond mix - ericb - Jul 14, 2025 - 7:01am
 
Today in History - Red_Dragon - Jul 14, 2025 - 6:31am
 
July 2025 Photo Theme - Stone - NoEnzLefttoSplit - Jul 14, 2025 - 3:05am
 
Great Old Songs You Rarely Hear Anymore - buddy - Jul 13, 2025 - 5:49pm
 
M.A.G.A. - R_P - Jul 13, 2025 - 3:53pm
 
Are they married yet? YES THEY ARE! - KurtfromLaQuinta - Jul 13, 2025 - 3:16pm
 
Israel - R_P - Jul 13, 2025 - 1:15pm
 
Baseball, anyone? - kcar - Jul 13, 2025 - 12:41pm
 
Infinite cat - Isabeau - Jul 13, 2025 - 11:37am
 
Dialing 1-800-Manbird - oldviolin - Jul 13, 2025 - 11:35am
 
What Makes You Laugh? - GeneP59 - Jul 13, 2025 - 10:10am
 
Talk Behind Their Backs Forum - VV - Jul 12, 2025 - 9:16pm
 
What the hell OV? - oldviolin - Jul 12, 2025 - 8:39pm
 
Europe - R_P - Jul 12, 2025 - 6:30pm
 
Democratic Party - R_P - Jul 12, 2025 - 1:37pm
 
Bug Reports & Feature Requests - machar - Jul 12, 2025 - 12:34pm
 
A motivational quote - steeler - Jul 11, 2025 - 6:58pm
 
Beyond... - GeneP59 - Jul 11, 2025 - 6:35pm
 
Protest Songs - R_P - Jul 11, 2025 - 12:38pm
 
True Confessions - oldviolin - Jul 11, 2025 - 11:56am
 
Jess Roden - legendary UK vocalist - and "Seven Windows" ... - J_C - Jul 11, 2025 - 11:22am
 
Live Music - oldviolin - Jul 11, 2025 - 10:13am
 
It seemed like a good idea at the time - ptooey - Jul 11, 2025 - 6:10am
 
Country Up The Bumpkin - KurtfromLaQuinta - Jul 10, 2025 - 9:13pm
 
TV shows you watch - R_P - Jul 10, 2025 - 5:31pm
 
Wasted Money - GeneP59 - Jul 10, 2025 - 5:22pm
 
Rock mix / repitition - walk2k - Jul 10, 2025 - 4:31pm
 
How's the weather? - GeneP59 - Jul 10, 2025 - 3:21pm
 
Random Solutions - Random Advice - oldviolin - Jul 10, 2025 - 10:11am
 
Spambags on RP - KurtfromLaQuinta - Jul 10, 2025 - 9:02am
 
misheard lyrics - GeneP59 - Jul 10, 2025 - 6:30am
 
New Song Submissions system - Teja - Jul 10, 2025 - 3:36am
 
TEXAS - Red_Dragon - Jul 9, 2025 - 5:57pm
 
DQ (as in 'Daily Quote') - black321 - Jul 9, 2025 - 11:33am
 
Republican Party - Red_Dragon - Jul 9, 2025 - 7:50am
 
Outstanding Covers - oldviolin - Jul 8, 2025 - 9:29pm
 
Trump Lies™ - R_P - Jul 8, 2025 - 7:14pm
 
Musky Mythology - R_P - Jul 8, 2025 - 5:43pm
 
Photography Forum - Your Own Photos - Alchemist - Jul 8, 2025 - 11:45am
 
Love & Hate - oldviolin - Jul 8, 2025 - 8:15am
 
Anti-War - R_P - Jul 7, 2025 - 6:45pm
 
Environment - R_P - Jul 7, 2025 - 5:38pm
 
(Big) Media Watch - R_P - Jul 7, 2025 - 12:04pm
 
The Grateful Dead - black321 - Jul 7, 2025 - 11:17am
 
Mixtape Culture Club - KurtfromLaQuinta - Jul 7, 2025 - 8:59am
 
Immigration - black321 - Jul 7, 2025 - 8:02am
 
Russia - Red_Dragon - Jul 7, 2025 - 7:39am
 
Triskele and The Grateful Dead - geoff_morphini - Jul 6, 2025 - 10:33pm
 
Hey Baby, It's The 4th O' July - GeneP59 - Jul 6, 2025 - 9:42pm
 
Customize a shirt with my favorite album - 2644364236 - Jul 6, 2025 - 7:20pm
 
Those Lovable Policemen - R_P - Jul 6, 2025 - 10:56am
 
Beer - SeriousLee - Jul 6, 2025 - 6:54am
 
Iran - R_P - Jul 5, 2025 - 9:01pm
 
What are you doing RIGHT NOW? - Coaxial - Jul 5, 2025 - 6:48pm
 
Index » Regional/Local » Elsewhere » Science in the News Page: Previous  1, 2, 3, 4, 5 ... 9, 10, 11  Next
Post to this Topic
Red_Dragon

Red_Dragon Avatar

Location: Gilead


Posted: May 30, 2011 - 7:42pm

 helenofjoy wrote:
This made my face hurt.

 
yes.
jadewahoo

jadewahoo Avatar

Location: Puerto Viejo, Costa Rica
Gender: Male


Posted: May 30, 2011 - 6:55pm

 beamends wrote:

Or coffee.
 
{#Roflol}

beamends

beamends Avatar



Posted: May 30, 2011 - 3:26pm

 oldslabsides wrote:

I bet this makes a wave, too

 

 
Or coffee.

Lazy8

Lazy8 Avatar

Location: The Gallatin Valley of Montana
Gender: Male


Posted: May 30, 2011 - 3:23pm

 helenofjoy wrote:
This made my face hurt.

I forgot to mention: point the knife away from your face!

helenofjoy

helenofjoy Avatar

Location: Lincoln, Nebraska
Gender: Female


Posted: May 30, 2011 - 3:22pm

 Lazy8 wrote:
 oldslabsides wrote:
now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me.

Yes. Shockwaves are a finite thickness, and what you see is the light bending as it passes thru the shockwave. From the side the light passes thru more of the shockwave along the leading surface of the shock than is does behind the leading surface on its way to you, so you see it in profile.

Here's a way to think about it that might help: hold an imaginary half of a pumpkin in your hand with the guts all scooped out. It's a pretty much a uniform thickness. Now imagine you have a long pumpkin-carving knife you can poke thru the pumpkin, and poke it thru near the open end of the pumpkin, all the way across.

It goes thru nearly perpendicular to the outer surface, which penetrates nearly the minimum amount of pumpkin possible while still getting thru both sides. Now poke it thru sideways across the bottom of the pumpkin. Since it goes thru the wall at a shallower angle it goes thru more pumpkin on its way out the other side. Poke it thru low enough and its whole trip thru will be inside the wall of the pumpkin. A ray of light taking that path will see the maximum amount of distortion from the differential index of refraction of the shock wave—not because it spent more time in the different index, but because it had farther to go before its path straightened out again when it reached undisturbed air on the other side.

So rays of light along the leading surface of the shock will appear to show it in cross-section.
  This made my face hurt.


Lazy8

Lazy8 Avatar

Location: The Gallatin Valley of Montana
Gender: Male


Posted: May 30, 2011 - 3:16pm

 oldslabsides wrote:
now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me.

Yes. Shockwaves are a finite thickness, and what you see is the light bending as it passes thru the shockwave. From the side the light passes thru more of the shockwave along the leading surface of the shock than is does behind the leading surface on its way to you, so you see it in profile.

Here's a way to think about it that might help: hold an imaginary half of a pumpkin in your hand with the guts all scooped out. It's a pretty much a uniform thickness. Now imagine you have a long pumpkin-carving knife you can poke thru the pumpkin, and poke it thru near the open end of the pumpkin, all the way across.

It goes thru nearly perpendicular to the outer surface, which penetrates nearly the minimum amount of pumpkin possible while still getting thru both sides. Now poke it thru sideways across the bottom of the pumpkin. Since it goes thru the wall at a shallower angle it goes thru more pumpkin on its way out the other side. Poke it thru low enough and its whole trip thru will be inside the wall of the pumpkin. A ray of light taking that path will see the maximum amount of distortion from the differential index of refraction of the shock wave—not because it spent more time in the different index, but because it had farther to go before its path straightened out again when it reached undisturbed air on the other side.

So rays of light along the leading surface of the shock will appear to show it in cross-section.

Red_Dragon

Red_Dragon Avatar

Location: Gilead


Posted: May 30, 2011 - 8:13am

 ptooey wrote:

We're a little short on brass instruments, actually.  I've got 2 guitars, a drum set, a piano, and a harmonica (oh, and I'm expecting a ukulele on Thursday .)  The kids have an accordion and a cello. 
 
I bet this makes a wave, too

 
ptooey

ptooey Avatar

Location: right behind you. no, over there.
Gender: Male


Posted: May 30, 2011 - 8:05am

 NoEnzLefttoSplit wrote:


Yeah, but what about the trombone?

 
We're a little short on brass instruments, actually.  I've got 2 guitars, a drum set, a piano, and a harmonica (oh, and I'm expecting a ukulele on Thursday .)  The kids have an accordion and a cello. 

NoEnzLefttoSplit

NoEnzLefttoSplit Avatar

Gender: Male


Posted: May 30, 2011 - 8:02am

 ptooey wrote:

Yeah, I've got a couple of old scientific surplus catalogs sitting at the house.  I'll check into what they've got.  It really doesn't look all that tough.
 

Yeah, but what about the trombone?
ptooey

ptooey Avatar

Location: right behind you. no, over there.
Gender: Male


Posted: May 30, 2011 - 7:58am

 ScottFromWyoming wrote:

I thought that might be trouble
 
$250 is the price for new. Talk to someone there about what you need: a mirror out of a trashed telescope, it can have some scratches, I doubt that will matter much. 

 
Yeah, I've got a couple of old scientific surplus catalogs sitting at the house.  I'll check into what they've got.  It really doesn't look all that tough.

ScottFromWyoming

ScottFromWyoming Avatar

Location: Powell
Gender: Male


Posted: May 30, 2011 - 7:56am

 ptooey wrote:

Dammit.  Dammit, dammit, dammit. 

*heads off to e-bay*

Edit:  $250 for an 8" mirror.  Ahh.  Nope.
 
I thought that might be trouble
 
$250 is the price for new. Talk to someone there about what you need: a mirror out of a trashed telescope, it can have some scratches, I doubt that will matter much. 
Red_Dragon

Red_Dragon Avatar

Location: Gilead


Posted: May 30, 2011 - 7:47am

 ptooey wrote:

Dammit.  Dammit, dammit, dammit. 

*heads off to e-bay*
 

ptooey

ptooey Avatar

Location: right behind you. no, over there.
Gender: Male


Posted: May 30, 2011 - 7:44am

 ScottFromWyoming wrote: 
Dammit.  Dammit, dammit, dammit. 

*heads off to e-bay*

Edit:  $250 for an 8" mirror.  Ahh.  Nope.

ScottFromWyoming

ScottFromWyoming Avatar

Location: Powell
Gender: Male


Posted: May 30, 2011 - 7:27am

 oldslabsides wrote:
now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me. 
 
The depth of field is so shallow that it essentially is showing you just a cross-section of the half-a-bubble wave. Nearer to or further from the lens is out of focus so it doesn't show up.

Edit: well I was on the right track crack.

Schleiren photography note the link from there to Collimated light

A do-it-yourself guide to Schlieren photography 


NoEnzLefttoSplit

NoEnzLefttoSplit Avatar

Gender: Male


Posted: May 30, 2011 - 6:47am

 oldslabsides wrote:
now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me. 

 

i think its because the wave will travel slower as it propagates out to the sides, kind of like waves turning the corner at the beach, presuming you have a beach with corners, that is..
oldviolin

oldviolin Avatar

Location: esse quam videri
Gender: Male


Posted: May 30, 2011 - 6:41am

 oldslabsides wrote:

yes, but the contact lens has an edge in addition to its convex side...

who said anythin' about hatin'? 

 

But I see the edge. Don't you?
just rattling your cage...
Red_Dragon

Red_Dragon Avatar

Location: Gilead


Posted: May 30, 2011 - 6:36am

 oldviolin wrote:


look at a contact lens from the side...any side, and it's the same. The shock wave is basicallythe same convex shape. maybe...
stop hatin' on peoples horn bones will ya?
 
yes, but the contact lens has an edge in addition to its convex side...

who said anythin' about hatin'? 
beamends

beamends Avatar



Posted: May 30, 2011 - 6:35am

 oldviolin wrote:


look at a contact lens from the side...any side, and it's the same. The shock wave is basicallythe same convex shape. maybe...
stop hatin' on peoples horn bones will ya?


 
or the shock wave from an explosion, wherever you view from it's still dome shaped (in ideal conditions).

oldviolin

oldviolin Avatar

Location: esse quam videri
Gender: Male


Posted: May 30, 2011 - 6:32am

 oldslabsides wrote:
now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me. 

 

look at a contact lens from the side...any side, and it's the same. The shock wave is basicallythe same convex shape. maybe...
stop hatin' on peoples horn bones will ya?

Red_Dragon

Red_Dragon Avatar

Location: Gilead


Posted: May 30, 2011 - 6:19am

now wait a minute...

What if this were filmed from above the trombone?  Or from beneath; would the "shockwave" still be in the shape of an arc?  Something about the perspective here just doesn't seem real to me. 
Page: Previous  1, 2, 3, 4, 5 ... 9, 10, 11  Next