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Author Topic: How fast do urine splashes travel?  (Read 5422 times)

Offline EvilHomer15

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How fast do urine splashes travel?
« on: 05/05/2012 23:01:43 »
Hello naked scientists.

I was standing, peeing, the other day, when something unexpected happened.
One of the splashes reached the height of my head.
I found this to be very weird, and not theoretically possible.
It would make sense if I peed forcefully, but this was relatively slow-going.

Can anyone explain this to me?
« Last Edit: 18/05/2012 09:56:44 by chris »


 

Offline Don_1

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Re: Physics of urinating.
« Reply #1 on: 05/05/2012 23:54:22 »
I'm not taking the ......... but how tall are you?

Going into a newly redecorated public toilet, I noticed a sign on the wall which read "Wet Paint", underneath, some comical bog wall author had scribbled "This is not an instruction."
 

Offline CliffordK

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Re: Physics of urinating.
« Reply #2 on: 06/05/2012 00:12:23 »
Going into a newly redecorated public toilet, I noticed a sign on the wall which read "Wet Paint", underneath, some comical bog wall author had scribbled "This is not an instruction."
[xx(]

There would be a lot of factors.
Are you going into water, or onto a solid surface.  I would think a solid surface would create better "bounces".
The height of the urinal

Due to a restricted opening, the fire-hose may in fact have liquid exiting at a higher velocity than you would otherwise expect.
 

Offline graham.d

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Re: Physics of urinating.
« Reply #3 on: 06/05/2012 09:22:43 »
I think this topic has been covered before. At least in the general sense and not specifically about peeing. It is certainly possible to create an exit velocity in considerable excess of the incoming velocity when something impacts a fluid. The following paper has a qualitative discussion on the subject but states that the exit velocity can be up to 10 times the entry velocity in certain circumstances...

http://accessscience.com/content/Splashing-drops/YB020855

The reasons are somewhat complicated and depend on several factors. Rest assured that Newton's Laws are still obeyed. The total mass ejected at high speed is much less than the mass entering at low speed. It is just that the fluid can react to the impact in a way that can accelerate a drop of fluid quite significantly. I think a very simple example that may give some insight would be a whip where you can cause the whip-end to exceed the speed of sound without actually moving any solid part of the whip at anything like that speed.
 

Offline Karen W.

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Re: Physics of urinating.
« Reply #4 on: 06/05/2012 13:20:46 »
I'm not taking the ......... but how tall are you?

Going into a newly redecorated public toilet, I noticed a sign on the wall which read "Wet Paint", underneath, some comical bog wall author had scribbled "This is not an instruction."

LOL...LOL..DONT YA JUST LOVE TOILET WRITERS! LOL..HEE HEE HEE....
 

Offline Karen W.

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Re: Physics of urinating.
« Reply #5 on: 06/05/2012 14:38:51 »
Firstly I find this interesting... as being a woman I am quite aware of splash-back having to position myself upon the throne itself... I must say that the velosity of urine is strongly effected by the more or less urgency of the bladders need to empty.. and also the amout of urine that is bearing down against the opening, thus increasing the water pressure so to speak.. For example, I can drink a single glass or cup of coffee and within moments my bladder is urgently behaving like it is so full its going to burst! So upon that urgency or pressing matter, I hustle to the loo assume the position and immediately begin  the elimination, but to my surprise the relief I seek is slow and gradual as the urine seems to be exiting at a rather boringly slow pace in what I expected to be a rushing raging forceful exit of a flooding river which is overtaking its banks and sending water crashing down over rocks  with much force and enough spash-back to be sending water splashing high up over ones head..... The whole emptying seems so much less satisfying then had been  indicated by the powerful erge to eliminate this coffee! Lol...
Now when I have had loads of water, juice, and many glasses of liquid over a longer period of time,  and that sense of urgency comes over me.. and lets say I ignore it or delay the trip to the loo, then my body begins to do the child like potty dance, adult version of course, which involves my teeth floating..lol or feeling like they are floating, and a sudden case of the pee shivers along with the terrible feeling that I am just not going to make it...lol..by the time I arrive, I am feeling like the hunchback of notre dame hunched over trying not to full on let the flood gates go, that when I hit the stool I have already shed the nessasary clothing and am experiencing a very forceful exilerating release of very high pressured urine which is blasting out
in an incredible high pressure jet stream which is furious in nature and
causing a very high splash-back.. which splashes a womans back side making a "bedai"  ( sorry about spelling ) a very lovely invention....lol...
THEREFORE... I recieve this incredible relief and satisfaction with continued spasms of urine being elliminated even after the main empting has subsided.. as if there are small pockets of urine hiding in and about my bladder as if playing hide and seek with the muscles and propulsion
mechanisms in the bladder!.. Thus I believe that more input causes higher
velocity which is also effected by gravity ..increasing the pressure on the bladder opening causing more splatter.  So in my mind and opinion that could cause higher splash....eh?
     
Something else accures to me though. Could passing a kiddney stone cause a higher splash and a more pronounced sound when hitting the toilet bowl or
urinal....?



 
« Last Edit: 06/05/2012 14:48:53 by Karen W. »
 

Offline Geezer

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Re: Physics of urinating.
« Reply #6 on: 06/05/2012 20:06:42 »

One of the splashes reached the height of my head.


That's nuthin. When I was five years old I could elevate the entire stream well above my head. On one occasion we (I can't remember if it was me or someone else) even managed to hit the school janitor's hat.  He was standing in the playground outside the boy's toilet.
 

Offline Pmb

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Re: Physics of urinating.
« Reply #7 on: 06/05/2012 21:56:01 »

One of the splashes reached the height of my head.

That's nuthin. When I was five years old I could elevate the entire stream well above my head. On one occasion we (I can't remember if it was me or someone else) even managed to hit the school janitor's hat.  He was standing in the playground outside the boy's toilet.
I imagine that the energy in the toilet water starts to build up as the drops start hitting the water. Eventually one of the drops will have enough energy to exceed the energy that could be gathered buy a given number of single drops. Simply put, the energies of the single drops keep adding until one gains enough potential energy to reach that height.
 

Offline Karen W.

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Re: Physics of urinating.
« Reply #8 on: 06/05/2012 23:17:01 »
Lol..geezer..no fair..sounds like you were aiming....lol...

PMB...THAT SOUNDS I TERESTING.. I WOULD NEVER HAVE EVEN THOUGHT THAT THE ENERGY OF SINGLE DROPS OF SPLATTER COULD BUILD UP??? I am sorry..about caps..I forgot them..how does a drop or splatter that has already splatted help the following indiviual drops to build momentum?
 

Offline Pmb

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Re: Physics of urinating.
« Reply #9 on: 07/05/2012 00:59:51 »
Lol..geezer..no fair..sounds like you were aiming....lol...

PMB...THAT SOUNDS I TERESTING.. I WOULD NEVER HAVE EVEN THOUGHT THAT THE ENERGY OF SINGLE DROPS OF SPLATTER COULD BUILD UP??? I am sorry..about caps..I forgot them..how does a drop or splatter that has already splatted help the following indiviual drops to build momentum?
Picture it in your mind. The first drop transferes some energy to the fluid. So when there was no energy now there is some. Now add another drop etc. the energy of the fluid eventuall builds up until a few drops can transfere some energy to a drop which can attain a potential energy large enough so that the drop attains eye level. If it happens at all. If he said it did then it must have happen. Here we have to rely on someone's word as far as whether a drop reachd that height.
 

Offline Karen W.

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Re: Physics of urinating.
« Reply #10 on: 07/05/2012 02:18:38 »
So the drop or stream is hitting the water making waves creating energy..so i might understand that the wave dispells the water while more urination continues to dispell the water until perhaps the urine actually hits the bowl itself and causes a splash back that spatters higher then his heigth correct...? At the same time displacing so much more urine or fluid than the original impact.. therefore the splatter....
 

Offline graham.d

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Re: Physics of urinating.
« Reply #11 on: 07/05/2012 09:44:55 »

One of the splashes reached the height of my head.


That's nuthin. When I was five years old I could elevate the entire stream well above my head. On one occasion we (I can't remember if it was me or someone else) even managed to hit the school janitor's hat.  He was standing in the playground outside the boy's toilet.

So it was you, Geezer. When at primary school ALL the boys in the school were caned because nobody owned up to this particular act - at least it was rumoured that this was the crime as the headmaster was too much of a prude to actually say what it was. This was an injustice and in some ways affected my way of thinking for life, and probably not in the way the sadist headmaster had in mind.
 

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Re: Physics of urinating.
« Reply #11 on: 07/05/2012 09:44:55 »

 

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