You are sitting in a canoe, in a swimming pool, holding a cannon ball in 
your lap. You throw the cannonball overboard, and it sinks to the 
bottom. Does the level of water in the pool go up, go down, or stay the 
same?

(I've asked this of probably a dozen or more scuba dive instructors, and 
only one has gotten it right. The reasoning behind the correct answer is 
obvious once you hear it. I don't remember if I got it right when I 
heard it.)

-- 
   Darren New / San Diego, CA, USA (PST)
     It's not feature creep if you put it
     at the end and adjust the release date.

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Is the canoe traveling near the speed of light?

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> Is the canoe traveling near the speed of light?
> 

I lol'd.

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Darren New wrote:
> You are sitting in a canoe, in a swimming pool, holding a cannon ball in 
> your lap. You throw the cannonball overboard, and it sinks to the 
> bottom. Does the level of water in the pool go up, go down, or stay the 
> same?

The water goes up (then down again) in a mostly parabolic manner since 
the bowling ball would make a large splash :-)

I won't spoil the real answer for anyone still thinking about it, but 
here's another fun physical puzzle that I remember:

If you've been on the beach, you've probably noticed that the sand dries 
out around you foot when you step on it, why is this?  Wouldn't you 
expect a small puddle of water to form around your foot instead?

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"Darren New" <dne### [at] sanrrcom> wrote in message
news:477ad72c$1@news.povray.org...
> You are sitting in a canoe, in a swimming pool, holding a cannon ball in
> your lap. You throw the cannonball overboard, and it sinks to the
> bottom. Does the level of water in the pool go up, go down, or stay the
> same?

I believe it should stay the same.

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In article <477b1419@news.povray.org>, wampler+pov### [at] uwashingtonedu 
says...
> Darren New wrote:
> > You are sitting in a canoe, in a swimming pool, holding a cannon ball i
n 
> > your lap. You throw the cannonball overboard, and it sinks to the 
> > bottom. Does the level of water in the pool go up, go down, or stay the
 
> > same?
> 
> The water goes up (then down again) in a mostly parabolic manner since 
> the bowling ball would make a large splash :-)
> 
> I won't spoil the real answer for anyone still thinking about it, but 
> here's another fun physical puzzle that I remember:
> 
> If you've been on the beach, you've probably noticed that the sand dries
 
> out around you foot when you step on it, why is this?  Wouldn't you 
> expect a small puddle of water to form around your foot instead?
> 
It does get wetter, just *outside* the range of displacement from the 
pressure you apply to the sand. And, if you stand there long enough that 
the grains can rearrange to be less compacted, you *will* end up with 
your puddle.

-- 
void main () {

    if version = "Vista" {
      call slow_by_half();
      call DRM_everything();
    }
    call functional_code();
  }
  else
    call crash_windows();
}

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3D Content, and 3D Software at DAZ3D!</A>

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Gail Shaw wrote:
> "Darren New" <dne### [at] sanrrcom> wrote in message
> news:477ad72c$1@news.povray.org...
>> You are sitting in a canoe, in a swimming pool, holding a cannon ball in
>> your lap. You throw the cannonball overboard, and it sinks to the
>> bottom. Does the level of water in the pool go up, go down, or stay the
>> same?
> 
> I believe it should stay the same.
> 
> 

Incorrect.  Hint - The cannon ball sinks to the bottom.  Think about 
what was preventing it doing so before.

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Patrick Elliott wrote:
> It does get wetter, just *outside* the range of displacement from the 
> pressure you apply to the sand. And, if you stand there long enough that 
> the grains can rearrange to be less compacted, you *will* end up with 
> your puddle.

Indeed, but that doesn't really explain why it dries out initially. 
Contrast it with stepping in wet mud for example, or on a wet carpet. 
(as far as I understand the phenomenon, by the way, I believe that your 
explanation of why the puddle eventually forms is incorrect).

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Darren New <dne### [at] sanrrcom> wrote:
> You are sitting in a canoe, in a swimming pool, holding a cannon ball in 
> your lap. You throw the cannonball overboard, and it sinks to the 
> bottom. Does the level of water in the pool go up, go down, or stay the 
> same?

  A classic.

  The answer can be deduced by thinking about volume and weight.

  In the canoe the ball displaces an amount of water proportional to
the weight of the ball. In the water it displaces an amount proportional
to the volume of the ball.

  So the question is basically reduced to: Which is denser, the cannonball
or water?

-- 
                                                          - Warp

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Warp wrote:

> Darren New <dne### [at] sanrrcom> wrote:

>   So the question is basically reduced to: Which is denser, the cannonball
> or water?
> 


That's where I was headed. Does the cannonball displace more
water "underwater" than in the boat, and the difference being
volume*(DENSITYcannonball-DENSITYwater)/DENSITYwater?

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