# Water as unyielding as concrete

Discussion in 'Physics & Math' started by Lilalena, May 13, 2011.

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Why is it?

3. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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If the egg is acclerated steadily at a low value (say 1/2 metre/ sec/ sec) then it won't break up due to the "force behind the egg". But, eventually it will reach a speed at which air acts as an unyeilding medium and then break up.
Hence: you're talking bollocks.
You have persistently, as I have pointed out at least twice, conflated breaking up due to accelerative force with breaking up due to aerodynamic resistance.

5. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Wrong. That wasn't the actual question.

7. ### John99BannedBanned

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You have proof of this?

On its own, with no external forces.

8. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Pardon?
Proof of what?
That an egg won't break under low acceleration? Yes.
That it will break up under aerodynamic stresses at high speed? Yes.
Any other questions?

I note, with amusement, that you have failed to offer anything other othe rthan your own (uninformed) assertions, yet you ask if I have proof...

Edit:
What do you mean "no external forces"?

9. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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No I don't...Please explain what you mean.

10. ### John99BannedBanned

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Show me the proof. An egg can be accelerated (artificially) to the point that it breaks immediately and this is why i am telling you that the introduction of external forces renders the experiment null and void.

Otherwise we would wrongly conclude that air is as unyielding as concrete. See the connection?

:wallbang:

11. ### John99BannedBanned

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No, it is all there in the thread.

12. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Proof one: any time at all you move an egg it undergoes acceleration. How often do they break? Do they break when you take one out of the fridge?
Proof two: even steel aircraft break up under aerodynamic stress at high speed.
If necessary you could Google for the strength of an eggshell and work out the speed that will cause it to crack due to air pressure exceeding those structural limits.

Yes. A high acceleration.

Balls.

Last edited: May 31, 2011
13. ### John99BannedBanned

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Seriously dude, you're backed in a corner and you know it. An egg traveling freely through the air, as if dropped, will not break until it hits something. Force the egg (force speed) like fired from a device or thrown too hard (which i have done) and it can break right in the air.

Given that fact the firing of the gun ruins the test. This is not an accurate representation of the water breaking the bullet. That was my only contention and i stand by it.

14. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Wrong.

Also wrong. Do you have any proof?

Bullshit. And once again you use the stupid term "force speed".
And in fact your second part of the sentence directly contradicts the previous claim in this post.

And you're still wrong. Utterly and totally.

15. ### John99BannedBanned

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Why is it a stupid term? You already admitted it mena the same thing as thrust etc.

I already have proven it when i threw an egg and it broke as it was released from my hand. Now was it the air or the force that broke the egg? Answer: it was the force.

16. ### John99BannedBanned

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You wouldnt say "oh, the air is as hard as concrete. Well maybe you would. *scratches head*

17. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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It's a stupid term because it's unnecessarily wordy and there's nothing wrong with using the correct terminology. And I haven't "admitted" that it means the same thing: you claimed it did.

If it broke when it was released (i.e. no longer undergoing acceleration) then it must have been air pressure that broke it.

And, as I have already stated, a slow-enough acceleration will NOT break the egg - but if that acceleration is continued then the speed will become extremely high.

How often did you run the experiment? What measuring equipment did you use? Or are you seriously claiming that a single, unmeasured, unscientific occasion is your "proof"?

In other words you're still spouting bollocks.

18. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Not just me...
http://www.laesieworks.com/ifo/how/Aerodynamic.html

19. ### John99BannedBanned

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The point is we want to know how hard the water is (compared to concrete) not how fast something traveling would break up in a given medium.

As far as the egg, i have seen this quite a few times. The egg gets released from hand and travels around half of a metre and breaks up. The insides stream behind it. This is force speed breaking the egg as opposed to natural speed or free falling. I can simulate free fall in the way it is thrown, once i go above a certain threshold the egg breaks. The bullet is going beyond natural threshold.

20. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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Which, as I stated above, goes to show that it isn't the acceleration that breaks it up, but air resistance. Your "proof" shows you are utterly wrong. Well done.

Nope. If it's left your hand then the only "force" on it is gravity and air resistance. Fail.

Oh, like a high vs. low acceleration you mean? Please read my earlier posts where I stated explicitly that this would be the case.

"Natural threshold"? WTF do you mean by that?

21. ### MacGyver1968Fixin' Shit that Ain't BrokeValued Senior Member

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Dy, I'm confused. It seems that John is stating that an egg traveling through the air can only be broken up by the force that gave it it's acceleration, and not through air resistance? Is that the point he's making...I asked him..but didn't want to explain.

I'm the least qualified member of this board to speak about physics...but even the bottom of the barrel can see he's wrong. As velocity increases the aerodynamic pressure on an object increases exponentially. Right?

22. ### PeteIt's not rocket surgeryRegistered Senior Member

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It was the forces applied by the air. Air pressure = force. The higher the airflow, the higher will be the difference in air pressures around the egg.

So in this case, it doesn't matter so much what force you apply, but what speed the egg is moving through the air.

You can apply a low force for a long time to an egg, and it won't break.

If you apply that same low force or the same time in such a way as to give it a high enough airspeed, it will break.

Here's an easy experiment:
Put an egg in a container. A cup will do.
Have someone take you for a drive.
When you're at speed in a safe place, hold the container out the window and carefully tip the egg out toward the rear of the car.

If the egg breaks, it must be because of the air, right?

23. ### DywyddyrPenguinaciously duckalicious.Valued Senior Member

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That seems to be his claim.

Yup.
And his own example shows he's wrong: as I noted if he'd already let go of the egg then no acceleration applied.
To support his claim that it's the acceleration breaking the egg (which is certainly possible) then it would have to break while still in his hand.

Last edited: May 31, 2011