Why Does Oil stick to steel better than water?: Philosophy Forums

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Why Does Oil stick to steel better than water?
can anyone help me answer this?

Why Does Oil stick to steel better than water?

jimRH7
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Posted 03/22/08 - 07:08 AM: Subject: Why Does Oil stick to steel better than water?	#1
hullo, I'm doing an essay on separation techniques in the oil industry, and i came across this machine, http://www.oliveoilsource.com/scripts/dictionary.... I was wondering if anyone could tell me WHy oil stick to steel better than the water?

rabeldin
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Posted 03/22/08 - 05:55 PM:	#2
Read up on surface tension to get started.
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jimRH7
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Posted 03/23/08 - 07:08 AM:	#3
well, I understand a bit about surface tension, what I don't understand is why it makes the oil stick to the metal better than the water.

smd42
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Posted 03/23/08 - 10:27 PM:	#4
Hello! I'm new here. And I like this question. First, you should understand the two forces of attraction (between molecules). INTER-molecular forces and INTRA-molecular forces. Intra-molecular forces - attractive forces that hold particles together with ionic, covalent, and metallic bonds. An example might be the bond which holds a spinning electron around a helium atom. Inter-molecular forces - attractive forces among or between particles, called dispersion forces, dipole-dipole forces, and hydrogen bonds. -Dispersion: results from a temporary shift in the density of electrons in the electron cloud. Like, when an atom loses or gains an electron. \|\|dispersion = nonpolar\|\| -Dipole: attractions of oppositely charged regions of polar molecules. north-south (of a magnet) or positive-negative. Think: Opposites Attract! \|\|dipole-dipole forces = polar\|\| -Hydrogen Bonds: When Hydrogen bonds with Fluorine, Nitrogen, or Oxygen. (really it�s when hydrogen bonds with very electronegative atoms with a lone pair of electrons. ) Example: H20 or WATER!! These bonds are really the base of chemistry. They are basically what make everything happen. Okay. Now Hydrogen is the strongest and Dispersion is the weakest of the intermolecular forces. So it you have a liquid with Hydrogen bonds, it�s going to have strong bonds holding it together. So that means that water sticks to itself. This is called... cohesion! That's why when it rains there are little droplets of water everywhere. Mercury is crazy. I can�t remember the exact number, but I think it�s seven times more cohesive than water. The most cohesive element on the periodic table. But what about OIL, right? Well, it's the opposite. It is very adhesive. This means that it doesn't stick to itself very well at all. It just spreads around whatever its surface is. Oil is non polar, meaning that the forces that hold oil together are dispersion. The weakest force. Think about washing your hands. If you wash your hands with just water, it's easy to dry them. The water, which is polar and has strong attractive bonds, forms droplets which can be easily absorbed by a towel or such an object. Now think about washing you hands with oil, non polar, and weakly attracted to itself. It just sticks to your hands! I hope that this makes sense. I've got to go now, but if you have questions, I'll answer them. Oh crap, surface tension! Yeah well, that's just the relationship of cohesion versus adhesion of a liquid. More adhesion, less surface tension; more cohesion more surface tension. Edited by Postmodern Beatnik on 03/24/08 - 07:15 AM. Reason: minor issues
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jimRH7
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Posted 03/24/08 - 07:29 AM:	#5
hullo smd42! well, I underastand that it is caused by surface tension, but i don't understand HOW it is caused by surface tension. Anyone, PLEASE! Edited by jimRH7 on 03/25/08 - 11:07 AM

smd42
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Posted 03/27/08 - 07:13 PM:	#6
Surface tension is caused by bonds. The stronger the bond, the more surface tension.
_____________________ He felt that his whole life was some kind of dream and he sometimes wondered whose it was and whether they were enjoying it. There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

smd42
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Posted 03/27/08 - 07:15 PM:	#7
Try to visual this when you think of the intermolecular bonds. http://hyperphysics.phy-astr.gsu.edu/hbase/fluids...
_____________________ He felt that his whole life was some kind of dream and he sometimes wondered whose it was and whether they were enjoying it. There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

smd42
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Posted 03/27/08 - 07:18 PM:	#8
Here's a website for more info, but it basically states what I already said. Still, it might make more sense with the pictures. http://images.google.com/imgres?imgurl=http://hyp...
_____________________ He felt that his whole life was some kind of dream and he sometimes wondered whose it was and whether they were enjoying it. There is a theory which states that if ever anybody discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

jimRH7
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Posted 04/02/08 - 09:58 AM:	#9
I understand surface tension, but how does the oil stick to the Metal? that's what i don't understand.

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