Good question! The repelling forces are less than the attracting forces. This is because of distance. Coulombs Law states that the force between 2 electrical charges is proportional to the square of the distance between them. The unshared electrons of an oxygen atom are farther from the unshared electrons of its neighbor (repulsion) than the partial positive of the hydrogen(attraction). So the attractive force is greater. Really good question. Think Mole!
Does this make sense? The distance for repulsion and attraction depends largely on the arrangement or orientation of water moleculars. How do we know which is farther?
in order to minimize the potential energy of the system (for stabilization), they form a spherical surface so that minimum water molecules with high energy remain at the surface. For a given volume, sphere has minimum surface area, therefore they form spherical bubbles.
Thanks for the explanation, but I had a small comment in mind. The charges on the hydrogen and oxygen on water are not positive and negative, but are rather partial charges. That's all I guess
Thanks for the great guide. Do you think temperature has an effect on surface tension? (Btw, the water molecule's charges can be explained through electronegativity, the O is more electronegative therefore it pulls the electrons towards it giving it a partial negative charge :p)
Hey, can you tell me if my reasoning is correct? This is about the "smoking bottle" trick. When you twist the bottle, the pressure increases and there is a higher rate of vaporation. However, no visible vapor is seen yet because the bottle is a closed container and whatever H2O does vaporize condenses back into liquid form. Then, when you quickly open the bottle, you expose the water inside to the atmospheric pressure. At a short moment, the atmospheric pressure is less then the vapor pressure of the bottle. Thus, the vapor pressure can overcome the atmospheric pressure's force and the water boils, creating a thick cloud inside the bottle.
Hi. Thanks for the video. I am having difficulty in understating a inference and would much appreciate your help. I understand that, for molecules in the surface, there is no unbalanced force in the horizontal direction but only in the vertical direction, with a net force towards the inside of the bulk. But what I don't understand is, why because of unbalanced force in vertical direction, there is a tensile force in the horizontal direction, i.e. surface tension?
KeerthiVasan Rajamani ...surface molecules will tend to "lay flat" on the surface. They form a surface network. This gives the surface the horizontal force.
Thank for the explanation but I have a question, you mentioned that in the space shuttle, where their is little gravity the water formed large bubble, so dont you think that in the earth where the gravity is great, it what makes the mlcs to come down and not up
That is a great question. Remember that surface tension pulls the surface "in" and not necessarily "down". Have you ever made a bubble of water on a penny? Try it. On the "sides" of the bubble, there is a force from surface tension pulling the surface molecules "in" to the bubble that is perpendicular to the force of gravity. Wish I could draw you a pic. Best Wishes.
Thanx for the great explaination Sir! I would like to know if we consider a substance whose molecules have no net dipole moment so will its surface molecules not experience surface tension ?
+Shakti Saxena That is a good question. A substance like CCl4 (nonpolar) will experience surface tension due to van der Waals attractions. I would anticipate that the surface tensions of these substances to be rather low.
If a very strong, reversed polarity electrostatic beam was applied to iron. Could the van der Waals force repel the iron molecules from iron molecules?
Hey water is covalent bond so there is sharing of electron between aH2 and O2 which means there is no gurantee that O is always negative and H always positive sometimes they can be neutral.{ Correct me if I am wrong.}
+Madhab Koirala You are correct. The e's are shared and spend "most of their time" near the oxygen. But there is a small chance that they will be near the hydrogen causing it to be negative and the oxygen to be more positive! However e move so fast that this situation is very brief so we tend to ignore it. (Think quantum mechanics) Thanks for the question.
Hey mr J! Great video I just got a quick question My office school's exterior is made up of glass and is currently being cleaned I noticed that the CLEANED glass windows are forming more water droplets than the UNCLEANED glass windows. Why do you think that is? and do you think you can point me to any references/links that can explain this phenomenon. I've been researching about cohesion and adhesion but have not really seen a precise explanation for it.
Cool observation! Something like that would go right past many people. You have a keen eye. I really don't know but I could make a guess. It could be that the "grime" that builds up on the surface of the glass is acting like a "surfactant" and is breaking the surface tension of the water. This would cause the water on the window to be more sheet-like instead of drop-like. Try rubbing some dirty glass with a clean cloth and try to test to see if it has surfactant properties. Let me know if you try it. God bless.
The systolic pressure in a major artery is measured at 115 mmHg. What is the net force on a 1 cm2 section of the arterial wall if the (absolute) pressure in the tissue outside the arterial wall is 109 kPa? (Patm = 101.3 kPa) Answer: 0.76 N
Nice explanation - thank you. But then what do surface tension reducers do? I work in the oil & gas industry and we try to reduce the surface tension of water/ or other fluids (not sure) in wells. Thanks again!
Great question! This is an explanation for high school students. If you would like a more in-depth explanation check this one: ua-cam.com/video/iElz6l1E8fc/v-deo.html
Please look at the following document Why is surface tension a force parallel to the interface? Antonin Marchand Joost H. Weijs and Jacco H. Snoeijer Bruno Andreotti A paperclip can float on water. Drops of mercury do not spread on a surface. These capillary phenomena are macroscopic manifestations of molecular interactions and can be explained in terms of surface tension. We address several conceptual questions that are often encountered when teaching capillarity and provide a perspective that reconciles the macroscopic viewpoints from thermodynamics and fluid mechanics and the microscopic perspective from statistical physics. VC 2011 American Association of Physics Teachers. [DOI: 10.1119/1.3619866] Mehmet
Why is the area around the Hydrogen positive and the area around the Oxygen negative if they are a covalent bond so they both pull on the same electrons?
Oliver Carlson Thanks for the question. Yes, the bond is covalent; but not 100%. It is polar covalent because of the difference in electronegativity between the H and the O. This causes the shared e's to spend more time around the O. Thus the O has a slight - charge and the H has a slight +. In addition. The O has unshared e pairs.
Sat 007 I know that increasing the temp will decrease the surface tension. I'm guessing that the increase in kinetic energy of the surface molecules allows them to more easily break the weak Intermolecular attraction which cause surface tension. IHTH God bless.
Hi bcubed72, If you are interested in the Reynold's number I will refer you to wikipedia. It has a page dedicated to the subject. en.wikipedia.org/wiki/Reynolds_number
That is an excellent question. I had not considered the effect of temperature. I do not know the answer. My guess is that when the water gets warm, other factors such as vapor pressure would affect the surface.
so the surface layer of molecules feel net force towards the bulk of liquid, then why is it possible to balance the needle on top of it? to me, it would be more intuitive if surface layer had positive upward force (away from bulk of liquid) so that it would cancel with weight of needle, please explain
Interesting idea! Do you have a mechanism for this outward/upward force? Concerning the needle... In order for the needle to sink it has to break through the surface layer. The stronger the lateral bonds in the surface layer the more difficult it will be for an object to penetrate. Think of a fishing net laid horizontal. Toss a light ball onto the net. The net holds up the ball because of the lateral (tension) forces of the net. Now lets say that we toss a cannon ball onto the net. The cannon ball may break through the net. But what is breaking? It is the lateral (tension) forces of the horizontal strings in the net. I hope this helps. GB
Hay! if I get a work surface and wipe it with a silicon or oil base liquid and then poor some water on it, the water will bead and separate, any idea on what I can use to have the opposite effect? I want to get water to totally stick to or totally saturate a large glass marble however at the moment the water is beading up? Any help would be appreciated. Thanks
as far as i know hydrogen molecule has one positive charge which has already connected/attracted to oxygen molecule(balanced] so where does extra charges from hydrogen molecule comes from !!!! Mr.J ....Please help
A huge inaccuracy when you mentioned space shuttle. It is not that there is very low gravity in space shuttle, it is that there is centrifugal force acting against gravitational force. It is a detail, sure, but this misconception is way too common.
+Adam Španěl Do you say that the sun rises or sets? Would you consider yourself perpetuating a misconception for doing so? The problem is that there is no other easy way to describe the situation. Even NASA refers to the gravitational conditions on the space shuttle as "microgravity." Something to consider. God Bless.
It is all about the context. If I am talking casually, of course I say that sun rises and sets and that there is no gravity in a space shuttle, but if I am talking scientifically and technically, I think a bit bigger level of accuracy is needed. I'd probably actually say that "Earth is rotating around its axis exposing different parts of surface to light emitted by sun" or something like that and I would consider it inaccurate to say that sun rises and sets in that context. And microgravity is really just a fancy name for free fall. It is permanent when an object is orbiting earth. Nothing particularly complicated.
+chand basha Good question! The repelling forces are less than the attracting forces. This is because of distance. Coulombs Law states that the force between 2 electrical charges is proportional to the square of the distance between them. The unshared electrons of an oxygen atom are farther from the unshared electrons of its neighbor (repulsion) than the partial positive of the hydrogen(attraction). So the attractive force is greater. Really good question. Think Mole! (Sorry I didn't link this to your question earlier. I posted my response but didn't think to link it to your q. I'm an old dog trying to learn new tricks)
Actually this explanation is not exactly correct. This explanation leads to pressure jump for a flat free surface. However, according to Young Laplace equation the pressure jump is zero. Actually the surface tension is a tension force in tangential direction, not in normal direction. This is due to higher attraction force in tangential force just next to the free surface.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
Excellent drawing art suitable for explaination
Superb depiction...great
such a good explanation. now i can understand it clearly.thank you
The best explanation I've found so far !
You completely explained it well like everything we need to know.
Thanks
sir,it was a great lecture and easy to understand thank you very much!
Good question! The repelling forces are less than the attracting forces. This is because of distance. Coulombs Law states that the force between 2 electrical charges is proportional to the square of the distance between them. The unshared electrons of an oxygen atom are farther from the unshared electrons of its neighbor (repulsion) than the partial positive of the hydrogen(attraction). So the attractive force is greater. Really good question. Think Mole!
Does this make sense? The distance for repulsion and attraction depends largely on the arrangement or orientation of water moleculars. How do we know which is farther?
Mr. J. is this the reason for formation of spherical rain drops??
Thank you so much!!! I have a test on ST and could never figure it out... You explained it so well
I really liked the way you explained it , i got it right away. Thank you :)
well explained ..
what a nice explanation!
Thank you sir great explanation, may Allah bless you
Thank you, Friend.
Excellent explanation!!
great explanation MR.J
5:06 but why would the surface molecules being pulled downwards cause a "skin" on the surface?
Great explanation , thank you vey much
excellent explanation, makes sense now, Thanks
thank u so much Mr.J
hey man, I like the way you explain and breakdown things into simple elements and make everything way easier to understand. I aprreciate your video
Great explanations, thank you!!
Thanks alot..
it is really helpful.
thank u .your explanation was very helpful
so helpful thanks
great viduo
great
Thanks man ! God bless
in order to minimize the potential energy of the system (for stabilization), they form a spherical surface so that minimum water molecules with high energy remain at the surface. For a given volume, sphere has minimum surface area, therefore they form spherical bubbles.
Thanks for the explanation, but I had a small comment in mind. The charges on the hydrogen and oxygen on water are not positive and negative, but are rather partial charges. That's all I guess
So, what is the direction of surface tension force? Is it downwards the liquid , or tangential to the surface (as text books say)?
thank you! it helps me to understand better bout the formation of surface tension.
Thanks for the great guide. Do you think temperature has an effect on surface tension? (Btw, the water molecule's charges can be explained through electronegativity, the O is more electronegative therefore it pulls the electrons towards it giving it a partial negative charge :p)
Hey, can you tell me if my reasoning is correct?
This is about the "smoking bottle" trick. When you twist the bottle, the pressure increases and there is a higher rate of vaporation. However, no visible vapor is seen yet because the bottle is a closed container and whatever H2O does vaporize condenses back into liquid form.
Then, when you quickly open the bottle, you expose the water inside to the atmospheric pressure. At a short moment, the atmospheric pressure is less then the vapor pressure of the bottle. Thus, the vapor pressure can overcome the atmospheric pressure's force and the water boils, creating a thick cloud inside the bottle.
Hi Billy, Are you referring to this demonstration? ua-cam.com/video/VMt7mAUSdBM/v-deo.html
Thank you!! This was a great explanation!
Hi. Thanks for the video. I am having difficulty in understating a inference and would much appreciate your help. I understand that, for molecules in the surface, there is no unbalanced force in the horizontal direction but only in the vertical direction, with a net force towards the inside of the bulk. But what I don't understand is, why because of unbalanced force in vertical direction, there is a tensile force in the horizontal direction, i.e. surface tension?
KeerthiVasan Rajamani ...surface molecules will tend to "lay flat" on the surface. They form a surface network. This gives the surface the horizontal force.
Thank for the explanation but I have a question, you mentioned that in the space shuttle, where their is little gravity the water formed large bubble, so dont you think that in the earth where the gravity is great, it what makes the mlcs to come down and not up
That is a great question. Remember that surface tension pulls the surface "in" and not necessarily "down". Have you ever made a bubble of water on a penny? Try it. On the "sides" of the bubble, there is a force from surface tension pulling the surface molecules "in" to the bubble that is perpendicular to the force of gravity. Wish I could draw you a pic. Best Wishes.
Thanks Mr. J :-)
Vijay Kumar Your welcome. God Bless.
Thanx for the great explaination Sir!
I would like to know if we consider a substance whose molecules have no net dipole moment so will its surface molecules not experience surface tension ?
+Shakti Saxena That is a good question. A substance like CCl4 (nonpolar) will experience surface tension due to van der Waals attractions. I would anticipate that the surface tensions of these substances to be rather low.
If a very strong, reversed polarity electrostatic beam was applied to iron. Could the van der Waals force repel the iron molecules from iron molecules?
I've watched a few videos on surface tension. This was the easiest to understand. Thanks.
thanks Mr.J..Now plese expalin how it's formula came out to be =force/length
nice graphic demonstrating the forces on a single water molecule
thanks Mr.J, do you have explanation about surfactant?
what about the repelling forces in water and what does it happen to them
Hey water is covalent bond so there is sharing of electron between aH2 and O2 which means there is no gurantee that O is always negative and H always positive sometimes they can be neutral.{ Correct me if I am wrong.}
+Madhab Koirala You are correct. The e's are shared and spend "most of their time" near the oxygen. But there is a small chance that they will be near the hydrogen causing it to be negative and the oxygen to be more positive! However e move so fast that this situation is very brief so we tend to ignore it. (Think quantum mechanics) Thanks for the question.
Hey mr J! Great video
I just got a quick question
My office school's exterior is made up of glass and is currently being cleaned
I noticed that the CLEANED glass windows are forming more water droplets than the UNCLEANED glass windows. Why do you think that is? and do you think you can point me to any references/links that can explain this phenomenon.
I've been researching about cohesion and adhesion but have not really seen a precise explanation for it.
Cool observation! Something like that would go right past many people. You have a keen eye.
I really don't know but I could make a guess. It could be that the "grime" that builds up on the surface of the glass is acting like a "surfactant" and is breaking the surface tension of the water. This would cause the water on the window to be more sheet-like instead of drop-like. Try rubbing some dirty glass with a clean cloth and try to test to see if it has surfactant properties. Let me know if you try it. God bless.
Helpful
water is not charged, the atoms are "partially" charged the oxygen atom just pulls the electrons closer to him
+The Bruntje Thanks for the clarification.
lol
The term for this is polarity.
Thank you a lot sir!
Thank you! This helped so much!
Awesome.
thats really nice!
I thought there was partial negative and positive charge in O and H due to covalent bond.( correct me if i am wrong)
+Madhab Koirala You are correct.
Would Plasma activate water mover quicker in capillary action?
The systolic pressure in a major artery is measured at
115 mmHg. What is the net force on a 1 cm2
section of the arterial
wall if the (absolute) pressure in the tissue outside the arterial
wall is 109 kPa? (Patm = 101.3 kPa) Answer: 0.76 N
you have helped me 🌸🌸
That makes my happy. God bless.
6:20, I think you mean a sphere, not a circle.
Don't let a typo or a insignificant error stop you from learning
Patrick Moloney just trying to help...
Nice explanation - thank you.
But then what do surface tension reducers do?
I work in the oil & gas industry and we try to reduce the surface tension of water/ or other fluids (not sure) in wells. Thanks again!
To reduce that interfacial tension between oil and water we uses the surfactants
loooove it
if there is only downward force on the water molecule then why does the molecule does not accalerate downwards on its own
Great question! This is an explanation for high school students. If you would like a more in-depth explanation check this one: ua-cam.com/video/iElz6l1E8fc/v-deo.html
Basically, thanks to attraction, the water becomes a solid body (solid surface, to be specific). Right?
thnq so much for making this video
why at the end the upper surface of water becomes spherical?? water was in a container which was rectangular in the previous page...
Thank you for ur help:)
Thanks a ton!
is surface tension perpendicular or parallel to the surface ?!
Thank you so much
Thanks a lot!!
Please look at the following document
Why is surface tension a force parallel to the interface?
Antonin Marchand
Joost H. Weijs and Jacco H. Snoeijer
Bruno Andreotti
A paperclip can float on water. Drops of mercury do not spread on a surface. These capillary
phenomena are macroscopic manifestations of molecular interactions and can be explained
in terms of surface tension. We address several conceptual questions that are often encountered
when teaching capillarity and provide a perspective that reconciles the macroscopic viewpoints
from thermodynamics and fluid mechanics and the microscopic perspective from statistical
physics. VC 2011 American Association of Physics Teachers.
[DOI: 10.1119/1.3619866]
Mehmet
Why is the area around the Hydrogen positive and the area around the Oxygen negative if they are a covalent bond so they both pull on the same electrons?
Oliver Carlson Thanks for the question. Yes, the bond is covalent; but not 100%. It is polar covalent because of the difference in electronegativity between the H and the O. This causes the shared e's to spend more time around the O. Thus the O has a slight - charge and the H has a slight +. In addition. The O has unshared e pairs.
Great explanation. Took my college professor over an hour and still didn't get it.
Sir will u please elaborate that What's the effect of temperature on surface tension?
Sir it's really needed.
Sat 007 I know that increasing the temp will decrease the surface tension. I'm guessing that the increase in kinetic energy of the surface molecules allows them to more easily break the weak Intermolecular attraction which cause surface tension. IHTH God bless.
you shall use some extra light, for making it little bright
+vivek rajhoria I hope that this was helpful to you. GB.
yes it was!!
How does liquid tend to rise in a capillary?
Does this tie in at all with Reynold's number? Is RN the reason a bug can walk on water, but I can't?
Hi bcubed72, If you are interested in the Reynold's number I will refer you to wikipedia. It has a page dedicated to the subject. en.wikipedia.org/wiki/Reynolds_number
Please tell me something...if the water is warm,, does it mean the surface tension will break easier or harder vs. cold water?
That is an excellent question. I had not considered the effect of temperature. I do not know the answer. My guess is that when the water gets warm, other factors such as vapor pressure would affect the surface.
so the surface layer of molecules feel net force towards the bulk of liquid, then why is it possible to balance the needle on top of it? to me, it would be more intuitive if surface layer had positive upward force (away from bulk of liquid) so that it would cancel with weight of needle, please explain
Interesting idea! Do you have a mechanism for this outward/upward force? Concerning the needle... In order for the needle to sink it has to break through the surface layer. The stronger the lateral bonds in the surface layer the more difficult it will be for an object to penetrate. Think of a fishing net laid horizontal. Toss a light ball onto the net. The net holds up the ball because of the lateral (tension) forces of the net. Now lets say that we toss a cannon ball onto the net. The cannon ball may break through the net. But what is breaking? It is the lateral (tension) forces of the horizontal strings in the net. I hope this helps. GB
Thank you so much :)
thank you but what the deferent betwen T.s in the water and in the tensioactif
Sorry, I am not familiar with "tensioactif."
is there a difference between surface tension and spreading pressure?
+Shirohige Sorry, friend. I do not know the answer to that question.
Hay! if I get a work surface and wipe it with a silicon or oil base liquid and then poor some water on it, the water will bead and separate, any idea on what I can use to have the opposite effect? I want to get water to totally stick to or totally saturate a large glass marble however at the moment the water is beading up? Any help would be appreciated. Thanks
tony wright Hi Tony, if you want a surface to "wet" instead of having the water bead, try some detergent or other surfactant.
how did you make this video? which camera you used?
probably just used my camera phone. I think I taped my phone to a laboratory stand. It has been a while and I cant remember exactly.
Doesn't the gravity also helps .Please explain how gravity affects surface tension
the liquid always takes the shape of the container but how it acquire minimum surface area in surface tension/?
liquid will only take minimum surface area in zero gravity.
as far as i know hydrogen molecule has one positive charge which has already connected/attracted to oxygen molecule(balanced] so where does extra charges from hydrogen molecule comes from !!!! Mr.J ....Please help
The other positive charges come from nearby water molecules. They form what is called a "hydrogen bond". Try looking up videos for "hydrogen bond".
Thanks Mr J
Of corse! Thankyou very much. Fairy liquid did the trick. Thanks
A huge inaccuracy when you mentioned space shuttle. It is not that there is very low gravity in space shuttle, it is that there is centrifugal force acting against gravitational force. It is a detail, sure, but this misconception is way too common.
+Adam Španěl Do you say that the sun rises or sets? Would you consider yourself perpetuating a misconception for doing so? The problem is that there is no other easy way to describe the situation. Even NASA refers to the gravitational conditions on the space shuttle as "microgravity." Something to consider. God Bless.
It is all about the context. If I am talking casually, of course I say that sun rises and sets and that there is no gravity in a space shuttle, but if I am talking scientifically and technically, I think a bit bigger level of accuracy is needed. I'd probably actually say that "Earth is rotating around its axis exposing different parts of surface to light emitted by sun" or something like that and I would consider it inaccurate to say that sun rises and sets in that context.
And microgravity is really just a fancy name for free fall. It is permanent when an object is orbiting earth. Nothing particularly complicated.
Lol the water molecules look like fidget spinners.
That's cool
sir please send me the reason clearly. I cannot understand
+chand basha Good question! The repelling forces are less than the attracting
forces. This is because of distance. Coulombs Law states that the
force between 2 electrical charges is proportional to the square of the
distance between them. The unshared electrons of an oxygen atom are
farther from the unshared electrons of its neighbor (repulsion) than
the partial positive of the hydrogen(attraction). So the attractive
force is greater. Really good question. Think Mole! (Sorry I didn't link this to your question earlier. I posted my response but didn't think to link it to your q. I'm an old dog trying to learn new tricks)
+Mr. J. i wish if that if French
they don't attract each other due to charges
Science is cool
What if water had no surface tension?
then u r living in a other dimension
Summer break and I was curious about surface tension and he tells me I have to right it down!?!?!?! Nooooooo
Stamp Fanatic lol the joke is doing any sort of school work over summer break
:) i got that, was jst kidding
Stamp Fanatic ah
molecules are nurtal
Actually this explanation is not exactly correct. This explanation leads to pressure jump for a flat free surface. However, according to Young Laplace equation the pressure jump is zero. Actually the surface tension is a tension force in tangential direction, not in normal direction. This is due to higher attraction force in tangential force just next to the free surface.
Mehmet Sahin what is pressure jump actually ???
This is actually easy
Globes
Not very accurate in your vocabulary, but good course overall ...