Surface Tension of Water Explained

Surface tension in liquid water resists an external force because of cohesive nature (due to hydrogen bonding) of its molecules. Water molecules on the surface of water differ in that they can make fewer hydrogen bonds than water molecules at the center of the liquid. As a result the water molecules are more strongly attracted, and surface tension is present.
Resources:
Hydrogen Bonding Explained: • Hydrogen Bonding in Water
Polar and Non-Polar Molecules Explained: • Polar, Non-Polar, and ...
Surface tension is a common occurrence and of great biological importance (see www.usgs.gov/special-topic/wa....
You can demonstrate surface tension by floating a paperclip on water (see • Make a Paper Clip or C... )
Surface Tension Diagram: commons.wikimedia.org/wiki/Fi...
Water Strider Image: commons.wikimedia.org/wiki/Fi...
Space Station and Water Surface Tension: • 4K Video of Colorful L...

[@sushiman3817]

Woke up at 3 am with a sudden curiosity on how this worked

[@rayanmg6752]

Great videos dr. B. Your videos helped me score 99.1 out of 100 in high school chemistry. I have Graduated from high school a couple of weeks ago.

[@wbreslyn]

Awesome, that is most encouraging! Sounds like you have a bright future ahead.

[@lightcapmath2777]

I ditto the other comments. 3-D modeling and clear explanation keeps me wanting to watch each and every video you create.

[@reecebailey3513]

You the man Wayne. Taking a plant phys course and it's a bit above my chemistry knowledge for some topics this helped immensely!

[@ADNZ5442]

Thank you. Only video that explained it well🙏🙏🙏

[@noalune]

thank you so much! i couldnt find any videos that explained this well, im glad i stumbled upon this one :)

[@wbreslyn]

You're very welcome!

[@jualyal2622]

Thanks, easy to understand.

[@raziyabadat7468]

Thanks!🙏the explanation was good, I have not covered this yet but it seems interesting!👌

[@wbreslyn]

Awesome, it should be easy for you when you get to the topic!

[@raziyabadat7468]

I hope so

[@udveetpatil8002]

Thank you, Sir, for the past and present, and hopefully the upcoming future!

[@wbreslyn]

Glad I can help with chemistry!

[@WaqasAhmad-fx5wh]

@@wbreslyn Sir in our chem book the definition of surface tension is The surface tension is the amount of energy required to stretch or increase the surface of a liquid by a unit area Sir I think this definition is wrong cox we says that the surface molecules are compressed and they are experiencing inward pull so the surface area should be decreased not increase .Sir what do u think it should be increased or decrease.

[@wbreslyn]

@@WaqasAhmad-fx5wh That may be that they are taking into account how SA is measured. There are a number of ways: en.wikipedia.org/wiki/Surface_tension#Methods_of_measurement

[@huzaifaabedeen7119]

Hi Dr.B!! How does soap reduce the surface tension??

[@_Chafia]

Thank you Dr B :) It's interesting & very useful to know about this 💧

[@_Chafia]

If we put a mixture of H20 & D2O in a plastic container which one of these two molecules will adher strongly to the surface ? Thank you Dr B :)

[@wbreslyn]

@@_Chafia That is an interesting question. Data on surface tension for D2O and H2O are given here. en.wikipedia.org/wiki/Heavy_water#Physical_properties The surface tension is similar for H2O and D2O. Interestingly there is bigger difference in viscosity. I'm not sure there would be any difference in how they adhered to the surface since the motion would likely keep them moving around. Great question!

[@sameerrai9727]

Your video is very interesting and helpful for me Thank you sir

[@wbreslyn]

Glad to hear that, thank you for commenting!

[@akchaudhari1413]

That Video is Help in my Exam

[@nanak3363]

Very well put . Thanks.

[@wbreslyn]

Thank you!

[@CricketBuzz_AD]

I love this concept a say a mysterious thanks to you

[@wbreslyn]

You are most welcome!

[@CricketBuzz_AD]

@@wbreslyn sir you are from where

[@wbreslyn]

@@CricketBuzz_AD right now I'm in the US, near Washington, DC.

[@emmanuelstephen2208]

Thank you so much sir

[@petarmajstor2370]

Finaly l understand! lack of bonds on the surface make bonds itself stronger and that's surface tension

[@foroghdehghani7773]

actually perfect

[@wbreslyn]

Thanks!

[@sleepyfella]

Good job bro you will grow fast

[@wbreslyn]

Thanks, I hope so!

[@user-zk3lc6ce8s]

Why does forming lesser number of bonds result in forming stronger bonds?

[@shivichauhan9199]

yes, had the exact same question.

[@SakunShawanthaLiyanage]

Its not about number of bonds. Its about what are involved in making that bond.

[@shivichauhan9199]

@@SakunShawanthaLiyanage thanks

[@WaqasAhmad-fx5wh]

Sir in our chem book the definition of surface tension is The surface tension is the amount of energy required to stretch or increase the surface of a liquid by a unit area Sir I think this definition is wrong cox we says that the surface molecules are compressed and they are experiencing inward pull so the surface area should be decreased not increase .Sir what do u think it should be increased or decrease.

[@hahahaha-bm9xs]

when you put a needle very lightly on the surface of water, those water molecules under the needle got pushed down. The surface area is then increased as it is stretched.

[@souravbhoi418]

Yes sir, it's the concept of the chapter.But first term is Equilibrium. But sir you adjust my request .so, many many thanks....... I'm from India 🇮🇳🇮🇳🇮🇳🇮🇳🇮🇳🇮🇳🇮🇳

[@wbreslyn]

Interesting, perhaps they are talking about the contact angle in terms of equilibrium (en.wikipedia.org/wiki/Surface_tension#Contact_angles). They may jut be adding the term "equilibrium" as a qualifier. I'm not sure what surface tension that wasn't at equilibrium would look like.

[@souravbhoi418]

@@wbreslyn ya but thanx

[@MadScientist267]

I was looking to see if hydrophobic surfaces might be suitable as "permanent" seeding points for crystal growth... you didn't address it directly in this video but you did mention water skeeters... lol I played with a nest of these things incessantly as a kid... and it then occurred to me, the skeeter's feet never actually touch the water... I'm thinking this translates to a "no" for my original question, but maybe not, if the object is submerged, maybe enough pressure to cause points to stick through... Thoughts?

[@wbreslyn]

Yeah, I could watch skeeters for hours. They actually have small hairs on their feet that repel the water. It does seem you are right about hydrophobic surfaces not being suitable. I suppose shape would come into play. Like if you had a very pointed hydrophobic surface that might change things.

[@sayyarmuhammad5644]

Amazing

[@sayyarmuhammad5644]

Make vedios on daily rutein

[@wbreslyn]

Thanks!

[@zackaccount]

Thank you. As a layman who has only a vague recollection of high school chemistry, this really satisfied my late night curiosity.

[@kartvyasheth2087]

How did you run the simulation Did you program it yourself?

[@wbreslyn]

I used a program to do it. It's nice because it is an actual simulation based on data about the water molecule.

[@kartvyasheth2087]

@@wbreslyn is that available on mobile

[@wbreslyn]

@@kartvyasheth2087 Not that I know of, unfortunately.

[@kartvyasheth2087]

@@wbreslyn ok, thanks for replying 🙂👍🏽

[@wbreslyn]

@@kartvyasheth2087 No problem. Hey, you might like this, I believe it works on mobil: phet.colorado.edu/ I use their stuff quite a bit in my teaching and videos.

[@huzaifaabedeen7119]

But how does the surface tension of water let it resist external force?

[@Khaledf]

"Because they can't form many bonds those (?) bonds are going be stronger" Those on the surface you meant ? I did not get this point

[@satishgp1918]

I couldnt understand it too and there is no video that properly explains surface tension they just repeat what's written on wikipedia

[@satishgp1918]

If you found a better video please mind sharing it here

[@Khaledf]

@@satishgp1918 I have searched lot, yet I haven't found any thing that good.

[@user-jz4jz6us5p]

Isn't the water surface supposed to be concave inside a container cuz the cohesion is downward

[@wbreslyn]

It will be in a tube like a graduated cylinder. But think about a raindrop in a leaf. It isn't concave.

[@hanscarlosirch8044]

If I could give these videos two likes, I'd do.

[@suganthr7584]

Hi

[@wbreslyn]

Hello.

[@suganthr7584]

@@wbreslyn how are u

[@wbreslyn]

@@suganthr7584 Fine, thank you!

[@scarlettecreaser9148]

hello fellow classmates

[@shivichauhan9199]

"The water molecules on the surface don't form as many bonds as those in the middle of the water. Because of that, they are stronger." You didn't explain why having fewer bonds contributes to an increase in their strength?? Useless video.