The Sci Guys: Science at Home - SE3 - EP4: Water Glass Surface Tension - Surface Tension of Water

Welcome to episode four, season three of science at home. In this episode we add pennies into a full glass of water to show how surface tension will create a convex dome of water that rises above the rim of the glass. Surface tension is generated by cohesion and keeps an elastic tension between all the molecules in a liquid. The water has one of the highest surface tension. At the end of the episode you will be able to explain surface tension and you will be able to demonstrate the dome created by the surface tension of water.

Equipment and Ingredients:
Water
Glass
Food Colouring
20-30 Pennies
Measuring Cups
Gloves
Goggles
Lab coat or Apron

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[Alex-nucb]

Simple concept, yet the book makes it ridiculously complicated.
Thanks

[freaydkisaragi]

I came here because of jojo. All I can say is that Its your turn Mr. Joestar.

[ovahlord]

more importantly does the chocolate trick that d'arby did work?

[kashigi]

Lol I'm here from school but I love that there are Jojo fans here, I swear everything is a jojo reference.

[Johnnzee]

Please come back and make more videos! More kids are learning online more than ever, and your videos have been a god send for them.

[dhananjaybomidi]

thank a lot guys. searched the whole you tube, went baffled and then i meet your video..
Hats off!! nice creativity and concept explaining through your animation quality.

[pinkishinde]

If we had people like you in college it would be so fun

[dmandyzhou]

I love your videos! They are all easy to understand and are nicely explained. :)

[evanroberts]

Thanks for a concise and accurate explanation. This was excellent!

[SabyasachiChatterjee]

Rightly explained !
Super like.
Love from India

[iTpal]

Gravity doesn't push from the top. Atmospheric pressure does though. Gravitational field affects matter which is what generates the force of attractive kinetic energy - in this case this kinetic energy points down and is affected by resisting hydrostatic pressure and surface tension close to the age, whilst possibly being amplified towards the bottom centre.

[fretlessman]

I've been trying to answer this question for years. If you put water in a glass but don't fill it all the way up to the top, is there a difference between the surface tension in the center versus the edge?

[sarahkhaled]

u are the best one express that phenomenon thx

[MiketheHighLord]

I had a glass of salt water sitting on the counter. After a few day's, salt crystals formed up the side of the glass. I think you guys could make a great video explaining what happened there!

[josetteblocker]

Hi this is Autumn Falwell completing my QuestFest task. It took 31 pennies before the water spilled over.

[keelhnf]

Truly helps visualisation of surface tension. Thanks :)

[richardboatwright]

Not a word about the hyfrogen bonding which helps the water molecules stick together much stronger than some other liquids? Hydrogen bonding adds a lot to the surface tension.

Also you can do this experiment by dropping water droplets onto a penny. I could only get 11 drops back when we did this experiment in grade school.

[abhinavjain]

I have a question
why do liquids try to attain minimum surface area?

[Beyond_Belief]

Are there any practical examples for a body of water naturally conforming to the exterior of a shape?

[Ravi-nqqy]

Food for thought

From this experiment we can learn that we should always drink water from spherical shape pot.
Because surface tension very low.
When you drink water from any spherical shape storage object, water surface will be less tense and your intestine will remain open for good digestion.
Benefit of low tension water is not visible right away but in long run it does help your health.

Calculation
lets take cylinder shape glass of water,
and round shape water glass (we can ignore slight flat bottom of spherical glass)
area of object in cm2
spherical shape glass radius is 5 cm so area will be π * r * r = 78.54 cm2
area of cylinder shape glass with radius 2 cm and height 5 cm ( 2*π*r*h+2*π*r*2) = 87.96cm2

lets spherical volume in cm3 for each object
spherical shape object volume (4/3πr3) = 523.6 cm3
cylinder shape object volume (πr2h) = 62.83 cm3
which is very less then spherical object.

So there are way more water molecules are in touch with surface in regular glass of water then
water stored in spherical shape glass.