I decided to speak to you in this "instructable" of the surface tension also called water tension.
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What is the interest to know : the superficial tension?
- To know the cleanliness of the material.
- In order to know if it is bondable and / or Printable
- To know if has been treated
I advise you to go see the video.
For this first experiment, I use a test tube that I fill to the brim.
Do you think that one can put higher than the height of its walls ?
When water is poured above the boundary of a container,
the liquid assumes a spherical shape,
so that its walls occupy the least possible of surface.
It not overflow.
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Step 1: The Water Tension on a Coin
For this second experiment I use a coin.
The surface tension keeps water molecules tied together, forming a kind of membrane or skin.
This half sphere is called meniscus.
Its height is even higher than the height of the coin.
And when the tension is too strong the membrane is broken and iteh water overflows.
Step 2: The Water Tension With Pepper and With Milk
In this third experiment, a plate with water is sprinkled with pepper, the pepper floats thanks to the surface tension and if a drop of dishwashing liquid or soap is added, this breaks up part of the surface tension. And the pepper and push back on the edges of the plate.
In this fourth experiment, on plate with milk , drops dyes are add in the center. It is the same principle as pepper but much more artistic. When you add a drop of dishwashing liquid this is what happens.
Step 3: Water Drop on Ceiling
In this fifth experiment. When a drop of water is added to a sheet, it takes on a spherical shape.
Do you think a drop of water can fit on the ceiling? The answer is yes. This tension is so strong that it maintains the drop of water hanging on the turned-up sheet. It is therefore possible to have a drop of water on the ceiling.
Step 4: Tension of Water in a Glass
From the sixth to the thirteenth experience
Here I use a glass filled with water. Do you think we can float metal? The answer is yes. The trombone floats. This surface tension can be overcome by exerting a simple pressure on the object and it flows or as with pepper add a drop of dishwashing liquid that is surfactant and tension is broken. A cutter blade can be floated, Float a safety pin, Or needle, brief you will have understood a whole lot of object. With a material density greater than 1. Impressive not? This shows you the strength of this superficial tension.
Step 5: Make a Compass With Water Tension
Experience fourteen to sixteen
If you magnet the trombone,
It will indicate in addition to floating the magnetic north.
It's the same as for all metals even the cutter blade.
You learned at school how to make a compass with a cork and a needle Why use the cork,
why not tell us about the surface tension.
Really impressive no ?
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Step 6: Water Tension With a Bottle
If a water bottle is drilled with several very close holes, each hole evacuates the water by a separate jet.
If one passes a finger horizontally in front of these holes the superficial tension force gathers the jet in 1 alone.
By ironing the finger vertically the jets are again distinct.
The liquid gathers the jet in 1 alone to minimize its surface
Step 7: Caps Perforated, the Bottle Does Not Sink
I pierced the stopper of a bottle about 12.5 cm.
I fill the bottle and close the cap do you think the water will sink?
Thanks to the tension of the water and the pressure of the air, one notices that the water does not flow.
It is the same principle that when you drill a bottle of water with the stopper closed the water does not flow.
Step 8: Strength of the Water Tension With a Rectangle
If you take a rectangle made with wire and plunge it into soapy water
On the rectangle I pose a wire. While there are of two sides of the fil a soapy film the iron wire remains in balance if we broken a part, the attraction force of the remaining part rolls the cylinder to decrease the surface but With the inertia of the rotation the thread falls and the second part disappears
Step 9: Force De La Tension De L'eau Avec Un Cercle
Taking a ring made of iron wire, a cotton thread is attached to the untensioned medium. This ring is dipped in soapy water. From each side of the wire a film of soap appears.
If one of the soapy surfaces is punctured.
the wire stretches because the remaining part of the soap film pulls the thread towards it to minimize its surface area. If one breaks the second part the wire is no longer subjected to surface tension and it hangs again freely
Step 10: Strength of Water Tension With a Tetrahedron
Always with the iron wire I can create a regular tetrahedron,
which you think it will pass ?
There are not 4 sides but 6 sides. Impressive no ! The common point of its faces and a central point. Mathematically it can be shown that the total surface of its 6 sides is less than the total surface of 4 sides of the tetrahedron. The liquid to find the best geometric solution to reduce the surface.
Step 11: Strength of Water Tension With a Cube
And with a cube what do you think it will happen?
One would think that each of the 6 sides would have a soapy film. But again it is not the case there are not 6 sides but 9 sides.
Impressive no !
The common point of its 9 faces and a central face which is a square. Again mathematically it can be shown that the total surface of its 9 sides is smaller than the total surface of the 6 sides of the cube.
The liquid thus finds again the best geometric solution to reduce its surface.
I hope you enjoyed this instructable and this experiment.
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