Let me define surface tension to you first of all. It is a property which of liquid which makes the surface of a liquid to feel like an elastic membrane which is stretched out. This is a phenomenon which you will be able to observe in liquid drops which are small or even the bubbles of soap of any type of shape which is almost spherical. Some people also call it water tension. Because of this property exerted by a liquid, some of the insects are able to use to surface of water to stand. If you want to see how surface tension works then you can try to put a razor blade on the top of water in horizontal direction and you will be able to see the razor blade floating on the surface of water. Well, let me tell you that the razor blade is actually not at all floating, if you try to push the razor blade in to the water with even a little bit of force then you will see it will sink. I hope the surface tension definition is clear to you now.
Surface tension is a phenomenon which mainly depends on the attraction forces between liquid particles that are present in the liquid and the solid, liquid or gas whichever is in contact with the liquid. The molecules that are present in a water droplet does attract themselves but with only a little bit of force. The molecules that are present inside of the water droplet can be seen as it is being attracted in all of the directions with equal force by the molecules that surround it and this is what causes surface tension in water to occur. Energy that is responsible for this kind of phenomenon to occur of the surface tension can be easily compared to the energy or work that is required if you want to remove the layer of the molecules from the surface and it is in unit area.
The unit of the surface tension can be expressed in joules per unit area and it is the unit for energy. The value of water surface tension here is 0.07275 joule per sq. meter at a temperature of 20 degree Celsius. If we compare the organic liquids for example alcohols and the benzene, they do have less surface tension. If we look at the case of mercury, it has much more surface tension. If we increase the temperature, the overall force if the attraction in between the molecules will lower down which will result in the decrease of the surface tension.
Surface tension examples –
1. Floating a Needle
If you will try to place a needle on the surface of water very carefully then you will notice that it will not sink inside the water. The needle will not sink until the surface tension does not break.
2. Washing the Clothes with Cold Water
The main reason because of which hot water is used for the washing of clothes is that the surface tension will be lower and it is a far better wetting agent. However if the detergent there will lower the surface tension, the heating might be unnecessary.
3. Walk on the Water
Some of the insects are able to use to surface of water to stand as I told you earlier.
4. Razor Blade Floating on Water
You can try to put a razor blade on the top of water in horizontal direction and you will be able to see the razor blade floating on the surface of water. Well, let me tell you that the razor blade is actually not at all floating, if you try to push the razor blade in to the water with even a little bit of force then you will see it will sink.
5. Water Strider
It is an insect which is known for floating on water. You would see one in most of the lakes and ponds as the water is still there.
So this was the complete article on surface tension of water.
I hope this article was helpful to you. If you have any questions or any suggestions then you are welcome to mention them in the comments down below. Also let us know if you know any other example of surface tension and you want to share it with us then you can mention that in the comments below too.