How snowflakes grow? Why do they look so artistic?

 

Story of snowflake

Look at these snowflakes they look wonderful it’s so fascinating just to glare at them and think about their special shape and although they each look quite different from others still they are also very similar. What are those forces of nature that gave them their artistic shape and if there are the same forces involved then why do they all look so different? Today we together let’s try to solve mysteries behind these beautiful sculptures. Because the beauty of nature lies not merely in seeing it but the real beauty is revealed in actually understanding it. 

Let’s try to find answers to this mystery by asking questions. Because this is the first step of finding answers. The first question which cames in my mind or probably also in most of you. Why ice floats of water? At first, this question seems so dumb but if you look at any other solid and you put it inside its own liquid. It does not float only water does. To find this answer we have to look at the geometry of the water molecule. A molecule of water is made up of one oxygen atom and two hydrogen atoms. In the below image the larger circle is oxygen atom the smaller two are hydrogen atoms. This is how one water molecule should look. One thing to remember here is that it’s a very simplified version of it. In the second image, you can see a  much much more accurate picture   

Of water molecule. Here, we can see electrons are not just points but instead are much more like a cloud-like structure. When two hydrogen atoms came close to one oxygen atom they get attached with it due to electrical force of attraction. Because oxygen has more electrons than needed and hydrogen has fewer electrons than needed. Because of this imbalance in electronic arrangements, the atoms of these two elements stick together and forme a single molecule of water. But look at the second picture once again there is something wrong with it? It looks like a kind of bulgy. Because of the electrons of hydrogen pushing the electrons of oxygen outwards forms this bulge we see here. As a result, more electrons are at the bulge side and fewer where the hydrogen is. This makes one side of the water molecule negative; at oxygen side and another side positive; at hydrogen’s side. This is called an electric dipole i.e. something that has both the electric charges positive as well as negative.  Due to the formation of this dipole one molecule of water attracts other water molecules together. On lowering the temperature these molecules come much closer and together they form a hexagon like structure. You can get the idea from the picture below. As you can see from the picture because the hexagonal structure of an ice molecule takes more space than a single water molecule the density of ice is less than that of water.

  

   

And as we all know since the days of  Archimedes’s Eureka that less dense things always float on top of a high-density liquid. This is the reason why ice floats on water. Hey look at the image again can you see a shape a hexagonal structure that though little resembles the structure of snowflakes. But still, its quite different from a snowflake. Why? Because the story is still incomplete. When a new molecule of water comes near this hexagonal structure it sticks at the edge of it and because of same dipole attraction and gradually more and more new molecules continue to stick at the edges. As a result, the development of branching is seen. And gradually as more atoms stick to the branches a star-like structure starts to appear. Refer to the video below;

    

         

 

Now, we are very close to unravelling the mystery behind the shape of snowflakes. Let’s see the whole story from the eyes of a snowflake. A dust particle in the cloud attracts water molecules around it. When this cloud goes to some cold place and as water freezes, the water molecules start to form a hexagonal structure. Slowly, flakes will start to form via this hexagonal structure. As these hexagonal structures get heavy they start to fall inside the cloud and while falling they attract more molecules of water which then sticks on their edges. When this cloud goes to a little warmer place, some of the ice starts to melt a little bit.  suddenly when it gets hit by air a side branch starts to form. As more water molecules come closer to this branch, more and more spikes form on it. And as a result full a snowflake is formed. And that’s it. As to how much water molecule will come in the way while falling depends upon the path of fall. The shape of a snowflake depends on the path it takes to fall. Because the path a snowflake will take to fall is always going to be different as the probability that two snowflakes will take the same path is nearly zero. Therefore we can say; no two snowflakes are identical.  One more point to remember here is that in addition to the path of fall, the shape of a snowflake also depends upon time water takes to freeze and upon different weather conditions.

        

   

Now next time when you will see these snowflakes. You will not see its visual beauty but also it real beauty which is hidden in understanding it. thank you  


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