Water
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Snow

Article 3 Module 1

Fresh white snow

SNOW



Water appears white is when it is frozen trapping pockets and bubbles of air between the water molecules.



As we know, snowflakes are frozen water vapor.



Whereas snowflakes seen individually are colorless, a mass of snowflakes with entrapped air bubbles will appear white.



Here's what happens: when snowflakes fall and collect on the ground, they glue to other flakes through frozen bonds (hydrogen bonds) that bind water molecules together.



In doing this, they entrap pockets of air. 



The chaotic arrangement of air bubbles within snow will bounce (refract) light all over the place.



Enough light is reflected back to us from the surface of the snow as white light.



Blue color underneath the footprints

Blue color underneath the footprints

When snow is blue: 



After snowstorms, deep crevices in clean white snow can reflect blue light back to us.


The blue can be a startlingly bright sky-blue color.


The snow has to have a special character to achieve a blue color. 


The snow has to be more than 1 meter deep, starting out as wet snow, and with larger ice crystals.


This snow is heavy and very tightly bonded. The packing gets rid of any air pockets.


As light penetrates through the frozen water molecules, red light is absorbed.


The reflected light  from snow that is heavy and deep (and without air bubbles) will have a green/blue tint (cyan color).

CONCLUSION

A disorganized mass of air bubbles held in place by frozen water will reflect light. 



This is the whiteness you see in snow.

Picture Credits:


1. Hijab, J. White snow on the deck. Winter 2018.

2. Hijab, J. Fresh white snow in park. Winter, 2018.

3. By Yiyi Huli. Shutterstock, ID: 1465523039. In the cold winter, the outdoor road is covered with heavy snow. People walk on the snow to leave footprints. When there are more people walking, they become deep footprints. 

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