Explanation Text

SNOW

Snow, an amazing natural phenomenon: my love as warm Snow

Febdian Rusydi (Rijksuniversiteit Groningen)

At this time in Europe and the northern regions of the Earth the middle of winter. One of the interesting phenomenon of the moment winter is snow. Be unique because the ice crystals are soft and white as cotton it just comes naturally in the land of the four seasons or in places that are very high as Jayawijaya mountain peaks on Papuan. Why snow naturally could not present in tropical regions such as our country?

The process of the formation of snow

To answer that, we can start the process of occurrence of snow. Starting from water vapor that gather in Earth’s atmosphere, the water vapor cools to the point of condensation (i.e. the temperature at which the gas turns into liquid or solid forms), then rotate to form clouds. At the beginning of the formation of clouds, its mass is much smaller than the mass of the air so that the clouds float in the air just like wooden beams which floats on the surface of the water. However, after the steam collection continues to grow and merge into the cloud, its mass also increases, resulting in a when air was not able to hold him again. The clouds broke and the water particles ever fallen to Earth.

Water particles that fall it was pure water (not doped by other particles). Pure water does not freeze in temperatures of 0 degrees Celsius, because at the temperature of liquid phase changes to solid. To make pure water freezing temperature required is lower than 0 degrees Celsius. This also happens when we menjerang water, water evaporates when the temperature above 100 degrees Celsius because at 100 degrees Celsius is the change of phase from liquid to vapor. To speed up the change of the phase of a substance, usually added special substances, for example, salt is used to accelerate the phase of melting ice to water.

Usually the air temperature just below the clouds is below 0 degrees Celsius (air temperature depending on the height above sea level). But, the low temperature alone is not enough to create snow. When particles of such pure water in contact with air, then the pure water of distortion by other particles. There are certain particles that function accelerates the freezing phase, so that pure water is rapidly becoming the ice crystals.

Pollutant particles involved in this process is called nukleator, in addition to functioning as the freezing phase Accelerator, also the adhesive antaruap water. So the water particles (which are not pure anymore) joined together with other water particles to form larger crystals.

If the air temperature is not to melt the ice crystals, ice crystals falling to the ground. And here’s the snow! If not, the ice crystals melt and get to the soil in the form of rain water.

In many cases in the world, the process of the decline of the rain always starts with the snow some when she fell from the clouds, but then melted away when crossing the hot air. Sometimes, if the temperature is very low, the ice crystals can form small balls of ice and sleet. Bandung city included relatively frequently experience hail. So, this is why the snow was very hard down naturally in the tropical regions that have relatively high air temperatures than areas that are currently experiencing winter.

The unique structure of the snow

Snow Crystal has a unique structure, no snow crystals that have the same shape in this world (see figure URSnowflakesWilsonBentley.jpg) is like a fingerprint. Imagine, the snow‘s been coming down since the Earth was created up to now, and none of the snow has the same crystal structure!

The uniqueness of the snow is white in colour. If it’s snowing, the expanse of the Earth as white, clean, and seemed to be glowing. This is due to the Crystal structure of the snow allows snow to reflect all the colors to all directions in the same amount, then came the white color. The same phenomenon can also be seen when we see white sand, salt chunk, chunks of sugar, mist, cloud, and white paint.

In addition, the decline in snow provide warmth. This can be understood from the concept of the effective temperature. Effective temperature is the temperature felt by our skin, is influenced by three physical quantities: the measured temperature (by the thermometer), the speed of movement of the air, and the air humidity. Effective temperature is typically used to determine the comfort zone. On the beach, the measured temperature can be high, but due to the high winds we still feel comfortable. By the time the snow fell heavy, humidity rises and this influenced the effective temperature so on one condition we felt warm.