explanation text

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Tornado is the most damaging storm.The word tornado come from Spanish “Tronada” that mean thunder storm. Also come from Latin language ”Tonare” which mean rumbling. According to the story,the word tornado was taken from combination between ronada and Tornar in Spanish. Tornado is air column which rotate very fast and form relation between cumulonimbus cloud. Usually tornado has wind velocity between 177 km/hours or more with reach average 75 meters and attack several kilometers before disappearing. Several tornado which reach wind velocity more than 300-480 km/hours have wide more than one mile and can survive in the surface more than 100 km.
Tornado generally happens in the afternoon to evening. In America, tornado happens between 15.00-21.00. Although tornado has been research by the scientist, in every continent, most of tornado happens in America. In America, most of tornado happen in tornado alley in middle-west America. Other area which generally happen tornado are South Canada, South Africa, East and south Asia, Middle Europe, Italy, West Australia, New South Wales, and Indonesia. In Indonesia, usually happen in Sumatra and Java.

Tornado has some types. They are weak, strong and violence tornado. Weak tornado include 88% of all tornado. The wind velocity is less than 112 mph. Weak tornado happen about 1-10 minutes. Death because of this tornado are about 5% of the total death because of tornado. Strong tornado include 11% of all tornado. The wind velocity is between113-206 mph.This tornado happens in 20 minutes or more. The death because of strong tornado is about 30% of the total death because of tornado. Violent tornado is rarely happen. This include 1% of all tornado. The wind velocity is more than 205 mph or more. This tornado happens in one hours or more. Although rarely happen, this tornado can cause death about 70% of the total death because of tornado.

Before tornado happens, it has several signal. First, the sky seems dark. Then happen ice rain around the area, usually 20-25 minutes. After that, the situation will calm, but the sky become darker. Fourth, cloud moving around the area. Fifth, the sound of tornado heard. At the beginning, the sound like water fall, but in the process of time it will change until like jet plane which is very loud. A tornado usually move from southwest to north east.
The change of air layer is the cause of tornado. In this case, if the cold air layer is above the hot air layer, the hot air layer go up with velocity about 300 km/hour. The air which infiltrating from this side, cause wind rotate and form Tornado.

The process of tornado begin with storm followed by rain, thunder and lightning. When the temperature of the soil go up, the hot and moist air start to go up too. Then, when warm, the moist and cold air fill up the dry air. That upraised up, enter to the upper air layer. A thunderbolt cloud begin to form in this phase. The move of air go up is very fast. Wind from side cause the different direction and form a very very strong rotation.A cone, result of that air rotation start to form and seem from the cloud to soil surface so form Tornado.

How Rainbow is Formed

Rainbow is one of  optic phenomena that happens in the atmosphere of the earth naturally. We can see it at mountin range, or  when it is cloudy, or  when it is raining and rising of sun. We have to be the other side for looking.  We  just can see it a half of circle form, but acctually the rainbow is a circle form. We can see it perfectly, if it is seen by standing in the high place. It is real that rainbow is a circle form not like parabola form.

On the ground, we can not see perfectly, except if we are in the high place like in the air plane or standing on top of  moutain. When we are looking at rainbow’s colors, we will see them that ordered of red is on the highest order,  and purple is on  the lowest order.

Red is more dominant than another color caused by having biggest wave between others. Therefore the red one is in the highest order  and purple one is in lowest order. How rainbow is formed?  Try to watch it when light of sun concerns a 90-degree angle mirror or a glass prism side, or surface of  soap foam. We can see colors on the light. The light is rayyed to be some  wave lenght of light that it is seen by our eyes as red, bright red, yellow, green, blue and purple. These colors are compnents of light that they are called visible light. The other component is invisible light such as infrared (red is in the right side), and ultraviolet (bright red is in the left side).

So, we can see the beautiful rainbow because there are some processes to be beautiful rainbow that it appears in the sky.

Explanation Text About Snow

Water in its pure formis colorless. If there are impurities, the color of the water.Snowcan also take the color of other objects. For example, in the case of deep glacier ice blocks appear blue. But the snow is slightly different from the ice. Snow is a collection of small ice crystals and interconnected. Ice is clear and color less as the accumulation of crystals combine to form snowflakes.

Snow invisible to us because of the light.Snow fell from the top to the atmosphere and reaches Earth. Ice crystals allow the light that fall son them to get reflected on its surface. There are some crystal faces and the light because it's also so scattered. Has a wave length of visible light of different light show to us.When light strikes any object to be absorbed somewhere in the reflected light and the other part. Part of the reflected light reaches our eyes and make us recognize colors.

Light falling on the ice crystals do not pass through the glass for long distances, but they tend to change direction. Light reflected at an angle in the ice. As the snow there as a collection of some of the snow flakes on the ground, the light falling on them will not have a specific wavelength this reflected with some regularity. Thus, most of the light falling on the snow almost entirely be reflected back. The light that is reflected in the snow will stay white for most of the time as the total light and the reflected wavelength. Therefore, the snow is white.