How do seasons happen?
Seasons come to us regularly. We have probably noticed that it gets warmer in summer or dry season while it get colder in the winter or wet season. However do we know how these seasons change?

Seasons happen and change every year. This happens because the earth tilts back and forth as it goes around the sun. During the summer, the earth tilts toward the sun. It makes half of the earth hotter. this condition is what we call summer. During the other half of the year, the earth tilts away from the sun. As a result, it makes that half of the earth cooler. This cool condition is then what we call winter.

The different parts of the world have the same season at different times. In the northern half of the world , winter happens during the months of December, January and February. The regions are such North America and Europe. In the other hand, the southern half of the world have winter during the months of June, July and August.The regions are like South America and Australia. How does this difference happen? The same season happens at different times because the top and bottom halves of the earth tilt away from the sun at different times.

What is a tornado?
Tornadoes are known as one of the most damaging disasters. What is the description of tornadoes? A tornado is a very powerful column of winds which spirals around a center of low atmospheric pressure. A tornado will look like a large black funnel which hangs down from a storm cloud.

The name "tornado" derives from the Latin "tonare". It means "to thunder." While the Spanish developed the word into "tornear" which means "to turn or twist". This is why a tornado is sometimes called twister or cyclone.

The winds inside a twister can spin around at speeds up to 500 miles an hour, but it usually travels at roughly 300 miles an hour. This speed twisting makes a tornado the most dangerous storm.

The average tornado has a diameter of about 200 to 300 yards. The smaller tornadoes are known as satellite tornadoes. These small offspring, about 50 yards across, can be very fierce and do lots of damage.

The forming of a tornado can be very quick. Sometimes it can form in a minute or less. A tornado can travel across the ground at high speeds, then it can suddenly vanish. Most tornadoes last less than twenty minutes and travel less than 15 miles. However, the super storms sometimes travel over 100 miles before they are exhausted.

Composed from: library.thinkquest.org/C003603/english/tornadoes/whatisatornado.shtml

Types of Volcanic Eruptions
Volcanic eruptions have caused some of the worst disasters in the world. They can wipe out entire cities and kill thousands of people.
The name of volcano comes from Roman term. It derives from VULCAN which is the name of Roman fire god. Romans believed that Vulcan lived on a volcanic Italian coast. Romans called the island VULCANO.

According to scientists, volcanic eruptions are divided in to four basic groups. They are commonly known as Hawaiian, Strombolian, Vulcanian and Peleean. The term of Hawaiian eruptions are named after the volcanoes in Hawaii. These volcanic eruptions are the least violent type. They produce highly fluid lava which flows quietly. This gradually builds up a shield volcano.

Strombolian eruptions are named after Stromboli. These result from the constant release of gas from the magma. As the gas escapes, it produces tephra that piles up, turning into a cinder cone. Strombolian eruptions happen when sticky magma plugs the central vent. This makes the magmatic gas build up pressure until it blasts. The magma is turned into volcanic dust and bombs.

Vulcanian eruption which comes from the ancient Roman belief, are more violent than the strombolian eruption. Vulcanian eruption happens and brings magma which is more viscous. Vulcanian explosions are usually larger and noisier than the Strombolian eruptions.

Paleean eruptions are famous as the most violent kind of volcanic eruptions. The name of paleean comes from the eruption of Mount Pelee, Martinique in 1902. It killed almost 38 thousands people. A Peleean eruption occurs when the magmatic gas build up tremendous pressure. This causes violent explosions with glowing clouds of hot ash and dust.

Simplified from: library.thinkquest.org/03oct/01027/volcaniceruptions.html

The Story of Sangkuriang and Tangkuban Perahu Mountain
Once, there was a kingdom in Priangan Land. Lived a happy family. They were a father in form of dog,his name is Tumang, a mother which was called is Dayang Sumbi, and a child which was called Sangkuriang.
One day, Dayang Sumbi asked her son to go hunting with his lovely dog, Tumang. After hunting all day, Sangkuriang began desperate and worried because he hunted no deer. Then he thought to shot his own dog. Then he took the dog liver and carried home.
Soon Dayang Sumbi found out that it was not deer lever but Tumang's, his own dog. So, She was very angry and hit Sangkuriang's head. In that incident, Sangkuriang got wounded and scar then cast away from their home.
Years go bye, Sangkuriang had travel many places and finally arrived at a village. He met a beautiful woman and felt in love with her. When they were discussing their wedding plans, The woman looked at the wound in Sangkuriang's head. It matched to her son's wound who had left severall years earlier. Soon she realized that she felt in love with her own son.
She couldn't marry him but how to say it. Then, she found the way. She needed a lake and a boat for celebrating their wedding day. Sangkuriang had to make them in one night. He built a lake. With a dawn just moment away and the boat was almost complete. Dayang Sumbi had to stop it. Then, she lit up the eastern horizon with flashes of light. It made the cock crowed for a new day.
Sangkuriang failed to marry her. She was very angry and kicked the boat. It felt over and became the mountain of Tangkuban Perahu Bandung.

How Earthquakes Happen
Earthquake is one of the most destroying natural disasters. Unluckily it often happens in several regions. Recently a horrible earthquake has shaken West Sumatra. It has brought great damages. Why did it occur? Do you know how an earthquake happens?

Earthquakes are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves. It make the ground shake. When two blocks of rock or two plates are rubbing against each other, they stick a little. They don't just slide smoothly. The rocks are still pushing against each other, but not moving. After a while, the rocks break because of all the pressure that's built up. When the rocks break, the earthquake occurs.

During the earthquake and afterward, the plates or blocks of rock start moving, and they continue to move until they get stuck again. The spot underground where the rock breaks is called the focus of the earthquake. The place right above the focus is called the epicenter of the earthquake.