Why Does Thunder follow Lighting?

During the rainy season we often see lightning in the sky followed by thunder. Do you know what this lightning is and how thunder follows it? In ancient times whenever man saw lightning in the sky and heard thunder he used to believe that gods were angry and punishing him for some sin. Benjamin Franklin was the first person who, in 1872, scientifically explained the occurrence of lightning. In fact, whenever the sky gets overcast with clouds, the small particles of water present in them get charged due to air friction. 

In the process, some clouds become positively charged, while some others negatively charged. When a positively-charged cloud approaches a negatively charged one. There develops a potential difference of millions of volts between them. Because of this high voltage, there is a sudden electric discharge through the air between the two clouds and a streak of light is seen. This is called 'lightning'. The electric discharge through the air produces a large amount of heat due to which the atmospheric air suddenly expands. 

Lighting. 

With this sudden expansion, the innumerable molecules of the air collide with one another producing sound. This is called 'thunder'. Although lightning and thunder are produced simultaneously, yet we see the flash of lightning first. It is so because the velocity of light is very high i.e.,300000 kms.per second. On the other hand velocity of sound is only 332 metres per second. Thus, because of its high velocity, light immediately reaches our eyes, but the sound takes some time to reach our ears.

Whenever a charged cloud passes by some tall tree or high building, by induction, it produces the opposite charge on that tree or building. When the amount of charge so produced is very high, there is a sudden electric discharge in the air. It is then said that lightning has struck such tree or building.

To protect high buildings from such mishaps pointed rods of copper or some other metal are fixed on the top of buildings which passes through them and are buried deep in the earth.

These are called 'lightning conductors'. Whenever some charged cloud passes by such a building and produces opposite charge on it, the charge goes to the earth through the rod and does not damage the building. This is how buildings are protected from the lightning. 

THERE IS A CRACK IN EVERYTHING, THAT'S HOW THE LIGHT GETS IN.

- LEONARD COMEN.

Why is the Tower of Pisa Leaning?

Is the Tower of Pisa Leaning?

Everybody knows that in the city of Pisa in Italy, there is a beautiful tower that "leans" Very ew people know the reason of its leaning Every year thousands of people go there to see the der made of white marble The walls are four meters thick at its base. It has eight story and in 55 meters high. There is a stairway which leads to the top and has 300 steps From as top one can have a magnificent view of the city and the sea which is ten kilometer away.   

Leaning Tower of Pisa, Italy.

Now the question arises: What makes this tower lean and why it does not fall? At the top, the tower is five  meters away from the perpendicular. It leans over by five meters If we drop ball from it's top, a would hit the ground five meters away from its base. It was intended as a bell tower for the cathedral which is nearby. Its construction was started in 1174 and completed in 1350 When the construction started nobody thought that it would lean, but it started leaning after the third story was completed. The foundations of the tower were laid sand and this may explain why it leans. Since the tower started leaning, the plans of its constructs were modified and the tower was completed. During the last one hundred years the tower has leaned another 30 cm.

Now the question arises: Even while leaning, why does it not tall?  According to science anything well remain stable till the vertical line drawn from its center of gravity passes through The center of gravity is that point where the whole of the mass of the body is  supposed to be concentrated. Till today the vertical line from the center of gravity has been falling within the base of the tower. That is why it has not fallen. It is believed that when the tower leans further and the line from its center of gravity pass out of its base, it will fall down According to some engineers the tower will definitely fall one day.  

Rome Wasn't Built In A Day. 

Alexander the Great.

Even after many centuries of his death Alexander the Great is still regarded as one of the greatest conquerors of the world in human history. This brave soldier died in Babylon over 2000 years ago at the age of thirty-three only.

His empire, stretching from Greece to India, disintegrated after his death. But the cities founded by him are still there. It is said that he founded about 70 cities during his short span of life.

Alexander the Great.

The story goes that when Alexander was only a boy of fourteen, he tamed the wild horse Bucephalus whom nobody else had been able to control. He rode this horse in all his battles. This horse died in a battle in India. He built a town and named it after the brave horse.

Alexander's father, Philip, became the king of Macedonia in 359 B.C. He raised his own army and planned an invasion of the great Persian empire. But he was murdered in 336 B.C. in a palace conspiracy. After him, Alexander became the king at the age of twenty.

Macedonia Empire Under Alexander the great.

Alexander had received the training of warfare from his father. The great philosopher Aristotle was his intellectual mentor. After his father's death, a serious, revolt broke out in his kingdom. Alexander restored order in a very short time. The young Alexander attacked the Persian empire about 334 B.C. There he fought two battles and achieved resounding victories. He was well trained in the tactics of warfare. He was a fearless man. After conquering Persia, he attacked Egypt. He conquered Egypt also and established a city called Alexandria at the mouth of river Nile.

Alexander in India.

When Alexander entered Asia Minor, he was shown the chariot of the ancient king Gordius and was told of a legend that whoever could untie the knot binding the chariot would rule the world. Alexander seized a sword and cut the knot. By now Alexander was the king of Macedonia, Greece, Egypt, Persia and Asia-half of the known world. For six more years his army kept on marching and conquered Afghanistan, Hindu Kush, Samarkand, Tashkent and Khyber pass. Then he entered India. 

Porus surrendered to Alexander.

After entering Asia he started living in luxury. He married a rich and beautiful princess, Roxana. He fought his last great battle with the brave Indian king, Porus. He won this battle but with great difficulties. Alexander hoped to reach the river Ganga, but when his soldiers reached the river Beas, they refused to go further. They had been away from their homes for more then eight years. Alexander tried his best to persuade them but they did not move further. They marched back to their homes. Alexander developed high fever on the way and died in June 323 B.C.  

There Is Nothing Impossible To Him Who Will Try.  

The Egyptian Civilization

Ancient Egypt was an ancient civilization of eastern North Africa and it developed around the river Nile. Egypt was an agricultural state. The Egyptian turned desert patches into farmlands, irritating them with the Nile's water. The yearly flooding of the Nile enriched the soil and brought good harvests and wealth to the land. The people of ancient Egypt built mudbrick homes in villages and in country.

              Egyptian Civilization Map

The main Egyptian god was Amon Re, the king of all gods. One important Egyptian symbol was that of the solar disk surrounded by the sacred snake. Crocodiles were sacred in the ancient Egypt, and they were even embalmed. Ibis was the sacred bird.

                            Amon Re

Egyptians used hiéroglyphic inscriptions - a writing system using picture symbols or diagrams. These diagrams were thought to have magical powers.

             Hieroglyphic Inscriptions

 To preserve the magical power of their art. the Egyptians believed they must copy exactly the style handed down through the ages. This meant that most artists painted in the same way, and the people they painted all looked the same.

The Egyptians loved music and played instruments like the harp. They loved beauty and fashion; eye paint was worn both by men and women. They also used a lot of perfume and jewellery .

The Egyptian people believed that their rulers, or pharaohs, were gods, and that they would continue to work even after their death. So, they preserved the bodies of the kings through the process of mummification. Mummies were entombed and included food, gifts and provisions were kept there for the afterlife.

                 The Pyramid Of Giza 

The pyramids were built to contain the tombs of pharaohs To avoid the theft of the treasures and tomb's profanation, the architects built a real labyrinth of false passages inside the pyramid, to confuse the thieves. The pyramids were the earliest buildings ever to be made by precisely cutting and putting together great blocks of stone. One of the most famous pyramids is the Great Pyramid of Khufu. It has 2,300,000 blocks and each block in the pyramid weighs 2.5tons.

                      Mummification 

The civilization coalesced around 3150 BC and lasted for three millennia until the conquest of Alexander the Great...  

 “ From The Heights Of These Pyramids, Forty Centuries Look Down Upon Us. ”

                                   — Napoleon Bonaparte.