WHAT IS ACID RAIN...?

Do you guys know what is acid rain....?

Acid rain is rain that has a larger amount of acid in it than what is normal. Acid rain is caused by smoke and gases that are given off by factories, and vehicles that run on fossil fuels. When these fuels are burned to produce energy, the sulphur that is present in the fuel combines with oxygen and becomes sulphur dioxide. Some of the nitrogen in the air becomes nitrogen oxide. These pollutants go into the atmosphere, and become acid. Sulphur dioxide and nitrogen oxide are also produced when coal is burnt for fuel. Acid rain destroys trees, harms wildlife and eats away the stonework in buildings. It also gives us asthma  and coughs!

IS THE EARTH A PERFECT SPHERE...?

A person who thinks about the shape of Earth may have a doubt that is the Earth a perfect sphere or not...?

If you look around, the Earth looks flat. Even before the middle ages, people did think it was flat. The flat Earth concept persisted till about 300 years ago. In fact, people used to think that if they sailed too far in one direction, they would fall off the edge of the Earth! Pythagoras was the first person to talk about the Earth being spherical. A practical demonstration on Earth's sphericity was achieved by Ferdinand Magellan's  expedition's circumnavigation. It was Sir Isaac Newton, who first claimed that the Earth is not spherical, but 'oval'. Today, we know that the Earth is not a perfect sphere. It is slightly flattened at the poles, and bulges at the Equator.

WHAT IS A BLACK HOLE...?

Hi guys do you know what is a black  hole....?

Black holes are the most mysterious bodies in the whole universe. Astronomers consider a black hole as a stage in the evolution of the star. They are probably formed when a supernova occurs. If a star is ten times more massive than the sun, no known force can stop the increasing gravity, and it will collapse to a point of infinite density. Before  this stage is reached, within a certain radius, light itself becomes trapped, and the object becomes invisible, and becomes a black hole. With the invention of invisible radiations like radio waves,ultraviolet, X-rays etc. locating the  invisible black hole has been possible. Black holes are the densest areas in the Universe.

WHY DON'T ARCTIC FISH FREEZE...?

We may think that why don't the Arctic fish fish freeze...?

Fish are cold blooded animals whose body temperature changes according to the surroundings. So, normally at the below freezing temperature of Arctic, fish should be freezing or they shouldn't be living there at all! The puzzle has been solved by scientists who have discovered that the fish do possess some antifreeze substance in their blood. The Arctic sculpin, manufactures an antifreeze protein in its blood. This depresses the freezing temperature of its plasma sufficiently. 

ARE THERE MOUNTAINS AND VOLCANOES UNDER THE SEA..? DO ALL SEAS HAVE TIDES...?

You may have a doubt that are there any mountains and volcanoes under the seas..?


There are thousands of mountains under the sea. All of them are volcanoes, but some of them do not erupt anymore. There is long chain of undersea mountains all the way down the Atlantic Ocean. It is called the Mid-Atlantic Ridge, and is the longest chain of mountains in the world. The highest sea mountains are over 10,000 metres tall.



You may also doubt that do all seas  have tides..?

Tides are caused due to the pull of the  moon, and to a smaller extent, the Sun. In  general, the larger body of water, the more noticeable the tide. The height of the tide depends on the size, shape, and depth of the sea in a given location. In enclosed seas like the Mediterranean, there is hardly any tide at all, because it is surrounded by land on all sides. The rise and fall of the water may be only a few centimetres.

WHO WERE THE FIRST ARTISTS...?

Have you guys ever think about the first artist....?

About 30,000 years ago, Man first began to paint on the walls and roofs of caves and on rocks. The most common themes in cave paintings are large wild animals, such as bison, horses and deer. Stone Age carvings have also been found as far north as Scandinavia. The main form o prehistoric art is 'rock art'. This includes petroglyphs, otherwise known as rock carvings. An example is the Blombos cave engravings. A second form are pictographs, which includes drawn or painted signs, geometric symbols, hand stencils, and hand prints, see for instance the tragic Gargas Cave Hand Stencils. Rock art can be seen in Europe, Asia, Africa, Australasia, Oceania and the Americas.

HOW DO EAGLES GLIDE, WITHOUT FLAPPING THEIR WINGS..?

When people see the Eagle flying , they may think that how do they do it without flapping their wings....?

If you watch an eagle's movement through binoculars, you will see that even though the bird appears to be gliding lazily, it is actually very active. Its outer wing feathers and tail  feathers are in constant motion, catching up-drafts of warm air, and steering the bird through the air currents. Like other objects, which are heavier that air, birds in flight are constantly falling. When a bird is in an up-draft of warm air, it is carried up more quickly than it falls.  At this time, it can fly higher. The bird now tries to keep itself in this column of air by steering with its wing and tail feathers. When the birds moves into a column of downward moving cooler air, it falls rapidly.  However , it now uses its wings to help it glide, as quickly as possible, into another column of upward moving warm air. The speed that the bird attained while gliding downward in the 'cool column' enables it to sweep upward more quickly when it enters the 'warm column'.