Little Einsteins Flight

GENERAL KNOWLEDGE Pt. II

• WHAT IS THE SLENDERNESS RATIO?

Columns used for construction have a definite value called the crippling load or buckling loadthe load at which the column bends or buckles but does not break. The effective length of the column is the length of an equivalent column of the same material and cross sectional area with hinged ends and having the value of the crippling load equal to that of the given column. The least radius of gyration is the radius of gyration where the least moment of inertia is considered. The ratio of effective length to the least radius of gyration is called the slenderness ratio of the column.

• WHAT IS SPECIAL ABOUT TEMPLE SQUARE?

The Temple Square in Utah is very religious place for the members of The Church of Jesus Christ of Latter Day Saints. It's symbolic of the holy ordinances or covenants that take place there To Mormons, the Gospel of Jesus is not complete without temples The Temple Square is special because it reminds the Mormons of the sacrifices by the pioneers who erected it. It is also the headquarters of the Church of Jesus Christ of Latter Day Saints.

• WHO DISCOVERED SATURN'S RINGS?

Christian Huygens, a Dutch physicist and astronomer, found out that Saturn has rings. He also discovered the Titan, the moon of Saturn.

• IS THERE ANY MAGNET WITH A SINGLE POLE?

Magnets found in nature and those made by man, are found to have two poles without exception. In contrast, electrical charges can be separated from each other. Several experiments to detect magnetic monopoles have been inconclusive.

• WHEN DID THE FIRST MANNED BALLOON FLIGHT TAKE PLACE?

In the late eighteenth century two French    papermakers, the Mont golfer’s brothers, began experimenting with hot air balloons. On Oct 15, 1783, a French scientist, Francois de Rozier became the first person to make a balloon ascent. He rose to a height of 80 ft in a balloon made by the Mont golfers.

• WHAT IS VSAT THE ACRONYM FOR?

VSAT stands for Very Small Aperture Terminal. VSAT nodes are networked together, using an antenna directed at a geo-stationary satellite. VSAT technology is used for transmission of information and is extremely popular in banking and financial services, Multisided manufacturing and for linking government offices.

• HAVE YOU HEARD OFBUCKYBALLS?

Buck balls   are   microscopic spheres of 60 carbon atoms that resemble a dome. They have cavities large enough to hold other atoms — even full molecules. Unless heated to a very high temperature, the contents of the cavities do not emerge. This has enormous potential in the fields of medicine, miniature mechanics, battery technology and high strength materials.

• WHAT IS 'NUCLEAR WINTER'?

'Nuclear winter' is used to describe the aftermath of a nuclear explosion caused due to a nuclear war or a nuclear accident. The impact of this explosion would be so devastating that unquantifiable amounts of dust and smoke would be released into the earth's stratosphere. This would block the sun's energy from reaching the surface of the earth, thereby lowering the temperature. The period of this effect would be determined by the intensity of the explosion. 'Nuclear winter' would threaten the existence of life on Earth.

• HOW DOES A GAS LIGHTER WORK?

Certain crystalline materials (like quartz, |Rochelle salt and certain ceramics) have piezoelectric behaviour. When you apply pressure to them, you get a charge separation within the crystal and a voltage across the crystal that is sometimes extremely high. For example, in a barbecue lighter, the popping noise you hear is a little spring-loaded hammer hitting a crystal and generating thousands of volts across the faces of the crystal. A voltage this high is identical to the voltage that drives a spark plug in a gasoline engine. The crystal's voltage can generate a nice spark that lights the gas in the grill.

• HOW DOES A PILOT KNOW THE ROUTE TO A DESTINATION HE IS FLYING?

Pilots rely heavily on computerized controls and with the assistance of the autopilot and the flight management computer, steer the plane along their planned route. They are monitored by air traffic control 'stations they pass along the way. They regularly check their fuel supply, condition of their engines and the air-conditioning, hydraulic, and other systems. Pilots may request a change in altitude or route if circumstances dictate.

• WHAT KIND OF HEALING DID DR EDWARD BACH PIONEER?

Dr Edward Bach pioneered a kind of healing called flower remedy therapy. This treats predominantly mental and emotional manifestations of disease, relying on administration of remedies derived from the flowering parts of plants. Dr Bach considered total 38 remedies sufficient to treat the most common negative moods that afflict mankind. After his death, many remedies were added and now the total is more than 200. He believed that the remedies were divinely enriched.

• WHY DO WE FEEL THAT THE AIR IS FRESH AFTER IT RAINS?

PEOPLE living in cities like Mumbai, Delhi and Bangalore are bound to feel that the air is fresh after the first heavy monsoon showers. This is because the bowers bring down from the sky, gases like sulphur dioxide, carbon monoxide, etc. These first monsoon showers, however, cause harm to many freshly planted saplings in these cities.

• THE FILAMENT OF AN ELECTRIC BULB IS HEATED TO VERY HIGH TEMPERATURES. HOW COME IT DOES NOT BUM?

THE filament does not bum because the bulb is filled with inert gases like argon and nitrogen. Oxygen is necessary for any combustion.

• WHAT ARE ASTEROIDS?

• WHO INVENTED THE BICYCLE?

THE first known patent of a machine that resembled a bicycle was given to Jean Theson in 1645. It had four wheels and was driven by two men. The first two-wheeled machine was invented by a Frenchman, Baron Karl de Drais (Baron von Drais) in 1818. But it did not catch on. What caught on was the bicycle, invented by a blacksmith, Kirkpatrick Macmillan of Scotland.

• HOW DO FORESTS HELP TO PREVENT FLOODS?

ONE of the major reasons for floods is erosion of soil from the area near thd banks of

the river. Forests have a dense cluster of trees in them. The roots of the trees hold on to the soil and prevent the erosion. It is therefore important that trees should not be cut indiscriminately, particularly near the banks of the rivers.

• DO VOLCANIC EXPLOSIONS AND EARTHQUAKES OCCUR INSIDE OCEANS ALSO?

The waves that we see in the seas and oceans are mainly caused by air currents. The size of the sea waves depends on the speed of the wind and for how long the wind has been blowing. Tide and ebb are caused by the pull of the moon (and to some extent, the pull of the sun) on the water. Mighty waves like tsunamis are caused by earthquakes below the water surface in seas and oceans.

• WHAT IS VISCOSITY?

Viscosity is a property seen in fluids that offers resistance to a body moving through them. It is equivalent to friction. Whenever a body falls through a viscous fluid, it reaches a terminal velocity or uniform speed due to the viscous force that balances gravity.

• WHY IS IT THAT WE CAN WALK MORE EASILY ON WET SAND THAN ON DRY SAND?

Have you not come across the Newton's Laws Of Motion? Everyone continues in a state of rest or uniform motional, unless compelled to do otherwise by an impressed (external) force. Walking is possible because the ground on which we walk offers some resistance. Assuming the resistance is zero, the foot that is placed forward will keep moving forward and you will fall. Even dry sand offers some resistance. That is why you can walk on it, if you are careful. Wet sand offers much more resistance and hence you can walk more easily on wet sand.

• WHAT IS A RETRO-ROCKET?

Newton’s first law of motion governs a spaceship travelling in space: It continues to travel at uniform speed. Since there is no reaction in space, a retro-rocket fired in the direction opposite to that of the motion, reduces the speed of the spaceship.

• WHAT IS TORQUEWRENCH?

• AN OTOLARYNGOLOGIST IS A PHYSICIAN. WHAT DOES HE SPECIALISE IN?

An otolaryngology’s is a physician who specializes in the problems of the ear, nose and throat (ENT). Myocardial infarction is the technical term for...? Unique is the application of liquid nitrogen to destroy warts.

• WHAT IS THE WIND CHILL FACTOR?

Wind chill is the rate of loss of body heat due to the motion of air. In simple parlance, a strong wind can make it much colder than the ambient temperature. Paul Siple coined this term in 1939 during an Antarctic expedition.

• WHAT IS EUTROPHICATION?

The process by which water becomes more nourished either by the natural process of maturation or artificial processes.

• WHAT IS A DIAMOND MADE OF?

A 100 million tears ago, when the Earth was cooling carbon deposits were exposed to extreme heat and pressure by molten rocks. These deposits crystallized to form diamond mines. Incidentally, the diamond is the hardest material known to mankind. If so, then how is the diamond cut to various shapes for use in jewellery? Saws made from diamond dust cut the diamond. Over 80 per cent of diamonds are used in the industry itself.

• WHAT IS A RE-ENTRY VEHICLE?

Whenever a spaceship returns to earth, it encounters tremendous friction from the atmosphere that generates heat. In order to ensure the safety of astronauts and the expensive apparatus, the spaceship is shielded by using heat resistant material. Scientists from the former Soviet Union were the first to deploy the re-entry vehicle successfully in the early Sixties.

• WHAT IS OZONE?

Ozone is the allotropic form of oxygen. It is used-in water purification and in treating gangrene. Its presence in the upper atmosphere is crucial as it absorbs energetic ultra-violet radiation. Industrial and vehicular pollution has resulted in the depletion of this life- saving molecule and is a cause of worry for the environmental scientists.

• WHAT IS HYDROPONICS?

Hydroponics is often defined as the cultivation of plants in water. Since many aggregates or media support plant growth the definition has been broadened to read the cultivation of plants without soil Growers use hydroponics techniques due to lack of water supply or fertile farmland. Home gardeners have used it to grow fresh vegetables year round and to grow plants in smaller spaces. Greenhouses and nurseries grow their plants in a soilless, peat- or bark-based growing mix.

• WHAT IS SIDEREAL TIME?

A sidereal year is the length of time it takes the Sun to move from a position relative to a fixed star and back to the same position again, as observed from the same location on Earth. It is equivalent to 365 days, 6 hours, 9 minutes and 11 seconds.

• WHY THE BALLOON IS CALLED THE POOR MAN'S SATELLITE?

Unlike hot air balloons, which are used in sports, the hydrogen filled is used for scientific, metrological and military purposes. They can carry payloads of a few tons. They are extensively used for astronomical observations, especially to study X-Ray emissions from stars.

• WHAT IS CORIOLIS FORCE?

Whenever a body is moving in a circular path, it experiences centripetal force towards the center of the circle. If you walk within a bus that is taking a turn, an additional force acts upon you. It is called the Coriolis force, a force that emanates from two simultaneous motions of the same body.

• WHO IS THE FATHER OF GAS-FILLED LAMPS?

Irving Langmuir studied chemical reactions at high temperatures and low pressures. One of the spin-offs of this research was the development of gas-filled lamps.

• WHAT IS THE DIFFERENCE BETWEEN AN ATOMIC AND A NUCLEAR BOMB9

Nuclear bombs are of two types — those that depend on fission, like atomic bombs, and those that depend on fusion, like hydrogen bombs. The former get their explosive energy from the splitting of atoms in materials like uranium or plutonium, which takes place automatically. On the other hand, hydrogen bombs, which are also known as thermonuclear bombs, depend upon the fusing together of atoms, as is taking place in our sun, to release much vaster quantities of energy than atomic bombs. The fusing requires very high temperatures; hence atomic bombs are generally used as triggers for hydrogen bombs. Hence, every atomic bomb is a nuclear bomb, but every nuclear bomb is not an atomic bomb.

• WHAT IS THE DIFFERENCE BETWEEN CYCLONE, HURRICANE, TORNADO AND TWISTER?

Technically, a cyclone is any kind of circular wind storm. But now, it is only used to describe a strong tropical storm found off of the coast of India. Hurricanes and Typhoons are the same thing, but in different places. On the coast of Florida it is called hurricane. In the Philipines, it is called typhoon. Hurricanes occur in the Atlantic and typhoons, in the Pacific. Basically, hurricanes and typhoons form over water and are huge, while tornados form over land and are much smaller in —size. A tornado is a violent windstorm characterised by a twisting, funnel-shaped cloud. In the United States, twister is used as a a colloquial term for tornado.

• WHEN DOES RESONANCE OCCUR?

Resonance occurs when two or more objects naturally vibrate at the same frequency and the sound produced by one object, causes the other to vibrate. Strings or air columns tuned to vibrate at particular frequencies result in the generation of music. Resonance’s can be destructive too. Making individual parts resonate can damage Bridges. This happens when a strong wind blows or a mechanized army convoy passes over it.

• DO YOU KNOW WHAT HAPPENS WHEN ANTI PARTICLES CLASH?

Every elementary particle is known to have an anti particle with opposite properties. Whenever the two meet, they annihilate each other and give out energy twice the mass of the particle.

• WHO DISCOVERED PIEZO-ELECTRIC EFFECT?

Modern kitchens are equipped with piezo-lighters. Certain substances produce currents when they are subjected to pressure. Pierre Curie, husband of Marie and co-discoverer of radium, was the one who discovered piezoelectricity.

• WHAT IS INERTIA?

1. It is the property of a body to stay in a state of rest or uniform motion unless acted upon by an external agency. It is believed that the mass of a body is the total measure of its inertia. Scientists are conducting experiments    to    distinguish between inertial man and gravitational mass.

• WHO DEVISED THE PRECISE NATURE OF PLANETARY MOTION?

Johannes Kepler, the German astronomer, devised major laws of planetary motion. After 17 years of observation, Kepler found that orbits, of planets around the sun are ellipses and not circles.

• WHY ARE QUARKS IMPORTANT?

"Three quarks to muster mark," said James Joyce. Indeed, three quarks fuse together to form nucleons: Protons and neutrons that make the atomic nucleus. Quarks are believed to be the basic building blocks of matter.

• WHERE ARE TRANSURANIC ELEMENTS FOUND?

Transuranic elements are not found in nature but have been created artificially in the laboratory. They represent atomic numbers 93 to 109, listed after the last stable element, uranium.

• IN WHAT WAY IS THE NAME DE BROGLIE CONNECTED WITH WAVELENGTH?

1. In modern physics, wave-particle duality of the microscopic world continues to battle the scientists. Light is made of waves but it can also be described as consisting of tiny particles called photons. A sub-atomic particle   can be described as having wave properties. De Broglie, a French physicist, was the first to give a formula for the "wavelength" of the particle.

• WHY THE ROBOT IS NAMED SO?

The word originates in the Slavic "Robota7, meaning compulsory work. Robots are used in hazardous environments. Now robots have also been powered by artificial intelligence.

• WHAT IS PARAFILAX?

1. Parallax is the apparent displacement of an astronomical object due to the change in the field of the observers. The very fact that we observe stars from the surface of the earth instead of its center causes geocentric parallax while heliocentric   parallax   occurs because the observation is carried out from the earth and not from the sun. In modern photography, this term is used to describe the difference between the view of an object through the lens of the camera and one seen through a separate viewfinder.

• WHICH IS THE BIGGEST MISSILE TEST CENTRE IN THE WORLD?

Poker Flat Research Range (PFRR) is the world's largest, land-based rocket range. It has a chain of downrange flight monitoring, observing and recovery stations from inland Alaska to Spitzbergen in the Arctic Ocean. Poker Flat is a sounding rocket launch facility 30 miles northeast of Fairbanks used for auroral and middle to upper atmospheric research. The Geophysical Institute of the University of Alaska, Fairbanks, operates it.

• HOW DO FORESTS HELP TO PREVENT FLOODS?

ONE of the major reasons for floods is erosion of soil from the area near the banks of the river. F'orests have a dense cluster of trees in them. The roots of the trees hold on to the soil and prevent the erosion. It is therefore important that trees should not be cut indiscriminately, particularly near the banks of the rivers.

• WHY ARE NOBEL PRIZES GIVEN ONLY IN NORWAY AND NOT IN ANY OTHER COUNTRY?

THE Nobel prizes were founded by Alfred Nobel,    Norwegian chemist, engineer and industrialist.

• WHY IS SOME SPACE LEFT BETWEEN RAILS ON THE RAILWAY TRACK?

YOU must have learnt in school that heat expands and cold contracts. This means that as a result of heat, all bodies expand. (There are rare exfor this expansion, a little space is left between rails.

• HOW IS THE INSTRUMENT FOR MEASURING THE INTENSITY OF EARTHQUAKES CALIBRATED?

`The Richter scale is used to measure the magnitude of an earthquake. Magnitude is a measure of an earthquake's size, but rather than being a direct measure of the intensity of the ground shaking, it is a reflection of the strength of the seismic sound waves emitted by the earthquake, a phenomenon that can be detected at great distances from the earthquake's epicentre. Because an earthquake's magnitude can be determined solely

by routine measurements made by seismometers, magnitude has become an important measurement commonly recorded on seismograms. The scale is logarithmic — this means that a factor-of-10 difference in actual earthquake energy corresponds to a difference of one whole number on the scale.

• WHAT ARE SUNSPOTS?

The dark spots on the surface of the sun are called sunspots. These areas are locations for sudden changes in the magnetic environment or the 'magnetic storms'. They appear darker in contrast to the surrounding areas, hence, the name.

• WHY IS A TRACTOR'S EXHAUST PIPE BENT UPWARDS?

As the exhaust gases of an automobile are hot and tend to rise upwards, an upward bending pipe is the most natural shape, hi a tractor, the driver's seat is directly behind the engine and usually open. So, a backward-bending exhaust pipe will throw the exhaust gases directly at the driver. The rear part of a tractor is broader than its engine. Even a sideways-bent exhaust pipe will have the same effect. As a tractor has various agricultural attachments and a trailer, the exhaust pipe cannot be extended behind its rear tyres from below its chassis. A tractor works mainly on rough terrain which could damage an exhaust pipe protruding downward from the chassis.

• WHAT IS FUEL CELL TECHNOLOGY?

Fuel cell technology uses the fuel cell, an electrochemical energy conversion device. A fuel cell converts hydrogen and oxygen into water, and in the process it produces electricity With a fuel cell, chemicals constantly flow into the cell so it never goes dead — as long as there, is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals.

• WHAT IS THE CAUSE OF DELAY IN SATELLITE COMMUNICATIONS?

The communication satellites are normally geosynchronous. In other words, these satellites have the same period of revolution as that of the earth — 24 hours. To attain this, the satellite is launched at an altitude of 36,000 kms from the earth. The messages, sent by means of radio waves, travel this distance to and fro. Radio waves are transmitted at the speed of light, about 3 lakh kms per second. Therefore, approximately, one quarter of a second is lost in traversing the distance between the earth and the satellite.

• WHAT CONTRIBUTION DID LUIS ALVAREZ MAKE TO MODERN SCIENCE?

This American physicist developed the linear accelerator in 1946 for which he won the Nobel Prize in 1968. He and his son, Walter, first proposed that massive extinctions around the Jurassic — including that of dinosaurs, were caused by the impact of a large space object.

• WHAT IS SPELEOLOGY?

It is the science that explores and studies caves found under the earth's surface.

• WHAT IS WAVE-PARTICLE DUALITY?

In classical physics, all the physical phenomena concerning light, viz. reflection from a glazed surface, refraction through a prism, interference when two or more sources of light were put together and diffraction, the bending of light along edge of an object, could be explained with the wave theory. But this description does not hold for the microscopic world. In modern physics, light is made of discrete packets of energy.

• WHAT IS THE FARADAY CAGE?

The Faraday Cage, also known as Faraday Shield or Screen, is a network of parallel wires connected to a common conductor at one end to provide electrostatic shielding without affecting electromagnetic waves. The common conductor is usually grounded. It attenuates an electrostatic field, designed to prevent the passage of electromagnetic waves, either containing them in or excluding them from its interior space. It is named after physicist Michael Faraday, who built the first one in 1836.

• WHAT IS A PILOTLESS AIRCRAFT?

A pilotless aircraft, usually an MAV (micro air vehicle), is one which is programmed to go somewhere or do something on its own, or is a remote controlled aircraft piloted from the ground. Most pilotless aircraft are rather small in size. Pilotless aircraft used for dangerous jobs such as spying or exploring new places with a camera, which transmits the data back to the ground. They can be very useful as many are shot down or crash, and thus saving a real pilot's life.

• WHERE WAS INDIA'S FIRST ELECTRICITY-GENERATING STATION LOCATED?

The 4-5 megawatt hydroelectric power station near Sivasamudram falls of the Cauvery in Karnataka was the first major power station in India. Owned by a few British companies, it was set up by General Electric of the US. It was commissioned in 1902, and its output was mostly meant for the Kolar gold mines, located about 90 miles away much smaller power plants started functioning earlier in different parts of India. The first small hydro power plant, a 130-kilowatt plant, started functioning in 1897 at Darjeeling.

• WHY IS VENUS THE HOTTEST PLANET EVEN THOUGH MERCURY IS CLOSEST TO THE SUN?

The degree of hotness of a planet does not depend on as much on closeness to the Sun as on its atmosphere. Carbon dioxide has the tendency to absorb heat, which in turn increases the temperature. Mercury's atmosphere does not contain carbon dioxide (because of which all the heat is returned to space). Venus contains a high percentage of carbon dioxide due to which it is hottest planet.

• IS IT TRUE THAT THE SAHARA DESERT EXPANDS BY HALF A MILE SOUTH OF EVERY YEAR?

In the 1970s and 1980s, it was reported that the Sahara desert was expanding southward at a rate of 5 kms per year. But during the last decade USAs NOAA meteorological satellite observed that this 'desertification' was a myth. It is not so severe as earlier suspected. The deserts reflect much of the incoming solar radiations as compared to land with vegetation (during cloud-free days). Satellites measure this reflected radiations daily, from which the type of land cover or greenness can be inferred. Analysing such data for several years, it was observed that the Sahara was not expanding.

• IS IT TRUE THAT THE SAHARA DESERT EXTENDS BY HALF A MILE SOUTH EVERY YEAR?

It is true that the Sahara desert is expanding, but not just half a mile. It is extending at a rate of 30 miles south per year! Its stretch is engulfing degraded grasslands. Due to the extreme heat, the vegetation of the area is dying out, which results in more desertification. Thus, every year the area of the Sahara desert is increasing and scientists are working out methods to stop or decrease the rapid change. They say that if this continues, the whole of Africa will turn into a desert one day. Global warming is also a big threat in the expansion of the Sahara.

• WHICH IS THE SMALLEST SUB-ATOMIC PARTICLE?

The smallest particle is the quark, the basic building block of hadrons. There are two types of hadrons: baryons (three quarks) and mesons (one quark, one antiquark). Protons and the neutrons are stable baryons. There are also leptons, a family of elementary particles that includes electrons, muons, tauons, and neutrinos. Neutrinos were originally believed to have zero mass, but they have been found to have a very tiny mass, smaller than any subatomic particle. Calling someone a 'hadron head' is considered an insult among physicists.

• WHAT IS THE KUIPER BELT?

The Kuiper Belt is disk-shaped belt of billions of small, icy bodies orbiting the Sun beyond the orbit of Neptune, mostly at distances 30-50 times the Earth's distance from the Sun. Modern computer simulations show the Kuiper Belt to have been strongly influenced by Jupiter and Neptune.

• WHAT IS A 'NUCLEAR WINTER'?

The nuclear winter theory, proposed by scientists in 1983 and later on established by the US National Research Council in 1984, states that if only half of the collective nuclear weapons of Russia and US were to explode, they would release such enormous amount of dust, smoke and soot into the at- mosphere that sunlight would be completely blocked. This would continue till these clouds settled and consequently the earth's temperature would fall, creating a period of abnormal cold and darkness. A nuclear winter is also believed likely after a nuclear war. Essential life processes like photosynthesis would also be fatally affected, endangering plant and animal life.

• WHY IS A TRACTOR'S EXHAUST PIPE BENT UPWARDS?

As the exhaust gases of an automobile are hot and tend to rise upwards, an upward bending pipe is the most natural shape, hi a tractor, the driver's seat is directly behind the engine and usually open. So, a backward-bending exhaust pipe will throw the exhaust gases directly at the driver. The rear part of a tractor is broader than its engine. Even a sideways-bent exhaust pipe will have the same effect. As a tractor has various agricultural attachments and a trailer, the exhaust pipe cannot be extended behind its rear tyres from below its chassis. A tractor works mainly on rough terrain which could damage an exhaust pipe protruding downward from the chassis.

• WHAT IS FUEL CELL TECHNOLOGY?

Fuel cell technology uses the fuel cell, an electrochemical energy conversion device. A fuel cell converts hydrogen and oxygen into water, and in the process it produces electricity With a fuel cell, chemicals constantly flow into the cell so it never goes dead — as long as there, is a flow of chemicals into the cell, the electricity flows out of the cell. Most fuel cells in use today use hydrogen and oxygen as the chemicals.

• WHAT IS THE DIFFERENCE BETWEEN IRON AND STEEL?

The difference is percentage of carbon, the main alloy element. Those irons containing less than 2% carbon are known as steels while those containing more than 2% carbon are known as pig iron. Pig iron is obtained from iron pre by processing it with coke in a blast furnace. This pig iron is then further processed to reduce the carbon content in different furnaces to obtain steels. These steels can be then further processed to obtain alloy steels, stainless steels by adding elements such as silicon, manganese, chromium, nickel, etc.

• WHAT IS CRUSH DEPTH AND HOW IS IT MEASURED?

Crush or collapse depth is the submerged depth of the ocean at which a submarine will collapse due to the surrounding water pressure. A submarine's hull is normally constructed of steel or steel alloys to increase the diving depth of submarines. This is normally mathematically calculated; however, it is not always accurate.

• WHAT IS M-THEORY?

The String theory is currently the most promising candidate for a unified theory. It describes free particles as vibrations in strings in space and solves the problem of the

incompatibility of the two fundamental theories (GR & QTF). There are, however, five different string theories. The M-Theory is a theory of which all the five string theories are only different aspects. The M-Theory is an 11-dimensional theory that looks 10 dimensional at some points in its space of parameters. Such a theory could have as a fundamental object a membrane as opposed to a string.

• WHAT ARE MILANKOVITCH CYCLES?

The Pleistocene period in earth history, 1.8 million years to about 10,000 years ago, witnessed profound changes in the earth's climate characterised by repeated glacial and interglacial events. There were as many as 30 glacial intervals during this period. Milutin Milankovitch, a Serbian astronomer and mathematician, calculated in the early 1930s that the orbital parameters of the earth changed with frequencies of roughly 1,000,00 to 20,000 years. These were responsible for variations in the of solar radiations received on the surface thus causing glacial interglacial climatic changes. The exploration of the ocean floor since the 1960 has indeed identified the above periodicities and proved Milankovitch right.

• WHAT ARE MILANKOVITCH CYCLES?

Astronomer Milutin Milankovitch developed the mathematical formulae upon which these orbital variations are based. He hypothesised that when some parts of the cyclic variations are combined and occur at the same time, they are responsible for major changes to the earth's climate (even ice ages). A 1976 study, published in the journal 'Science' examined deep-sea sediment cores and found that Milankovich's theory corresponded to periods of climate change. Indeed, ice ages had occurred when the earth was going through different stages of orbital variation.

o        WHEN WAS THE FIRST SPACE SHUTTLE LAUNCHED?

The first space shuttle Columbia was launched into space on April 12, 1981 and landed on Edward Air Force base, California on April 14, 1981. Officially, it's called the Space Transportation System (STS) and it was the first reusable spacecraft. These shuttles carry payloads for scientific experiments, etc. 

• WHICH PLACE ON EARTH HAS NEVER RECEIVED ANY RAINFALL?

The Atacama Desert, spread between the Pacific Ocean and the Andes mountains in northern Chile has not experienced rain in its entire recorded history. Made up of salt

basins, sand and lava flows, it lacks vegetation or animal life. Its landscape is desolate

and moon-like and has been used to simulate the moon's surface in some experiments. The Quillagua meteorological station located in this desert has recorded an average annual rainfall of only 0.5 mm during 1964-2001.

• WHAT ARE CFCS? HOW ARE THEY RESPONSIBLE FOR DEPLETION OF THE OZONE LAYER?

THERE is a layer of ozone in the zone 10 kilometre to 50 kilometre above the surface of the earth. This layer of ozone protects life on earth from the harmful ultraviolet radiation in sunlight. CFC stands for chlorofluorocarbons used in refrigeration, air-conditioning, aerosols, etc. When these gases rise up in the atmosphere and reach the ozone layer they destroy it. Over the past ten years, in particular, the debate has been held again and again on this issue and steps have been taken to correct the situation. Many nations have agreed to discontinue the use and production of chloro-fluro carbons for the purpose of refrigeration or air-conditioning.

• I HAVE READ THAT SUN WILL BECOME A RED GIANT AFTER CONSUMING ITS SUPPLY OF HYDROGEN. WHAT WILL HAPPEN TO THE SUN AFTER THIS PHASE?

YES, according to astronomers, the sun is about 5 billion years-old; It is expected that the sun mil consume all the hydrogen in it and become a Red Giant. It will be so big then that it will engulf even the planets around it. Then there will be nuclear reactions, involving the vast Supply of Helium in it (formed from Hydrogen) and the heavier elements. As a result it will become a white dwarf, a star of small radius. It is estimated that the radius will be a hundred times smaller than the present radius. Slowly it will lose its luminosity and become a black dwarf. But stop worrying. It will take at least five billion years for this to happen.

• DIAMOND AND COAL ARE BOTH CARBON. THEN WHY DOES ONLY DIAMOND SHINE?

DIAMOND is carbon in its pure form and is made of the same element as coal. But there is a difference. Diamonds are formed at places at least 120 km below the surface of the earth under the enormous pressure of the rocks and the crust above them. It is true that diamonds have been found in levels higher than this, below the surface of the earth. But it is believed they too were originally formed deep below and shifted to higher points due to erosion of the soil or glacial action. There are diamonds of black colour too. They are not used as 'gems, but they are useful in making cutting tools in industry.

• WHAT IS THERE BETWEEN THE EARTH AND MARS?

SURROUNDING the earth is its atmosphere. Then there is space. Again as your spacecraft approaches Mars, it will have to pass through the atmosphere around Mars. Unlike the moon, Mars has an atmosphere.

• WHAT IS THE ALTERNATIVE TO PETROLEUM? FROM WHERE SHALL WE MEET OUR ENERGY REQUIREMENTS WHEN THE PETROLEUM RESOURCES ARE EXHAUSTED?

DESCRIBED above is one such resource: solar power. Automobiles which^run on batteries, charged by exposing them to sunlight, already exist. You must be aware that nuclear power reactors are also being established all over the world. Many scientists have expressed the possibility of using hydrogen as a fuel. We are yet to find a cheap way of separating hydrogen from water, which has two atoms of hydrogen and one of oxygen in its molecule. In Holland and Denmark, power is being produced from windmills. In countries like. Japan, power is being produced on a small scale from tidal waves. Let us hope that tomorrow's generation will learn how to meet its requirements of power.

• WHY IS THERE NO GRAVITATIONAL FORCE ON THE MOON?

THE moon has gravitational force too. The gravitational force exerted by a body depends on its mass. The gravitational force on the moon is about one sixth the gravitational force of the earth.

• WHAT IS THE MACH NUMBER?

The Mach number, in aerodynamics and fluid mechanics, is the ratio of the speed of an object through a fluid (gas or liquid) to the speed of sound in the fluid. The Mach number was named after the Austrian physicist and philosopher Ernst Mach. An airplane travelling at less than Mach 1 is travelling at subsonic speeds; at about Mach 1, transonic, or approximately the speed of sound; and greater than Mach 1, at supersonic speeds.

• WHAT IS A MACH NUMBER?

• WHAT IS THE CHANDRASHEKAR LIMIT?

The maximum limit of 1.44 times the solar mass (or sun's mass) of a star, to end its life as a white dwarf star, is known as the Chandrashekar Limit. This is the basic principle to determine the future of a star after the red giant phase. The stars with a mass more than 1.44 times the solar mass go through supernova explosions and end their lives as neutron stars or black holes. This limit was discovered by Indian astrophysicist S

Chandrashekar and hence it has been named after him.

o        WHAT IS PLANETARY ALBEDO?

Planetary albedo is the fraction of the incoming light reflected from a surface. A bright surface, such as ice or snow, has a very high albedo (close to 1, which would represent total reflection), whereas a dark surface, such as coal or soot, has a very low. albedo (close to 0, which would represent complete absorption). In the solar system, the Moon, which has a bare, rocky surface, has an average albedo of 0.12 (reflects 12 per cent of the light hitting it). The Earth, which is partly cloud-covered, has an average albedo of 0.37, while the albedo of Venus, which is completely cloud-covered, is O.65.

• WHAT IS THE CHANDRASEKHAR LIMIT?

In the 1930s, Subramanya Chandrasekhar, now recognised as the founder of relativistic astrophysics, address the important question: What happens to a star once it has burnt all its nuclear fuel? Chadrasekhar's answer was that it depends on the mass of the burnt core left behind. If the mass of this core (mind you, not the mass of the shining star) is less than 1.4 times the mass of the sun, the core will retire as a white dwarf star. Immediately above this limit, say up to three times the solar mass, the core will become a neutron star. If the mass of the core is still higher, a black hole will be formed. In an ordinary shining star, the force of gravitation is balanced by nuclear reactions. In white dwarf and neutron stars, by complex quantum forces. In a black hole, gravitation dominates. For this pioneering work Chandrasekhar belatedly received the Nobel Prize for Physics in 1983.

• HOW MANY PERSONS HAVE SET FOOT ON THE MOON?

Only twelve people have walked oh the Moon, each on one mission only. Nobody has walked on the lunar surface since 1972. The lucky astronauts are: Neil Armstrong, Edwin Aldrin, Charles Conrad, Alan Bean, Alan Shepard, Edgar Mitchell, David Scott, James Irwin, John Young, Charles Duke, Eugene Cernan and Harrison Schmitt.

• IS A RAY OF LIGHT VISIBLE IN VACUUM?

No, rays of light cannot be seen in vacuum. When a ray of light enters an enclosed dark room through an opening, light is scattered by dust particles suspended in the air and thus we see the path of the ray Actually we see the dust particles falling substance which can scatter the light. This explains the darkness in space though there are many light sources. We can see only the light sources and the objects, which fall in the path of rays.

• ON WHAT PRINCIPLE DOES AN ALTIMETER WORK?

There are basically two types of altimeters— pressure altimeters and radio altimeters. Pressure altimeters are aneroid barometers calibrated to indicate altitude instead of pressure. It is based on the principle of drop of atmospheric pressure with gain of height. The corrugated capsules inside the casing expand with gain of height. This expansion is magnified with the help of gears and levers to move the indicator over the dial. The mean sea level pressure is 1013.2 millibars or 29.92 inches of mercury which is taken as zero altitude and there is drop of 1 millibar for every 32 feet (approximately) gain of height. The instrument is calibrated accordingly to indicate loss/ gain of pressure in terms of height gained or lost. Depending on the pressure setting or datum, the instrument reads altitude (above MSL) or absolute altitude height (above ground level — AGL). A radio altimeter is a radar aid, which is effective only from 20 ft to 2,500 ft. It is basically used as a ground proximity warning system in mountainous terrain.

o        WHAT ARE PSEUDOHALOGENS?

Pseudohalogens are groups formed by combination of two or more P block elements (in the periodic table) with a unit negative charge e.g. CN- (CN Minus) cyanide group a combination of carbon and nitrogen with nonnegative charge. They are called pseudohalogens as they form covalent compounds, complexes similar to the halogens, the 17th group elements in the periodic table. They differ from halogens as they are able to polymerise unlike halogens and their complexes are not paramagnetic.

• HOW DOES THE INTERNATIONAL SPACE STATION MANAGE ITS WATER AND OXYGEN NEEDS?

The ISS's Environmental Control and Life Support System (ECLSS) helps in water and oxygen management for the astronauts. The ECLSS Water Recycling System (WRS) reclaims waste water from the shuttle's fuel cells, from urine, from oral hygiene and hand washing, and by condensing humidity from the air. Without such careful recycling, 40,000 pounds per year of water from the Earth would be required to resupply a minimum of four crewmembers for the life of the station. The primary source of oxygen is water electrolysis, followed by oxygen in a pressurised storage tank. Hydrogen left over from splitting water is vented into space. In ECLSS hardware racks, there is a machine that combines the hydrogen with excess carbon dioxide from the air in a chemical reaction that produces water and methane.

• HOW IS ZERO GRAVITY CREATED ON EARTH?

Zero gravity conditions result in weightlessness and the body begins to float in an enclosed space. A more precise term is microgravity or reduced gravity NASA's C-9B aircraft and Zero Gravity Corporation's modified Boeing 727 create these conditions by flying in long, parabolic arcs. By changing the flight path, they are able to create different values of g-force and therefore varying degrees of apparent gravity. More individuals are experiencing these conditions in preparation for space tourism or for adventure.

• WHAT IS THE NAME OF THE TENTH PLANET?

The tenth planet in the outer solar system was discovered recently. Right now, it's about 97 times further from the sun than the Earth and it's the farthest-known object in the solar system. Mike Brown (California Institute of Technology) along with colleagues Chad Trujillo (Gemini Observatory, Hawaii) and David Rabinowitz (Yale University) discovered it. It goes under the temporary name of 2003UB313; a new name has been proposed to the International Astronomical Union.

• WHAT EFFECT DO OCEAN CURRENTS HAVE ON THE EARTH'S WEATHER?

Ocean water and currents affect the climate. Because it takes far more energy to change the temperature of water than land or air, water warms up and cools off much more slowly than either. As a result, inland climates are subject to more extreme temperature ranges than coastal climates, which are insulated by nearby water. The ocean’s surface layer, so surface currents move a lot of heat, absorbs over half the heat that reaches the earth from the sun. Currents that originate near the equator are warm; currents that flow from the poles are cold.

• WHY DO STARS TWINKLE AT NIGHT?

Stars seem to twinkle or change their brightness all the time. In fact, most stars shine with a steady light. The movement of air (sometimes called turbulence) in the Earth's atmosphere causes the starlight to get slightly bent as it travels from the distant star through the atmosphere to us on the ground. Some of the light reaches us directly but some gets bent slightly. This gives the illusion of twinkling. Stars closer to the horizon appear to twinkle more than others. This is because the atmosphere is a lot denser near the horizon than between the Earth and a star higher in the sky.

• HOW DO WE KNOW ABOUT THE EXISTENCE OF PLANETS MILLIONS OF MILES AWAY FROM US?

Planets like Pluto in the outer reaches of our solar system can be viewed and photographed by powerful optical telescopes. Distant extra-solar planets, many light years away from our Sun, cannot be captured even by high resolution telescopes. Big planets orbiting close to a star can exercise a very small gravitational pull on the parent star. This causes a minute wobble in the rotation of the parent star which can be detected by highly sensitive spectroscope monitors. The existence of the planet can thus be only indirectly visualized.

• HOW DO ASTRONAUTS COMMUNICATE IN SPACE?

• HOW IS ZERO GRAVITY SIMULATED?

Simulation of zero gravity while still within the pull of the earth's gravity is achieved in a similar manner to that of a man-made satellite. When a body moves in a circular path, it experiences centrifugal force acting on it. This force points radially outwards and depends on both the speed and the radius of trajectory. Given this factor, if a plane flies in a circular arc trajectory, then passengers experience a centrifugal force pointing away from the earth. At a certain velocity, this force exactly counterbalances gravity, and passengers experience weightlessness or zero gravity.

• HOW MANY SATELLITES ARE CURRENTLY REVOLVING, AROUND THE EARTH?

Although anything in the Earth's orbit is technically called a satellite, the term is typically used to describe a useful object placed in orbit purposely to perform some specific mission or task. Approximately 23,000 items of space junk objects that were inadvertently placed in orbit or have outlived their usefulness are floating above the Earth. The actual number varies depending on which agency is counting. Pay loads that go into the wrong orbit, satellites with run-down batteries, and leftover rocket boosters all contribute to the count. This count is almost 26,000.

• WHY DO SOME PEOPLE HAVE 'RED EYE' IN PHOTOGRAPHS?

Light, usually from a camera flash, enters the subject's eyes and reflects it back into the lens. The red colour comes from the colouration of the retina which is lined with blood vessels. To prevent 'red eye', the feedback chain of light should be interrupted. The most effective way is to use indirect or off-camera lighting, which causes reflection from the eye to veer away from "^the lens. Another cure is to reduce the size of the pupils of your subject's eyes, effectively preventing the bounce-back syndrome. This is why some camera models fire one or more pre-flashes before taking a picture; the smaller flashes are meant to adjust the eyes to bright light, decreasing the pupil size.

• WHAT IS THE COMPOSITION OF SAND?

1. Sand is a non-cohesive, loose granular material which comes from rocks as a result of attrition of bigger rock pieces by water or wind in favourable weather conditions. The composition of sand depends   on   the   parent rock; the most common minerals being silica and feldspar. Less common minerals are iron. Silica comes in the form of quartz and feldspar consists of plagioclase. Additional mineral fragments are rare and include Muscovite, chlorite, epidote, garnet and zircon. Some deposits of sand may contain magnetite, glauconite or gypsum. Sands rich in magnetite are dark in colour, while those rich in gypsum have a green tinge.

• WHAT'S THE ORIGIN OF THE WORD MONSOON?

The word monsoon comes from the Arabic word mausim, which means weather. Owing to the yearly appearance of torrential rain, indicating a marked shift in weather, mausim gradually became monsoon.

• WHAT ARE FULLERENES?

Fullerenes are one of the three allotropes (same element in two or more forms) of carbon. The other two are diamond and graphite. Scientists Kroto, Smalley and Curl discovered fullerenes in Rice University in September 1985. One of the fullerenes — Buckminsterfullerene — consists of 60 carbon atoms linked together to form an almost spherical C60 molecule of joined hexagons (20) and pentagons (12). The bonds have the same arrangement as the panels on a football. Fullerenes can be prepared by passing an electric discharge through graphite rods in an atmosphere of helium. It is now known that a buckminsterfullerene is likely to be formed in sooty flames.

• WHAT IS MICROLENSING?

According to Einstein's Theory of General Relativity, light possesses mass. When light passes close to a massive object, it is attracted towards it and its direction changes towards it. Therefore, when an astronomical body is between the earth and another bigger, more distant astronomical object, the light coming towards the earth from the distant body gets focused on the earth because of the gravitational attraction of the intermediate body This is somewhat similar to focusing light from the sun on a piece of paper through a lens, and hence called astronomical microlensing. Astronomers use microlensing in their search for new planets, and to observe distant, faint objects and neutron stars.

• WHAT IS WATER MEMORY? ,

Water is said to have the power of memory — if certain chemicals are dissolved in water and then completely removed through a chemical process, the water may still retain some properties of the dissolved chemicals. Although this concept seems difficult to accept or comprehend, French scientist Jacques Benveniste allegedly proved it. However, other scientist could never replicate this experiment.

• WHAT IS THE DIFFERENCE BETWEEN SECOND GENERATION AND THIRD GENERATION TECHNOLOGY?

The main difference between second generation (2G) and third generation (3G) technology is data. 2G services were developed with mostly voice services in mind, but are capable of providing relatively slow (14.4kbps) speed data services. Most US service providers offer some data services, including limited wireless Internet access. For 3G, the data speeds are expected to be much higher; up to 2 mbps for fixed applications and 384 kbps for mobile applications. This will support advanced features including audio and video streaming, remote access to company databases, and a wider variety of entertainment and information services. 3G will also support a range of devices, including phones, personal digital assistants, and laptop computers.

• WHAT IS THE SIGNIFICANCE OF RED RAIN?

Five years ago, scarlet rainfall was reported in a town called Chenganacherry in Kerala's Kottayam district. Research scientists at the Mahatma Gandhi University in Kerala investigated this peculiar phenomenon and discovered that the rain contained cell-like particles, which they claim, are not from Earth but from outer space. The scientists conjecture that a comet that exploded over the sky caused the airburst that created the red rain

• WHY HORSE POWER IS CALLED SO?

When the steam engine began to do the work of horses in the mines during the early 1800s, the mine owners began to ask how many horses an engine would replace. James Watt, who invented steam engines, figured out a mathematical way to equate horses to engine power. Thus the term horsepower was invented. Watt measured the capability of a big horse to pull a load and found it could pull a weight of 150-pounds while walking at 2.5 miles per hour. This works out to 33,000 foot-pounds per minute or 550 foot-pounds per second.

• WHAT IS LIQUID OXYGEN USED FOR?

• WHO INVENTED THE ESCALATOR?

The basic mechanism of an escalator f was. first invented by Jess W Reno of 'the US in 1881. It was used mainly for riding on masts of wooden or iron poles in ships to fasten ropes or belts to support the sails. The name 'escalator' was applied to a moving stairway in 1900and first shown in a Paris exhibition. Charles Seeberger, with a company named Otis Elevator Company, built the first commercial escalator.

• WHY IS NASA'S DAWN MISSION SIGNIFICANT?

The Dawn Mission is important because it will study Ceres and Vesta, two of our solar system's largest asteroids in the belt between Mars and Jupiter. The spacecraft is scheduled for launch in July 2007 and will capture images of the surface of these asteroids and probe the composition, density and magnetism. The project almost got scuttled because of cost considerations but got a fresh lease of life recently

• HOW DOES THE GROUND PROXIMITY WARNING SYSTEM IN AN AIRCRAFT WORK?

Ground Proximity Warning System (GPWS) is designed to alert pilots if their aircraft is in immediate danger of Hying into the ground. Another common name is Ground Collision Warning System. Don Bateman is credited with inventing GPWS. This system monitors an aircraft's height above the ground as determined by the radio altimeter. A computer tracks these readings, calculates trends, and warns the captain with visual and audio messages if the aircraft exceeds certain thresholds or defined flying configurations also known as modes. The modes are: excessive descent rate, excessive .terrain closure rate, altitude loss after take-off, unsafe terrain clearance and excessive deviation below glidescope. Corrective action is then taken.

• WHAT IS A PYROMETER?

A pyrometer, invented by Josiah Wedgwood, is an instrument which measures relatively high temperatures, like that of a furnace. Many pyrometers work by measuring the radiation from the body whose temperature is to be measured. There is another device known as the optical pyrometer. It measures the temperature of glowing bodies by comparing them visually with an incandescent filament of known temperature. Another type is the resistance pyrometer in which a fine wire is in contact with the object and its temperature is determined by measuring its electrical resistance.

• WHAT IS WHITE COAL?

White coal is a form of fuel produced by drying chopped wood over a fire. It differs from charcoal which is carbonised wood White coal was used in England to smelt lead ore from the mid-16th to the late 17th centuries. It produces more heat than but less than charcoal and thus prevents lead evaporating. White coal was produced in distinctive circular pits with a channel, known as Q-pits They are frequently found in the woods 7f South Yorkshire.

• WHAT IS THE MEANING OF GEOSTATIONARY SATELLITE?

A geostationary satellite means a satellite, which moves in space at the same speed and in the same direction as the earth. As a result, its position is fixed in relation to any spot on the earth.

• IF THE SUN IS A STAR, WHY DOESN’T IT TWINKLE?

THE sun is an ordinary star. There are stars many times bigger than the sun. The stars that you see twinkling are so far away, that the light from them takes thousands of years to reach us. Even the light from the nearest star, Proxima Centauri, takes about three to four years to reach us. The light from the stars seems to twinkle because it comes through the constantly moving air currents around the earth. The sun does not twinkle because it is very close to us —just about 150 million kilometres away.

• HOW DID THE OZONE LAYER GET DEPLETED?

THE ozone layer got depleted because of chemicals released into the atmosphere by man, particularly chlorofluoro carbons used in the refrigeration industry and air conditioners.

• WHAT IS A TRANSDUCER?

A transducer is a contraption by instrumentation engineers to convert a physical action into an equivalent electrical signal.

• WHAT IS AN EXOTHERMIC REACTION?

Exothermic is an adjective pertaining to a chemical change that is accompanied by liberation of energy in the form of heat.

• WHAT ARE CONIC SECTIONS?

In geometry, circle, ellipse, parabola, hyperbola and a pair of straight lines are called conic sections as these geometrical entities can be obtained by slicing a cone.

• WHAT IS MARCODONTIA?

It is rare case of unusually large teeth found in otherwise normal person.

• WHAT IS RESIDUAL STRESS?

It is a stress in metal, on a microscopic scale, resulting from nonuniform thermal changes and plassic deformation.

• WHAT IS A GM COUNTER?

GM or Geiger-Mueller Counter is an instrument used in measurement of radioactivity. It is a cylindrical structure filled with inert gas and a central wire maintained at ultra-high voltage. The impinging radiationionises the inert gas and creates a shower a charged particles. This change can be electronic gadgets such as a computer.

• WHICH FLOWER IS KNOWN AS THE FLOWER OF THE NIGHT?

The flower of a type of cactus called orchid cactus, (Epiphyllum oxypetallum), is known as the "flower of the night" or the "queen of the night". This cactus is native to Central and South America. It possesses what appear to be flat leaves, which are actually stems, on which the flower blooms directly In Greek, "epiphyllum" means "upon the leaf". This cactus flowers once a year, and the flower opens only for one night. When the flower blooms, it fills its surroundings with a strong scent, and hence the name.

• WHAT IS GODEPS THEOREM?

Austrian-born American mathematician Kurt Godel proved that within a rigid logical mathematical system, there are certain questions that can neither be proved nor be disproved on the basis of the axioms of the system. Godel's theorem, in essence, goes beyond the realm of .

• DO YOU KNOW THE MEANING OF CHIRALITY?

If the mirror image of a natural object is different from the object itself, the object is called a chiral / objects. A perfect sphere is not chiral. Scientists are studying basic building blocks of matter to understand the fundamental reason for this amazing property.

• IS THERE ANYTHING YELLOW ABOUT THE YELLOW SEA?

The Yellow Sea is an arm of the Pacific Ocean that extends inland for about 400 miles between the east coast of China and Korea. The Chinese named this area the Huang Hal (Yellow Sea) because the waters along the banks are a yellow, muddy color. The Huang River carries deposits of yellow earth (huangtu) to the Yellow Sea, which thereby gets its name.

• WHAT IS BLACK ABOUT THE BLACK SEA?

The deep water of the Black Sea is supposed to be darker than the water of a normal sea, because the Black Sea has rich concentration of micro algae. Further, the Black Sea was called so in olden times, perhaps because it was very stormy and hence difficult to navigate. It was considered an inhospitable sea because barbarians occupied its shores. According to another theory, the Black Sea is called so because it is on the northern side of the Mediterranean Sea, and in ancient times the colour black was used in the compass to mark north.

• IS THERE ANYTHING RED ABOUT RED SEA?

The Red Sea is not actually red in colour. The Red Sea, located between the African coast and Saudi Arabia, contains a type of algae called Trichodesmium eythraeum. As they die, their remains end up on the ocean floor. THEIR COLOUR CHANGES TO REDDISH-BROWN AND THIS GIVES THE SEA A 'RED' COLOUR.

• WHAT'S UNIQUE ABOUT SPACE VEHICLE ORION?

Orion is the new moonship that NASA plans to develop. This was revealed when US astronaut Jeff Williams inadvertently mentioned the name of the vehicle while taping a message for a space agency when floating 354 kms above the earth in the International Space Station. It was transmitted by accident over space-to-ground radio.

• WHAT IS A PUFFER MACHINE?

A puffer machine, formally named an explosives detection trace portal, is a security device that detects explosives at airports and other sensitive facilities. The machine operates by releasing multiple puffs of air at a passenger standing upright in the machine. The cool air blasts are felt by the passenger, but are not painful or otherwise damaging. The purpose of the series of air blasts is to release microscopic particles into the air, such as gunpowder or residue from bomb-making materials, which would then be detected by the machine. If such particles are suspected, the passenger may be retained for further screening. The entire process takes approximately 15 seconds.

• WHY IS THE TRAJECTORY OF PLUTO DIFFERENT FROM ALL OTHER PLANETS?

The peculiarity of Pluto's trajectory is that both its eccentricity and inclination to the ecliptic, the approximate plane in which the orbits of the other planets lie, are extremely high. As Pluto was discovered only in 1930, astronomers haven't been able to fully explain the peculiarity of its orbit. A hypothesis proposed that it was originally a moon to Neptune, and later somehow escaped from Neptune's gravity In 1978, when Pluto's moon, Charon, was discovered, new theories were proposed regarding the origin of both Pluto and Charon. It is now believed that *both of them were formed independently, but after some time there was a collision between Pluto and the original Charon. From the debris of that collision,

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