Will Internet be used in space?

It certainly looks like internet will soon be used in space too. In fact, a programme of the United States Department of Defence called Iris will put an internet router in space by the start of 2009. This programme will allow voice, video and data communications for US troops using standards developed for the internet. Eventually, Iris could extend the net into space too. Right now data from satellites orbiting in space is beamed to the ground first, and then beamed up again to another satellite. Iris will make it possible for data to flow directly between satellites orbiting in space through the internet in space.

How can we talk through our hands?

Wouldn’t it be incredible if your hand could become a mobile phone? Well, sometime in the future, it may. A technology is already being developed called Finger Whisper technology, which could turn hands into handsets. By converting voice into vibration, then conducting vibration through the bones in the user’s hand, the hand becomes a type of receiver

What is VO WiBro?

This is another difficult sounding term which can be explained only if you know what WiBro is.WiBro is a wireless broadband internet technology being developed by the Korean telecom industry. With WiBro, Korean phones will tap into on ‘always on’ broadband connections that have a bandwidth much greater and faster than what is available now. Vo WiBro will be a great improvement on VoIP and the quality of service will be far superior due to the increased bandwidth and speed.

Why does a steel ball pitch higher than a rubber ball?

It is a scientific fact that the height to which any object bounces depends on its elasticity. This physical property is defined as the ratio of stress (The force acing on a unit area of the ball during compaction) created on the object to the strain (change in size of the ball) which acts on it. It is independent of the density of the material.

For larger values of elasticity, the strain should be smaller for a given amount of stress. In the case of a steel ball and a rubber ball, though steel has higher than rubber, it has greater elasticity, as the strain produced in steel is much less than that in rubber, for constant stress. In the case of a bouncing steel ball and a rubber ball, even though steel has higher density          than rubber, it has greater elasticity, as the strain produced in steel is much less than that in rubber, for constant stress. In the case of a bouncing steel ball, collision is elastic in which both momentum and kinetic energy are almost conserved.

            That is, the energy loss is minimum. Hence the steel ball bounces to a greater height than the rubber ball.


How is information stored in audio and video tapes?

Information is stored in audio/video tapes by magnetizing them. These tapes are actually long, thin plastic films coated with a magnetic material, mainly iron oxide.

Likewise, the player has a recording head which consists of a coil of a wire wound around a circular piece of iron with a small gap. Any current passing through the wire would produce a magnetic field around it.

Information (voice or image or any data) to be stored is converted into electric signals (by a microphone) amplified and fed to the recorder head. As the current varies in accordance with the image or sound (input signals) to be recorded, it produces a varying magnetic field.

When the tape is run through the small gap present in the recording head, the varying magnetic field magnetizes the particles on the tape rearranged their moments in accordance with the variation in the input signal.

To reproduce the signal recorded, the tape is again run past the recording/playing head which   senses the magnetic field along the tape. This induces a varying current in the coil. This current is amplified and fed to the speaker or TV to reproduce the original message.

What is the origin of gravity?

For a long time people have wondered what makes the planets go round the Sun and why anything thrown up comes down. Sir Isaac Newton probed the origin of this mysterious force and gave us the law of gravitation.

According to the law, which we have learnt in school, the force acting between two objects depends on their masses and the distance between them.

  The law makes it clear that the origin of gravity is the object itself- that is, by virtue of its own mass any object will have an influence on another object (mass). But if one were to ask why an object (mass) should exert a force on another, our present scientific knowledge does not provide a clear answer.

It seems that even Newton had thought about this question and tried in vain to get an answer. Finally he too admitted it is a god-given property to all objects.


What is brake horse power (BHP)? How is it different from the horse power (HP)?








 The term horse power was introduced by James Watt. He chose a normal horse and found that it could do a work of 33,000 ft-lb in a minute. He adopted this measure for comparing the performance of his engines.

  The actual power generated in the engine cylinder is called the indicated horse power (IHP). It is also defined as the power fed into the engine in the form of steam or calorific value of the fuel.

But all that power is not available to do useful work. This is because, part of it is used to overcome internal friction of the moving parts of the engine, work of charging, air resistance to flywheel rotation, and drive auxiliaries such as fuel pumps, governor, lubrication oil and water circulating pumps. This net power output of the engine is called brake horse power (BHP). It is 15- 30 per cent less than IHP.

The term brake horse power comes from the braking device used to measure the power output by stopping the engine.

 Thus it is the amount of power that the engine can produce at a certain speed (measured as rotations per minute).

Usually engines are rated with the help of dynamometers. The device has a power absorber, such as an electric generator or a water brake, which can put different loads on the engine. 

We are all familiar with the popping ears associated with takeoff and landing in an aero plane. This is caused by changes in pressure, but because the aircraft cabin is artificially pressurized, why i

For reasons of fuel economy, large civil transport aircraft have to fly at altitudes far in excess of those capable of sustaining life. Whereas 5,500 m is about the maximum altitude at which a person can live for any extended period, a subsonic passenger jet has the best fuel economy when flying at around 12,000 m.

Aircraft manufacturers therefore, have no choice but to pressurize the interior of a passenger aircraft. This poses huge technical problem. At 12,000 m, where the pressure is about one-fifth of that at sea level, the pressure inside is trying to burst the fuselage apart. This pressure has to be contained and all the stretching and flexing of the fuselage during a flight has to be kept within safe limits.

It is far easier to do this - if the pressure differential between inside and outside is kept to a minimum, a cheaper and lighter fuselage structure can be used.

For civil airliners this means that the pressure inside during cruising is kept at the lowest possible safe level - 2500 m. This is about the maximum altitude which a normal healthy person can be subjected to without ill effects.

 Even so, unfit people, those with respiratory illness and those who have sampled a few too many duty-free drinks might still feel ill, even at this altitude.

There is another problem: all airfields are not at the same altitude. In an extreme case, a flight from Heathrow in England to La Paz in Bolivia would entail going from sea level to around 5200 m, where the air pressure is about half that at sea level. Under these circumstances it is just not possible to maintain the same pressure throughout the flight. Imagine what would happen if the pressure inside and outside were not the same at the time the doors were opened: the effect would be quite spectacular and most undesirable.

As for the ear popping, nowadays, for your safety and comfort the internal pressure is imperceptibly reduced, all under computer control, as the aircraft climbs. It is gradually increased during descent so that, as the aircraft is coming to a stop on the runway, the pressure inside and out is the same. This is normally sufficient for your ears to adjust, but if all else fails, pinch your nose and gently but firmly increase the pressure in the nasal cavity until you feel the pressure equalize.


Why does a spinning top reverse its direction of rotation towards the end?

A spinning top process (or rotate) about its central axis due to the lateral forces given initially or due to lack of speed (as during the end of spinning). When the speed becomes too low (not zero) for it to hold it (its mass) upright, it falls down.

 As the body of the top touches the ground, due to friction it is unable to spin and so the remaining spin (force) forces it to roll on the ground, obviously in the opposite direction.

 Due to tapering shape of the top, it tends to rotate along a circle in the reverse                                                                                             direction, with the nail pointing towards the                                                                                    centre.

What are the flags and badges used by the Indian Army?

and campaign The army normally flies the flag of the headquarters, formation, or other unit at the headquarters building and the commander’s residence. The national flag is displayed at all posts for ceremonies in connection with Republic Day and Independence Day.The Indian war flag is red with the golden lions of Sarnath, and golden crossed swords. The flag of Chief of the Army Staff of the Indian Armed Forces is red in colour with the national flag in one corner, the golden Loins of Sarnath and golden crossed swords. Field Marshals have red flags with crossed batons surrounded by a lotus flower wreath. The Asoka Lion’s emblem is above the wreath, and there are five stars below, all in yellow. The army also has different badges for different regiments, as well as gallantry medals.



Why are national flags so important?

It is important to note that a national flag tells the world about a country, its people and their history. It symbolizes its culture and its heritage. A national flag reminds its citizens where they came from, where they are and their duty to the future. It is well known across the length and breadth of the country, and inspires patriotism in its citizens, for it is steeped in history and tradition.




                                                                                                                                                                                                                                                                                                                                                                  India’s national flag

Do the colours of a flag have special meaning?

Yes they do. White is associated with peace and honesty. Yellow is a symbol of generosity and red represents bravery, strength and velour. Blue stands for vigilance, truth and justice, while green are a symbol of hope, joy and divinity. Black sometimes stands for determination. However, a plain black flag is a symbol of mourning. Flags flown at half mast also denote mourning.Our national flag is made up of three colours – saffron, white and green. The saffron stands for courage and sacrifice; the white, for purity and truth; the green for growth and auspiciousness. In the centre of the white band there is a wheel in navy blue to indicate Dharma Chakra. It is a Buddhist symbol dating back to 200 BC.You must always show respect to the flag, and never use it for anything else except as a symbol of our great nation and culture.

What is the difference between badges and flags?

Badges can be part of our everyday life. When you go to school, you remember to pin your school badge on your uniform. Your father may also wear a badge when he goes to work. A badge is something that you wear to show who you are, to which institution you belong, or what your rank is. It may also be reward for something you have achieved, or a sign of your authority.Badges are of great importance in the military. Everyone wears one to show his or her rank, and also signify any special training received and record note worthy achievements. Policeman wears badges to show their authority, and members of a club may wear a badge to show that they belong to a particular club or group. Sometimes badges are worn as a sign of protest, and sometimes as sign of mourning, like the black badges worn when someone dies   Badges can be made of many different types of materials… cloths, metal, plastic, rubber or leather. Some badges are quite beautiful and collecting badges can be an enjoyable hobby.  


Flags are rectangular pieces of cloth with a distinctive design. They are always flown from masts or poles. National flags are symbols of a nation and must be always given respect. Flags are important in the military where they are used to coordinate actions of different units and avoid confusion. A ship at sea flies a flag to identify itself, and the navy uses flags extensively for signaling Originally, flags were used primarily in warfare. To some extent, they remain a symbol of leadership, serving for identification of friend and foe, and as rallying points. Flags are now also extensively used for signaling, for decoration, and for display.  A person who is chosen to carry a flag during any ceremony is called a flag bearer. It is a great honour to be selected as a flag bearer, whether it is your school flag, or the national flag.


                                                                                                                                                                                          Military Badges


Signal at sea

Flags have long been used to identify a ship’s nationality and to convey clear messages. Flags of different patterns and colours form an internationally recognized code for the letters of the alphabet and each also has a meaning of its own when flown individually. They are shown below.








International code                                                                                                                                             

A: I am undergoing speed trials.

B: I have explosives on board.

C: Yes.

D: Keep clear, I am in difficulties.

E: I am altering course to starboard.

F: I am disabled.

G: I require a pilot.

H: Pilot is on board.

I: I am altering course to port.

J: I am sending a message by semaphore.

K: Stop at once.

L: Stop, I wish to communicate with you.

M: A doctor is on board.

N: No.

O: Man overboard.

P: (The Blue Peter): I am about to sail.

Q: Quarantine flag.

R: I have stopped.

S: I am going astern.

T: Do not pass ahead of me.

U: You are in danger.

V: I need help.

W: Send a doctor.

X: Stop, and watch for my signals.

Y: I am carrying mails.

Z:  I am calling a shore station.


What are traffic signals?

Can you imagine the confusion on our roads if there were no traffics signs or signals? Traffic signs and lights are important in that they give directions to people, warn us of dangers, control speed, and enforce traffic rules. Traffic lights are usually placed at the intersection of roads. They indicate when it is safe to drive, ride or walk. Everywhere in the world, a red traffic light means ‘stop’ and green light means ‘go’.Road signs were the first traffic control devices to direct travelers on their journeys. Today, road signs have many different purposes. Some have arrows showing the direction in which to go. Others have a slash inside a circle – a warning that certain vehicles and certain actions are not allowed Road signs also remind us of the speed limit, and give details about the road surface. They tell us when schools, hospitals and petrol bunks are nearby, and indicate dangerous turns on the road. It is important that we all learn the meaning of these road signs and traffic signals, so that accidents can be avoided, and we can have safe and comfortable journrys.