Can vehicle tyres be filled with liquid instead of air?

Vehicles are filled with air to absorb the shocks generated as the vehicle moves on uneven roads, and make the ride comfortable.The shock absorbing capacity is present by the fundamental property of air i.e compressibility - air can be compressed to smaller volumes on application of pressure.

But liquid is not compressible and so if one uses it to fill the tyres, all the shocks generated on the tyres will be completely passed on the vehicle and its passengers will feel the discomfort.In addition liquid filled tyres increase the rolling resistance  of vehicles because of the increase in weight. Hence a part of the engine's power and fuel is wasted in overcoming this resistance.

What is ozonised mineral water?

Ozone is a blue gas with a relative molar mass of 48 and molecular formula of O3.It converts into oxygen after oxidizing process is complete.Ozone is the ultimate Eco-friendly disinfectant. Like when drinking water is treated with Chlorine (which is found to be highly carcinogenic chemical) ,the residual chlorine is consumed with the water.On the other hand residual ozone,having a half life of only 20 minutes reduces to oxygen, leaving behind pure and safe drinking water.
Another added advantage of using ozone is that it destroys all the micro organisms leaving behind colourless and odourless water.
Ozone generators produce ozone by passing oxygen through electric field.This ozone is bubbled through the water to be treated in a specially designed apparatus with controlled rate of injection.The amount of ozone diffused in water is directly proportional to the contamination of water.  

Why is fire hot?

Chemical reactions can be either exothermic(heat liberating) or endothermic(heat absorbing).Oxidation reactions are exothermic and reduction reactions are endothermic. Combustion is an oxidation reaction and hence is exothermic.
                                                 
All liquid, solid, and gaseous fuels contain any one of the three combustibles constituents viz. carbon, hydrogen, and sulphur. When fuel is burnt the heat liberated makes the products of combustion hot. The products of combustion are carbon dioxide, water vapour and sulphur dioxide. Along with these, the unused oxygen in the atmospheric air supplied for combustion and also the entire quantity of nitrogen which is the major constituent in the air are also heated. That is why fire is hot.

How does ballast-less track provide safe travel?

Ballast is a prime component of the track that acts as a vibrant medium to transmit from the rail surface the weight of the train down to the formation, the wells set on prepared terrain. It ensures a cushioned and smooth run for the train and precludes the longitudinal displacement of the rail called creep. In ballast-less track, as the name suggests the ballast is replaced by a bed of concrete.
          The rails rest on rubber pads placed over concrete sleepers, which are fixed on the concrete bed. The ballast-less track helps to eliminate the evils of dust and noise pollution and proves suitable for underground railway also. So it is also safe for travel.

Like ordinary paints do metallic paints also fade?

Metallic paints do fade. It depends on the quality and the type of the aluminium paste used. Usually in most of the metallic paints, the commonly used pigment is aluminium pigment in the form of paste. Two types of aluminium pigments are available in the market. One is leafing, and the other is the non-leafing aluminium pigment will not get dispersed (or dispersed partially) with the resin while mixing, whereas the non-leafing will get completely dispersed with the resin during mixing.
            So, if the metallic paint contains the leafing aluminium pigment it will get faded over a period of time, whereas if it contains a non-leafing aluminium pigment it will not fade for a longer period.Example: The street lampposts on the roads and highways which are coated with metallic paints appear dull after a short period of coating, whereas cars coated with metallic paints shine even after a long time.

Why do runners run in anti-clockwise direction?

As the heart is on the left side, for humans and animals, running anticlockwise makes the centrifugal force of the body to act from left to right.Whereas it is from right to left for clockwise running.
        Superior venacava (the principal vein carrying blood to the heart) takes blood to the heart aided by heart suction.This vein carries blood from left to right.
        Centrifugal force due to anticlockwise running helps this suction.If we run clockwise, the centrifugal force impedes suction. That is why, in olden days, health officers ensured that all carnival merri-go-rounds were run only in the anticlockwise direction.
        Racing tracks, animal shows in circuses, bullock-drawn pelton wheels, all mostly have only left turns. Stairways in temple towers have only left turns for going up. Clockwise running tires people, especially, children, easily.

What is the principle of photo-chromatic glasses?

Photo-chromatic glasses become dark (activated) when kept under bright light especially when the wavelength of the incident light is in the range of 320-400 nm(nanometres).Darkened glasses get bleached when kept in the dark or under light of longer wavelenghts, 550-650 nm.Both these processes occur simultaneously during daylight and the glass's transparency depends on the predominant reaction taking place in it.
                     These processes are based on the possibility to split and recombine silver and chloride ions in silver chloride using light of different wavelenghts.It is the same principle which is used in photography also. However, in photography, the chlorine and silver ions are separated and not allowed to recombine. In photochromatic glasses, the chloride ions cannot diffuse far away from the silver ions as they are held tightly in a glass matrix. Hence when the 'activating energy' is withdrawn, they recombine to form silver halide. The speed(or rate) of the reaction depends on the doping level of the halide with a catalyst(cooper).
                   Choice of the halides, crystals' size (usually 40-100 Angstroms), concentration, glass type and sensitising dopants are all factors that decide the final behaviour of photochromatic glasses used in light-control, displays, memory applications and optical data processing.

In what way are spatial sound, wide sound and surround sound different from stereo sound?

Let's look at at the way a home music system work.The standard format for home music systems (or FM radio or even television) is the two-channel sound,which is otherwise known as Stereo sound.It is nothing but the two-channel recording,in which sound is played on speakers on either side of the receiver/listener.In the broader sense,stereo effect just recreates the experience of being present at the event.
          Surround sound refers to multi-channel systems.To be more specific, multi-channel systems designed by 'Dolby Laboratories'.It also refers to home theatre multi-channel audio systems, in which sound originates from multiple directions.
         Spatial sound is very much concerned with the concept of localisation.Humans and animals as well hear sound in three dimensions and the very fact is that the perception of spatial aspects of sound is essential to our survival.That is, Spatial waves or sound are well recognised by person since his ear-body-brain combination correctly decodes waves. Assume you are listening to a recorded sound where there is a lack of sensational ambiance, a separation of the instruments and a perception of context of the performance.
        A keen observation reveals that something is missing here. Yes. The missing stuff happens to the Spatial effect or detail. To quote an example, both Virtual Reality (VR) and High Definition Television(HDTV) require spatial sound reproduction apart from what ordinary stereo can offer.But there remains no proof that no commercially available system can successfully convey the natural spatial hearing experience or effect.
       Wide sound is more or less similar to Surround sound. To be more precise, it's a type of sound that is intermediate between stereo and surround effect. The frequency range lies between that of stereo and surround ones.

How does a compact fluorescent lamp consume less electricity than conventional fluorescent lamps and bulbs?

Fluorescent lamps are based on the phenomenon of gas discharge between two electrodes at the ends of the glass tube.Generally these tubes contain a little mercury in the low-vapour phase.When sufficiently large voltage is appiled between the electrodes,some atoms of the vapour get ionised.
The process of ionisation starts with stray electrons and ions that are generally present in the vapour.The electron-ion pair so formed gets accelerated towards electrodes of opposite electrical polarity,gaining kinetic energy.When they collide neutral mercury atoms,some of them are ionised and some are electronically exicted.Excited atoms release their energy in the form of electromagnetic radiation,part of which is in the visible and in the infrared regions of the spectrum.But it is rich in the visible ultraviolet region.
         A fluorescent light source has the inner surface of its glass tube painted with a material called phosphor.Zinc sulphide is the commonest example of a phosphor.But phosphor used in particle are complex mixtures of the sulphides and phosphates of barium,strontium and rare earth elements.These phosphors have the property of absorbing ultraviolet component of the radiation and re-emitting a major fractrion of the corresponding energy in the form of visible light.This enhances the lamp's efficiency of converting electrical energy into visible light.
         The ordinary fluorescent lamp works with a supply voltage of about 220 volt.Since the start of the discharge process demands a little higher voltage,it also employs a starter and ballast(a choke coil) that together produce the desired voltage.On the other hand, the compact tube works at about 400 volt(constant), which is produced by a transformer arrangement embedded in its base.
         Higher efficiency means low consumption of electrical energy.A filament lamp has the lowest efficiency, because is is based on the fact that a material body heated to a high temerature emits radition of all wavelenghts.This radition is richer in the infrared part of the spectrum and since there is no mechanism of converting this into visible light, it has poor efficiency.The three types of lamps may have a typical efficiency ratio of 8:6:3.

Why does a mushroom shaped cloud form after a nuclear bomb explosion?

When a nuclear weapon explodes,there is a rapid release of a large amount of energy within a small volume.This results in significant increase in temperature and pressure.The temperature may be a few tens of million degrees and pressure a few million times the atmospheric pressure.At this temperature,all the material present in the weapon will be converted into hot compressed gases.
Within a fraction of a millionth of a second of the explosion, the weapon's residues emit large amounts of energy mainly in the form of X-rays.The surrounding atmosphere absorbs this energy.This results in the formation of a blazzing, highly luminous, spherical mass of air and gaseous weapon residue called the fireball.
             Within an extremely short time after the explosion,the fireball from a high yield nuclear weapon will be about 130 meters across increasing to about 1700 meters in ten seconds.The fireball expands rapidly engulfing the surround air.
             The ball of hot air is less dense than the surrounding air.It rises swiftly like a hot air balloon.This rising column pulls up debris of the weapon,dust and moisture along with it forming cloud.As it moves up,it cools gradually and reaches about 10km where the atmosphere is extremely stable.The ball of air mass moving up does not have enough energy to penetrate this stable layer.It flattens out.As the relatively warmer layers at the bottom push up,the top layer spread laterally and equally in all directions and the cooler denser layer descend at he edges,giving a distint mushroom shape.
    

Why are all the planets in the universe spherical in shape?

Dip a finger into a bowl of water and then take it out.Now watch the drop of water as it trickles down the finger and drops down. You will notice that the drop of water acquires a spherical shape.Place a drop of mercury on a smooth surface.It attains a spherical shape,this phenomena is due to the cohesive force (force of attraction between the molecules of same element) which brings the molecule closer.
               But then why does it take a spherical shape, why not a cubic one? This is because, out of all multidimensional geometric figures, sphere has the least surface area. Thus all particles try their best to attain a spherical shape in order to reduce their surface area. It is for the same reason that when you pour any liquid in space they attain a spherical shape. But this is not the case with solids since their molecules are compactly packed and cannot be displaced. When a new star is born the gas clouds around it condenses   to form planets. The dense gas passes through three states, the gaseous state , the molten state and finally the rigid solid state. When a planet is in the first two states it attains a spherical structure due to the cohesive force as mentioned in the illustration. Later the molten planet solidifies into a rigid planet like Earth.

What is RDX?

RDX, widely used as an explosive and as a base charge for detonators,is the British abbreviation for Research Department Explosive or Royal Demolition Explosive . Chemists call it by various names such as cyclo-tri-methylene tri-nitramine, 2,4,6 tri-nitro N-methyl aniline, tetryl, hexa-hydro-1,2,3-trinitro-5-triazine, hexagon, T4 and cyclonite.
             RDX is odourless and so it can not be detected by conventional devices.Unlike other explosive, it carries fuel and oxidiser in the same molecule.On detonation it creates a powerful blast that sends out shock waves.It is used as energy boosting explosive in double base solid propellant where smokelessness is an advantage.
             RDX is prepared by reacting hexamethylene tetramine or its dinitrate salt with nitric acid.The famous Bachman process uses hexamine, nitric acid,ammonium nitrate and acetic anhydride.RDX can be easily moulded into any shape,for example, like a long thread or a sheet, and that is why it comes in handy for terrorists.

Is it necessary to change the water in an aquarium periodically?

Like all other creatures fishes too need oxygen for breathing.But unlike other creatures fishes respire by their pair of gills.Their gills separate the oxygen from water and release out carbon dioxide.In lake or pond there is not much considerable change in the Oxygen level because: in a huge amount of water only negligible ratio of oxygen is used.Direct and indirect rainwater keeps the oxygen ratio stable.
          Water plants like Hydrilla and Vallisneria use the carbon  dioxide and deliver oxygen during their photosynthetic activity.But in the aquarium there is less amount of water and there are no natural plants to maintain the oxygen level.Another reason for changing the water is to keep the water clean from fish waste in aquarium.

Why solar eclipse should not be viewed with naked eyes?

One should not see the Sun during eclipse as the sudden change in light intensity may damage the eye.The human eye, as a protective measure, can adjust automatically to varying light conditions-under bright illumination, as during the day, it closes partially and under dark conditions,as in the night,it opens fully.However this process of adjustment takes some time, a few minutes.

As it is dark during a total solar eclipse, the eyes is fully open to let in more light.After totality, as the sun emerges the increase in light intensity is so sudden that it catches the eye unawares.Being very bright it can damage the retina even in few seconds.

Does the sun rotate?

Yes, the sun too rotates about its axis.But unlike the earth, which has rotation period of one day, the sun has a 'differential rotation'.i.e.All the parts of the sun do not have the same period of rotation.The period of rotation near its equator, sun spot zone, and pole are 26.9, 27.3, and 31.1 days.

The sun's enormous core temperature of 15 million degree Kelvin and a surface temeprature of 6,000 degree Kelvin, leaves all its constituents in the state of a high pressure, gaseous  plasma.For the purpose of certain calculations, the top and the bottom ends of the visible sphere of the sun are designated as north and south poles respectively.

Photographs are taken daily and the movements of the spots, filaments and plages are observed for various latitudes and longitudes, for a long period of time.From this, the sidereal rotation period is calculated.The reason behind this phenomenon is still a puzzle to solar physicists.

Why do we have sodium vapour lamp in the streets and not mercury vapour lamp?

White light consists of seven colours-VIBGYOR.During foggy days,air is highly humid and contains lots of tiny water droplets which can act like a prism.So, if white light is used in automobile headlights and street lamps, water droplets will split it into its componet colours, thereby, creating a circular rainbow around each light source.This will affect clarity of vision and lead to acccidents.In order to avoid this effect, a monochromatic(yellow) light source is used.Yellow is chosen because, being in the middle of the visible spectrum, it undergoes medium refraction and medium reflection while passing through a water droplet.Also, it is next only to whilte in brightly illuminating all objects in their original colour.

However, mercury vapour lamps are used in the interiors because, white light is more pleasing to our eyes, and slight reduction of vision due to fog is not of great concern.

What is the difference between a hydrogen and an atom bomb?

An atom bomb is a fission device.Here a heavy atom (like uranium) is split into two or more lighter atoms.In such a nuclear fission process, one or two neutrons are also released from each atom.If these neutrons are captured bythe surrounding heavy atom, further fission takes place leading to further neutron release.In atomic power reactors, this chain reaction is controlled so that the energ released during the reaction can be used beneficially.

But in the case of an atom bomb, the chain reaction is not controlled but left free.This leads to the release of large amount of heat energy in a very short time resulting in a catastrophic explosion.

In a fusin bomb, such as a hydrogen bomb, two or more lighter atoms fuse together to form a heavier atom.Such fusion reactions can take place only at very high temperature, say a few million degrees Celsius.Only at such temperatures can the starting atoms overcome the repulsive forces acting between them.

In this case also, when uncontrolled fusion takes place a large amount of energy is suddenly released resulting in explosion far bigger than an atomic explosion.

It may be noted that the temperature needed to initiate a fusion reaction is normally obtained by a fission reaction.

What is red eye reduction and its function?

Many Compact cameras and some SLR cameras have built-in flash.The flash cannot be detached from these cameras and may result in "red eye" that is,the pupils of a subject's eyes appear red in coloue photographs.

Red-eye occurs when the light from the flash is reflected off the back of the retina.Subjects pupils are dilated and the On-Camera flash actually illuminates the blood vessels in the eye.The only way to avoid this is to close down the pupils i.e.contract the iris by raising the room lights,or using "red eye reduction flash mode".

This feature is available in sophisticated compacts.This mode fires a pre-flash or a bright lamp prior,thereby reducing the affect.In compacts where there is no red-eye reduction feature,the following technique may be employed to reduce the red-eye effect.The flash light may be bounced off the ceiling or wall,before it reaches the subject.

Why should we not sleep north-south?

Researchers at the Chennai Institute of Magnetobiology,say that sleeping in the north-south direction could make one lack a sense of well being at times.According to Dr.Sankaranarayanan,director of the institute,when a man lies with his head towards north in a pulsating magnetic field,his brain's electrical activity is suppressed or damped.Measurements reveal that blood circulation in fingure tips are affected and the balance between neurochemicals is upset.In addition,it gives subjective experiences like headache,confused thinking and lack of a sense of well-being.
     
As opposed to this,he says,if one sleeps east-west,in the pulsed field,the brain's activity is considerably enhanced.Also,the peripheral blood circulation all over the body is enhanced.Hence he feels relaxed and alert.

It is known that the Earth's magnetic field pulses at extremely low frequencies and is typically in the range of human brain's electrical activity.These pulses are not present always but they peak during certain periods generally associated with solar activity.If one sleeps north-south during such activity headache,general discomfort,nausea and confusion may result.On inactive nights,there may not be any change in the body,he says.

Why are aeroplanes not affected by lightning?

Clouds are made of water droplets and dust in the atmosphere at altitudes of 1 to 16 km.While traveling through air,due to friction,the water droplets get electrically charged.Lightning occurs due to sparking between oppositely charged clouds-a high voltage spark rushes towards the ground(at zero potential) through moisture-filled air.

If any ground based structure is on the path of the spark,the top of that structure is excited to a high electrical potential while its bottom (in contact with the ground) remains at zero potential.This high potentail difference sets a very high current in the structure causing sudden heat generation in the material and destruction.But in flying aeroplanes,there is nothing like a ground point which remains always at zero voltage.

Hence even if hit by a lightning,the plane's entire surface acquires the same high potential and due to lack of potential difference there is no current and hence no destruction.