Category Science

Who invented the computer mouse?

The computer mouse was invented by Douglas Engelbart in the 1960s, and patented in 1970. Dr Engelbart who died on July 2, 2013 also invented a number of other interactive information systems that helped make the computer a user-friendly tool. Before pioneers like specialized machines those only trained scientists could operate.

The computer mouse was popularised by its inclusion as standard equipment with the Apple Macintosh in 1984.

Why was it called ‘mouse’? The object’s shape and tail-like cord suggested the name.

A year after the mouse was invented, a researcher named Jack Kelley created the first mouse pad.

 

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What happens to the fish living in the lake?

Lakes in cold region freeze in winter. What happens to the fish and other animals living in the lake?

A lake may freeze when it is very cold but fortunately for the fish and other animals living in it, it freezes only at the surface. The water below the surface remains unaffected. This happens because of the odd behaviour of water. Like any substance water also contracts and becomes denser as it cools; but once it cools to 4  its behaviour changes. Below 4  water actually starts becoming lighter. At 0 , water freezes to ice. Ice is lighter than water and it floats on water. The ice layer insulates the water below from the cool air above. This keeps the water below the surface, warm and in liquid state.

 

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Can a magnet lose its power?

My friend had a small magnet and he warned me not to use it to pull things towards it too often as that would exhaust its magnetic powers.

Can a magnet become demagnetized by overuse?

In materials like iron, the atoms themselves are little magnets. In the natural or neutral state, these atoms all point in different directions. In a magnet, the atoms all point in the same direction.

To de-magnetise a magnet, the alignment of the atoms needs to be disturbed in such a way that they are pointing randomly in different direction, as in the neutral metal. This can be done in either of three ways:

(a) by heating the magnet over a gas flame.

(b) by hammering it for a few minutes, or

(c) by dropping the magnet from a height of over 100 ft.

The magnet cannot lose its magnetic properties due to over use.

 

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How does an underground train run?

The electric train gets electricity from an overhead wire. But how does a train running underground obtain electricity? The electric train has a device called a pantograph through which it draws electricity from a live wire above the tracks. In a suburban train 3 or 4 pantographs are used to run electric motors located in various compartments.

But in many underground train systems, the current is not obtained from an overhead wire. Instead, a third rail that runs parallel to the existing two, is laid and charged with electricity. The train picks up electricity from this track. This is done to reduce the height of the tunnel. In India, the Calcutta metro railway is an example of such an arrangement. Abroad, it is used in the London Underground.

 

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Can a machine run on its own forever?

My friend says his uncle has invented a machine that once started can run forever without any assistance or additional energy. Are there such machines?

Many scientists have tried to build perpetual motion machines but without success. The force of friction ultimately brings every moving thing to a stop. So far the only machine that comes close to being a perpetual motion machine, is an artificial satellite circling the earth. It circles the planet for years but ultimately friction with dust particles slows it down and it falls into the upper atmosphere where t burns up.

 

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Should the cheetah make a comeback?

India was once home to tens of thousands of Asiatic cheetahs. But overhunting and habitat destruction pushed the animal to the brink. In 1947, Maharaja Ramanuj Pratap Singh Deo of Koriya (now in Chhattisgarh) reportedly killed the last known Asiatic cheetah in India. In 1952, the cheetah was officially declared extinct in India.

But with the Supreme Court having cleared a proposal to introduce African cheetahs on an experimental basis, India may soon welcome a bunch of the spotted big cats from Namibia. But before that the authorities will have to identify a suitable habitat for the programme, assessing factors such as prey availability and the risks of human-cheetah conflict.

Among the sites that have been suggested for the relocation are the Kuno-Palpur Wildlife Sanctuary in Madhya Pradesh, the Velavadar National Park in Gujarat and the Tal Chapar Sanctuary in Rajasthan.

This is not the first time that the Indian government has tried to bring back the Cheetah. In the 1970s, officials tried to secure Asiatic cheetahs from Iran. But negotiations hit a roadblock after the Islamic Revolution of 1979 in Iran. (Today, Iran is home to the world’s last stand of Asiatic cheetahs-fewer than 50 individuals.) In 2001, scientists came up with a proposal to clone Asiatic cheetahs, but the plan fell through for various reasons.

The focus then shifted to importing African cheetahs, a distinct subspecies from the Asiatic cheetah, found in decent numbers throughout Africa. But this approach has received mixed reaction from conservationists and scientists. While some welcome it, others question the feasibility of the project.

ABOUT CHEETAHS

  • Cheetahs inhabit wide, open grasslands and arid habitats such as scrub forests.
  • They have a pale yellow coat with black dots on the upper part, while the underbelly is white. A cheetah can be identified by its spots and the black tear-like streaks on its face.
  • These cats have long tails, which enable them to balance while running fast.
  • The cheetah is the world’s fastest land mammals. It can reach a speed of 112km/h in just three seconds.
  • Cheetahs are carnivores and live off animals such as antelopes, rabbits, warthogs, springboks and birds.
  • They are usually found in groups, consisting of either a mother and her cubs, siblings or a group of males that live and hunt together.
  • The vast majority of cheetahs now live in Africa, while the Asiatic cheetah subspecies comprises a population numbering less than 50 in Iran and is considered critically endangered, according to the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species.
  • The population of cheetah is declining due to human-wildlife conflict, decline of prey, loss of habitat and illegal wildlife trade.

HOW CHEETAHS BECAME EXTINCT IN INDIA

Cheetahs are fast but docile by nature. These two traits sealed the fate of the animals in India. The spotted big cats had been hunted and captured indiscriminately since the 1500s. Kings across the country captured thousands of them from the wild to be tamed as trained to race and hunt animals such as antelope. The Mughal emperor Akbar is said to have kept 1,000 in his royal menagerie. But the inability of cheetahs to breed in captivity meant that wild cheetahs had to be constantly captured from their natural habitat. This led to a steady drop in their population. When the British colonists arrived in India, cheetahs were already scarce. For their part, the British degraded grasslands across India, leading to the cheetah’s eventual extinction in 1952.

THE DEBATE OVER THE CHEETAH INTRODUCTION PROGRAMME

Against

  • Conservationists believe that introducing African subspecies to India could affect their genetic make-up. Substituting one subspecies for other risks erasing valuable genetic adaptations, they say. African cheetahs may not be able to adapt to the grasslands of India.
  • India does not have the kind of grassland habitats it once had. They have been replaced by agricultural land or encroached upon by people over the past few decades.
  • The proposed habitats in India are not large enough to accommodate cheetahs and the areas do not have enough prey to sustain the big cats.
  • Some conservationists say that the plan to introduce cheetahs is a case of misplaced priorities. India should rather focus on conserving endangered species already living in the country instead of reviving an extinct species.

For

  • Proponents of the cheetah introduction programme are positive that African cheetahs can adapt to Indian condition.
  • They believe that the cheetah conservation programme could return the grasslands back to their past glory. While conserving the cheetahs, efforts will be made to save the grasslands ecosystem and biodiversity will be restored.
  • If cheetahs are introduced successively, India will be home to all of the big cat species in the Old World: tigers, lions, leopards, snow leopards and cheetahs.

 

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