Science For You

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Science For You is the 1000 th topic at General discussion.

Share your science knowledge and doubts on this thread.

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Electron

The electron is a fundamental subatomic particle that carries a negative electric charge. It is a spin ½ lepton that participates in electromagnetic interactions, and its mass is approximately 1 / 1836 of that of the proton. Together with atomic nuclei, which consist of protons and neutrons, electrons make up atoms. Their interaction with adjacent nuclei is the main cause of chemical bonding.

The discovery that the electron was a subatomic particle was made in 1897 by J.J. Thomson at the Cavendish Laboratory at Cambridge University, while he was studying cathode ray tubes. A cathode ray tube is a sealed glass cylinder in which two electrodes are separated by a vacuum. When a voltage is applied across the electrodes, cathode rays are generated, causing the tube to glow. Through experimentation, Thomson discovered that the negative charge could not be separated from the rays (by the application of magnetism), and that the rays could be deflected by an electric field. He concluded that these rays, rather than being waves, were composed of negatively charged particles he called "corpuscles". He measured their mass-to-charge ratio and found it to be over a thousand times smaller than that of a hydrogen ion, suggesting that they were either very highly charged or very small in mass.

Electrons have an electric charge of −1.602 × 10−19 C, a mass of 9.11 × 10−31 kg based on charge/mass measurements equivalent to a rest mass of about 0.511 MeV/c². The mass of the electron is approximately 1/1836 of the mass of the proton. The common electron symbol is e−. The electron is thought to be stable on theoretical grounds; the lowest known experimental upper bound for its mean lifetime is 4.6×1026 years.

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Robot

A robot is an electro-mechanical system which can move around, operate a mechanical arm, sense and manipulate their environment, and exhibit intelligent behavior, especially behavior which mimics humans or animals. The word robot can refer to both physical robots and virtual software agents, but the latter are usually referred to as bots.

The first digitally operated and programmable robot, the Unimate, was installed in 1961 to lift hot pieces of metal from a die casting machine and stack them. Today, commercial and industrial robots are in widespread use performing jobs more cheaply or with greater accuracy and reliability than humans. They are also employed for jobs which are too dirty, dangerous or dull to be suitable for humans. Robots are widely used in manufacturing, assembly and packing, transport, earth and space exploration, surgery, weaponry, laboratory research, and mass production of consumer and industrial goods.

A typical robot will have several or possibly all of the following properties.

* It is artificially created.
* It can sense its environment, and manipulate or interact with things in it.
* It is programmable.
* It moves with one or more axes of rotation or translation.
* It makes dexterous coordinated movements.
* It moves without direct human intervention.
* It appears to have intent or agency.
* It has some ability to make choices based on the environment, often using automatic control or a pre-programmed sequence.

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History

Many ancient mythologies include artificial people, such as the mechanical servants built by the Greek god Hephaestus (Vulcan to the Romans), the clay golems of Jewish legend and clay giants of Norse legend, and Galatea, the mythical statue of Pygmalion that came to life.

In the 4th century BC, the Greek mathematician Archytas of Tarentum postulated a mechanical steam-operated bird he called "The Pigeon". Hero of Alexandria (10–70 AD) created numerous user-configurable automated devices, and described machines powered by air pressure, steam and water. Su Song built a clock tower in China in 1088 featuring mechanical figurines that chimed the hours.

Al-Jazari (1136–1206), a Muslim inventor during the Artuqid dynasty, designed and constructed a number of automated machines, including kitchen appliances, musical automata powered by water, and the first programmable humanoid robots in 1206. The robots appeared as four musicians on a boat in a lake, entertaining guests at royal drinking parties. His mechanism had a programmable drum machine with pegs (cams) that bumped into little levers that operated percussion instruments. The drummer could be made to play different rhythms and different drum patterns by moving the pegs to different locations.

The first truly modern robot, digitally operated and programmable, was invented by George Devol in 1954 and was ultimately called the Unimate. Devol sold the first Unimate to General Motors in 1960, and it was installed in 1961 in a plant in Trenton, New Jersey to lift hot pieces of metal from a die casting machine and stack them.

There were more than one million robots in operation worldwide in the first half of 2008, with roughly half in Asia, 32% in Europe, 16% in North America, 1% in Australasia and 1% in Africa.

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Dangers and fears

Fears and concerns about robots have been repeatedly expressed in a wide range of books and films. A common theme is the development of a master race of conscious and highly intelligent robots, motivated to take over or destroy the human race.

(See The Terminator, Runaway, Bladerunner, Robocop, the Replicators in Stargate, the Cylons in BattleStar Galactica, The Matrix, and I, Robot). Some fictional robots are programmed to kill and destroy; others gain superhuman intelligence and abilities by upgrading their own software and hardware. Another common theme is the reaction, sometimes called the "uncanny valley", of unease and even revulsion at the sight of robots that mimic humans too closely. Frankenstein (181, often called the first science fiction novel, has become synonymous with the theme of a robot or monster advancing beyond its creator.

Manuel De Landa has noted that "smart missiles" and autonomous bombs equipped with artificial perception can be considered robots, and they make some of their decisions autonomously. He believes this represents an important and dangerous trend in which humans are handing over important decisions to machines.

Marauding robots may have entertainment value, but unsafe use of robots constitutes an actual danger. A heavy industrial robot with powerful actuators and unpredictably complex behavior can cause harm, for instance by stepping on a human's foot or falling on a human. Most industrial robots operate inside a security fence which separates them from human workers, but not all. The first fatality involving a robot was Robert Williams, who was struck by a robotic arm at a casting plant in Flat Rock, Michigan on January 25, 1979. The second was 37 year-old Kenji Urada, a Japanese factory worker, in 1981. Urada was performing routine maintenance on the robot, but neglected to shut it down properly, and was accidentally pushed into a grinding machine.

Robots

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Science Quiz

Name the insect which carries the parasite that causes sleeping sickness.
Tsetse Fly

What are the larvae of house-flies called ?
Maggots

What is the name given to the resin produced by lac insect ?
Shellac

Which animal forms connecting link between Annelid and Arthropoda ?
Peripatus

What are the larvae of butterflies called ?
Caterpillar

What do you call a segment of tape worm ?
Proglottids

What is the function of flame cells ?
Excretion

In Zoology, what kind of animals are called Apivorous ?
Bee-eating animals

What is the name of the larva of sqilla ?
Alima

What is the host of Taenia Saginata ?
Cow and Buffalo

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What is the common name of Dentalium?
Tusk shell

Name the anticoagulant present in leech.
Hirudin

Name an animal that contains chlorophyll.
Euglena

What is the name of insect which is commonly found in our houses behind pictures on walls and amidst books causing damage to them ?
Ctenolepisma species

Which animal is commonly called as Devil fish ?
Octopus

What is the biological name of praying mantis ?
Mantis religiosa

What is the common name of sepia ?
Cuttle fish

Which sea animal is considered as a link between the vertebrates and invertebrates ?
Amphioxus

Flying fish are fish, but flying foxes are not foxes. What kind of creatures are they?
Bats

Which order of mammals reproduce eggs but suckle their young ?
Monotremes

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What is the branch of Zoology dealing with whales called ?
Cetology

What is the fat of whale called ?
Blubber

Cypselurus are called flying fishes. What are syngnathus called ?
Pipe Fishes

What are the cold blooded vertebrates that live both on land and in water called ?
Amphibian

Which bird has no wings at all ?
Kiwi

Name a reptitle which can change the color of its skin.
Chameleon

What is the name of an extinct bird which shares the characters of both reptiles and aves ?
Archaeopteryx

Which reptiles are called 'limbless lizard' ?
Snakes

Which animal is called 'ship of desert' ?
Camel

What name is given to a camel with two humps ?
A Bactrian

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What is the common name of pterapus ?
Flying fox

What is the zoological term of leopard ?
Panthera pardus

Name the largest animal in the world ?
Blue whale

Name fish which is called as sea-horse.
Hippo campus

What is the zoological name of cat ?
Felis dometicus

What is the biological name of Indian Cobra ?
Naja Naja

Name the process by which plants prepare their food.
Photosynthesis

What are seedeels plants called ?
Cryptogams

Name the instrument used to measure root pressure.
Manometer

Provide the technical term form the cultivation of fruit trees.
Arboriculture

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What is the other name of root cap ?
Calyptra

What is the term used for the occurrence of more than one type of morphologically different leaves on the same plant ?
Heterophylly

In which country the hormone gibberellin was discovered ?
Japan

The edible part of turnip and carrot plants are nothing but roots. Which part of celery and rhubarb plants are consumed ?
Stem

Name the natural process involving loss of water from a plant in the form of liquid drops ?
Guttation

What is the colour of carotin ?
Yellow

What is the technical name of the natural opening in leaves meant for gaseous exchange ?
Stomata

Name the organell where photosynthesis takes place.
Chloroplast

What is the shape of chloroplast in spirogyra ?
Ribbon shaped

What is the other name for Nyctinasty movement ?
Sleep movement