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A shield is a protective device, meant to intercept attacks. The term often refers to a device that is held in the hand, as opposed to armour and a bullet proof vest.
The oldest form of shield was a protection used to block attacks by hand weapons and arrows. Shields have varied greatly in construction over time and place. Lightly armoured warriors relying on speed and surprise would generally carry small round shields sometimes made of metal but more often of wood.
The heavily armoured Roman legionaries carried large rectangular shields that could provide far more protection, but made swift movement more difficult. Famously the Romans used their shields to create tortoise like formations in which the entire group of fighters would be eclosed in an armoured box.
In the European Middle Ages diamond shaped shields, more easily used on horseback, became paramount. This inspired the shaped of the heraldic shield that is still used today.
Shields were used in war up until the 17th century, when gunpowder powered weapons made shields obsolete in the battlefield.
Shields for protection from armed attack is still used by many police forces around the world. Shields are sometimes used on artillery, as well.
Many non martial devices also employ shields. Space craft have heat shields to ensure and safe reentry. Electronics uses shielding to reduce electrical noise and crosstalk between signals. People and systems that must work in the presence of ionizing radiation are protected with shielding.
Science fictionScience fiction generally speaking, is a form of speculative fiction which deals principally with the impact of imagined science and/or technology upon society or individuals. There are, perhaps, exceptions to (or at least, some very unusual examples of) writers have imagined many futuristic shields, usually using force fieldIn general physics, a force field is a vector field representing the gradient of a potential. The vectors that are the values of a force field are forces, and so measured in units of force such as newtons and pounds. In the context of molecular dynamics,s. These include personal shields, as in the DuneDune is a science fiction novel by Frank Herbert. It was awarded the Nebula award in 1965 and tied for the Hugo award in 1966. It was also a huge commercial success and has now sold more than 20 million copies. Dune was followed by five sequels. The Dune series, or larger ones for spacecraft as in Star TrekStar Trek collectively refers to six science fiction television series, ten motion pictures, and hundreds of novels, video games, and other works of fiction all set within the same fictional universe created by Gene Roddenberry in the early to mid 1960s.. See shield (science fiction)Science fiction works such as Star Trek and Star Wars have popularized the concept of shields in the form of energy fields used to absorb hostile weapons fire. These shields are often featured on starships, although personal shields have also been describ for more.| Politics | Business | Finance |
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