Contact lens

A contact lens (also known as a "contact") is a corrective, cosmetic, or sometimes protective lens located on the cornea of the eye.
Contact lenses are obtainable in a number of varieties, including hard and soft. Hard contacts are classically not disposable, while soft contacts often are. Some soft contacts are also well-known as extended wear lenses. Contact lenses (both soft and hard) are made a variety of types of polymers, the latest containing some variant of silicone hydrogel. Previously, hard contact lenses were made of a polymer known as PMMA. They have since been replaced by rigid gas-permeable (RGP) contact lenses. Many contact lenses are made of hydrophilic (water-absorbing) materials, thereby allowing oxygen to reach the cornea, and make the lens more comfortable to wear.
Heavily tinted contacts are tinted to change the color of the iris, and are used for cosmetic reasons. Some standard contact lenses are somewhat tinted in order to make them more visible for handling purposes.

Clock

A clock is an instrument for measuring time.Those used for technical purposes, of extremely high accuracy, are sometimes called chronometers. A portable clock is called a watch. The clock in its most common modern form displays the hours, minutes, and sometimes seconds that pass over a twelve or twenty-four-hour period.
The world's first self-striking clock was said to be invented by Chang Yeong-Sil, a chief enginner of Korea, in Korea during the Joseon Dynasty. It was called Chagyongru, which means "self-striking clock" in Korean
The development of electronics in the twentieth century led to clocks with no clockwork parts at all. Time in these cases is measured in several ways, such as by the behaviour of quartz crystals, or the decay of radioactive elements. Even mechanical clocks contain since come to be largely powered by batteries, removing the need for winding.

Spacecraft propulsion

Spacecraft propulsion is used to modify the velocity of spacecraft and artificial satellites, or in short, to provide delta-v. There are many dissimilar methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. Most spacecraft today are propelled by heating the reaction mass and allowing it to flow out the back of the vehicle. This sort of engine is called a rocket engine.
All current spacecraft use chemical rocket engines for launch, though some have used air-breathing engines on their first stage. Most satellites have simple reliable chemical rockets (often monopropellant rockets) or resistojet rockets to keep their station, although some use momentum wheels for attitude control. Newer geo-orbiting spacecraft are initial to use electric propulsion for north-south stationkeeping. Interplanetary vehicles mostly use chemical rockets as well, though a few have experimentally used ion thrusters with some success

American White Pelican

The American White Pelican (Pelecanus erythrorhynchos) is a very large (50"–70") white bird with black wing tips and an huge orange bill. They have a wing span of approximately 3 m . They are elegant in flight, moving their wings in slow powerful strokes.
Unlike the Brown Pelican, the American White Pelican does not dive for its food. Instead it practices helpful fishing. Each bird eats more than 4 pounds of fish a day, mostly carp, chubs, shiners, perch, catfish, and jackfish.
White Pelicans nest in colonies of a number of hundred pairs on islands in remote brackish and freshwater lakes of inland North America. The female lays 2 or 3 eggs in a shallow depression on the ground. Both parents incubate.
An American White Pelican at Edinburgh Zoo.
Visible on the bill are the remains of a protrusion grown throughout breeding season.They winter in central California and along the Pacific coast of Guatemala; also along the shores of the Gulf of Mexico.
Shooting by poachers is the main known cause of mortality. Colonies are responsive to disturbance and visits by humans can cause the pelicans to leave and abandon their nests.
This species is protected by the Migratory Bird Treaty of 1972.
The scientific name for this species combines Pelecanus, the Latin for pelican, with erythrorhynchos, derived from the Greek words erythros meaning red, and rhynchos meaning beak.

Spider silk

Spider silk is a fibre secreted by spiders. Spider silk is a remarkably physically powerful material. Its tensile strength is similar to that of high-grade steel — according to Nature , spider silk has a tensile strength of approximately 1.3 GPa, while one source lists a tensile strength for one form of steel at 1.65 GPa. However, spider silk is much less dense than steel; its ratio of tensile strength to density is perhaps 5 times better than steel — as strong as Aramid filaments, such as Twaron or Kevlar. In fact, a strand of spider silk long sufficient to circle the earth would weigh less than 16 ounces (less than 460 grams).
Spiders usually use their silk to make structures, either for protection for their offspring, or for predation on other creatures. They can also suspend themselves using their silk, in general for the same reasons.
The Trapdoor spider will burrow into the ground and weave a trapdoor-like structure with spindles around so it can tell when prey arrives and take it by surprise.
Many small spiders use silk threads for ballooning. They extrude several threads into the air and let themselves become carried away with upward winds. Although most rides will end a few meters later, it seems to be a ordinary way for spiders to invade islands. Many sailors have reported that spiders have been caught in their ship's sails, even when far from land.

Kite fishing

Kite fishing is supposed to have been first invented in China. It was, and is, also used by the people of New Guinea and other Pacific Islands - either by cultural distribution from China or independent invention.
Kites can give the boatless fishermen access to waters that would otherwise be available only to boats. Similarly, for boat owners, kites provide a way to fish in areas where it is not safe to find the way such as shallows or coral reefs where fish may be plentiful. Kites can also be used for trolling a lure through the water.
Suitable kites may be of very easy construction. Those of Tobi Island are a large leaf stiffened by the ribs of the fronds of the coconut palm. The fishing line may be made from coconut fibre and the lure made from spiders webs.
Modern kitefishing is popular in New Zealand, where large delta kites of synthetic materials are used to fish from beaches, taking a line and hooks far out past the breakers. Kite fishing is also emerging in Melbourne where sled kites are becoming well-liked, both off beaches and off boats and in freshwater areas. link title The disabled community are ever more using the kites for fishing as they allow mobility impaired people to cast the bait further out than they would otherwise be able to.

Giant panda

The giant panda (Ailuropoda melanoleuca) ("black-and-white cat-foot") is a mammal classified in the bear family, Ursidae, native to central and southern China.It is easily known by its large, distinctive black patches around the eyes, ears and on its rotund body. Though technically a carnivore, the panda has a diet which is 98% bamboo. However, they may eat other foods such as honey, eggs, fish, and yams.
The Giant Panda is an endangered animal; an estimated 3,000 pandas live in the wildand some 221 were reported to live in captivity at the end of 2006 in China,with twenty pandas living outside of China. However, reports show that the numbers of wild panda are on the rise.The giant panda has long been a most wanted of the public, at least partly on account of the fact that the species has an appealing baby-like cuteness that makes it seem to resemble a living teddy bear. The fact that it is regularly depicted reclining peacefully eating bamboo, as opposed to hunting, also adds to its image of innocence. Though the giant panda is often assumed docile because of their cuteness, they have been known to attack humans, usually assumed to be out of irritation rather than predatory behavior.