Elementary financial records are known from the beginning of history. Baked clay records were done before the invention of writing.
In the 17th century, merchants started storing their gold with goldsmiths in London. The goldsmiths had their own vaults, and charged a fee for storing the merchants' gold. The goldsmiths eventually started loaning money using the gold left to them, and also paid interest on the gold.
The Bank of England began issuing banknotes in 1695. The oldest bank still in existence is Monte dei Paschi di Siena in Siena, Italy, which started in 1472.
A bank usually provides the following services:
Halley's Comet
Halley's Comet (Comet Halley) is a comet which comes round every 75 or 76 years. When it is near, it can be seen with the naked eye. It will return in 2061.
The comet is named after Edmond Halley (1656–1742), an English astronomer, who predicted the comet's return. Halley's Comet was the first comet to be recognized as periodic. (Periodic means that it comes by Earth regularly.)
When the comet came close to the Earth in 1986, it was visited by several space-probes. The probe "Giotto" from the European Space Agency managed the closest approach to the comet.
The number of years that the comet finishes its full cycle can vary depending on the effect of another planet's gravitational pull.
In 1986, Halley's Comet was the first to be observed in detail by spacecraft. It gave the first data on the structure of a comet nucleus and how the "coma" (nebulous envelope around the core or nucleus) and the tail formed. These observations supported Fred Whipple's "dirty snowball" model. This correctly predicted that Halley would be composed of a mixture of volatile ices – such as water, carbon dioxide, ammonia, – and dust. The missions also adjusted these ideas. For example, it is now known that the "surface" of Halley is mostly dusty, non-volatile materials, and that only a small portion of it is icy.
Hubble Space Telescope
The Hubble Space Telescope (HST) is the first big optical space observatory telescope. Being above the atmosphere means it can see the sky more clearly than a telescope on the ground. The atmosphere blurs starlight before it reaches Earth. Named after the astronomer Edwin Hubble, the Hubble Space Telescope can observe 24 hours a day. The main mirror is 94.5 inches (2.4 meters) across. The telescope can take pictures of things so far away it would be nearly impossible to see them from anywhere else.
It was made by both NASA and the ESA working together. It is 600 km in space and was launched on April 24, 1990. Like other things in low Earth orbit it travels at 5 miles (10 km) per second. If you were going this speed on Earth, you would be able to get from New York to San Francisco in 10 minutes. This speed creates difficulty in scheduling observations.
The Hubble itself is the size of a large school bus, but still small enough to fit inside the cargo bay of a Space Shuttle. It was repaired in 1993 due to problems in the picture quality.
The telescope was launched in 1990 by a space shuttle. When it entered orbit, everything seemed fine. But there was a problem with the telescope that was not discovered until it started taking pictures.
When the HST took its first pictures, astronomers were happy to see the images, but they were not as sharp and as crisp as expected. Telescopes in space can take better pictures than telescopes on Earth, but for some reason, the pictures were not better than the pictures taken on Earth. They found a problem with the telescope's mirror. The mirror was not curved right. It was only wrong by 2.2 microns (1/50th as thick as a piece of paper). Still, this was enough to cause the images to be blurred. Some said that Hubble was nearsighted.
Another space shuttle was soon sent up to repair the space telescope. The repair was not easy. The astronauts had to install some small mirrors to correct the light from the big mirror. The big mirror could still be used. It took five days of space walks. When an astronaut opened one of the doors on Hubble to install a new camera, the door would not close. The astronauts had to think of a creative way to get around the problem. Eventually, Hubble was fixed.
Repairs and servicing missions have been made to the Hubble Space Telescope five times to keep it in orbit and make it even better as technology improved. The space shuttle program was kept going longer than planned to send an extra trip up to the Hubble Space Telescope for a final fix.
Hubble will be replaced by the James Webb Space Telescope which will be located even further from Earth. There are now other telescopes in orbit, like the Herschel Space Observatory and the Kepler Spacecraft, which was specially made for finding Earth-like planets around other stars.
Motion sensor
A motion sensor is a sensor device. It is used for studying motions. It is connected to a . The data-logger is connected to a computer. The computer runs a data-logging program. The computer is connected to power, and a security system. Motion sensors have many uses including security.
Applications for movement sensor technology include clinical, workplace safety & athletic sports.
Arm
An arm is a limb. Most humans have two arms each, coming out of their body at the shoulder, just below the neck. On the end of each arm is a hand. Humans use arms and hands to do things to other objects, this is called manipulation. The main purpose of the hand is to grasp objects. Some other primates have arms which they use to move around by holding onto trees or supporting themselves as they walk along the ground. Fingers and hand, wrist, forearm, elbow, upper arm and shoulder are parts of the arm.
Arrow
An arrow is a projectile fired with a bow. A bow and arrow is a weapon used before medieval times and later. For thousands of years, people all over the world have used bows and arrows for hunting and for defense. Arrows have a sharp point at one end and usually a flight at the other end. The flight is usually made of feathers and helps the arrow go through the air straight. Someone who makes arrows is a fletcher.
A picture of an arrow is often used to point to something. Arrows look may like this: -->. "Double-headed" arrows look like this: <-->.
Golf
Golf is a game played in an open field where the golfer plays his golf ball into a hole by using different types of clubs (golf instruments). The book "Rules of Golf" reads "The Game of Golf consists in playing a ball from the teeing ground into the hole by a stroke or successive strokes in accordance with the Rules."
In golf, a golfer plays a number of holes in a given order. 18 holes played in an order controlled by the golf course design, normally make up a game. On a nine-hole course, two nine-hole rounds make up a normal game.
Each hole starts from the teeing area. Golfers put the ball on a small stand called a tee and swing a club at it to try and hit it as straight and far as possible. Once each golfer in the group has done this, the person whose ball landed farthest from the hole hits his again, followed by everyone else, one person at a time, until everyone is on the green. The green is the area near the hole where the grass is cut very short.
Once on the green the players will try to "putt" the ball into the hole. Putting is similar to a regular swing except it is not as hard and the player does not want the ball to go in the air. Once each player has put their ball into the hole, the group moves on to the next hole.
Each time a player swings at his ball, it is considered a "stroke". Each hole is a certain number of strokes that golfers are expected to need to get their ball into the hole. This is known as the "par". If a player gets his ball in the hole in less than the par he gets a "birdie". If it takes him one more shot then the par it is known as a bogey. Most holes have a par between 3 and 5.