COFFEE..all the facts

Legend of coffee 

Some archaeological evidence shows that humans were eating the coffee berries as long ago as a hundred thousand years.

One legend says that a goat herder in Ethiopia observed his charges eating the red berries from a nearby tree and became excited. Trying them himself, he too felt a great lift. By 600 AD that magical berry, and the brew made from drying and grinding its seeds, had found its way to what is now Yemen, on the southern tip of the Arabian peninsula.

Stories tell of a native of India smuggling the precious seeds of the tree out of Arabia around 1650 AD, then planting them in the hills of Chikmagalur. Arabian law forbad the exporting of beans that could germinate, effectively controlling coffee trade for centuries. Whether myth or history, the fruit of those seeds now forms a third of India's large coffee output.

Coffee facts 

- The first Espresso machine was introduced in 1822 by the French, but it was the Italians who perfected and distributed it.
-There is less caffeine in dark roast than in medium roast. It is because, the longer the beans are roasted, the more caffeine burns off.

- During the American Civil War, soldiers, having used up all their coffee supplies, used roasted sweet potato and Indian corn as a substitute.

-On the contrary to popular belief, coffee does not grow in plain brown beans. It actually grows in red berries, which normally carry two green beans each. Sometimes there's only one bean in the berry - this single bean is called a peaberry.The coffee berries are often called cherries.

-Cowboy coffee? well, yes, cowboys are said to have had one of the most peculiar ways of making coffee - they put ground coffee in a clean sock and put in a pot of cold water over a campfire.

- Ants don't like coffee, so you can use coffee to keep them away from you plants or out of your rooms. Just put the used coffee grounds around the plants or on the ant tracks in your house.

-When Admiral Josephus "Joe" Daniels became Chief of Naval Operations he forbid to serve alcohol on board ships. As a result, coffee became the drink of choice, thus the term "Cup of Joe".

-At first in Europe the coffee was known as Arabian Wine.
-When beans begin to cool after roasting, they release approximately 700 chemical substances which make up the vaporizing aromas.

-The most expensive coffee in the world is called Kopi Luwak. Kopi is the Indonesian word for the coffee and luwak is a local name of the Asian Palm Civet. Also known as Civet coffee it is made from coffee berries that have been eaten and passed through the digestive tract of the Asian Palm Civet (Paradoxurus hermaphroditus). The beans inside the berries pass through the system undigested and are then defecated. The beans are then washed and given only a light roast to avoid destroying the complex flavors that are developed through the process.

-The word "coffee" entered the English language in 1598 via Italian word caffé, which in return is derived from Turkish kahve that came into being via Arabic qahwa, a truncation of qahhwat al-bun meaning wine of the bean.
-The first coffee house was opened in 1471 in Istanbul and was called Kiva Han. The first European coffee house was opened in Italy in 1645.

-At first coffee was mostly grown in Ethiopia where it was cultivated by highlanders.

Caffeine molecule 

The perfect espresso requires 42 coffee beans.

Chemical Structure of Caffeine 

How much caffeine is in there? 

Amount of caffeine in one average cup (200 ml/7 oz):

Brewed coffee: 60-130 mg
Instant coffee: 65-100 mg
Decaf coffee: 2-5 mg
Black tea: 40-50 mg
Green tea: 15-25 mg
Hot chocolate: 3 - 35 mg

Shot of espresso (30ml/1oz) contains 25-30 mg caffeine

Red Bull Energy Drink (250 ml/8.3 oz): 80mg
Can of Cola (350 ml/12 oz): 35-45 mg

Dark chocolate: (100 g/3.3 oz) 66 mg
Milk chocolate: (100 g/3.3 oz) 20 mg

“Coffee is a beverage that puts one to sleep when not drank.
-Alphonse Allais”

Prepared by adding espresso into hot water. Strength is similar to drip coffee, but flavor is different0 points

Consists strong coffee (or espresso) with scalded milk.0 points

MARIE CURIE Physicist, Scientist Born in 1867 , died in 1934

Marie Curie was born Marya Salomee Sklodowska (sklaw DAWF skah) in Poland when that part of the country was under Russian rule. She was the youngest of five children. She had a brother and three older sisters.

When she was four years old one of her older sisters taught her the alphabet, and Manya (as they called her) learned how to read. In fact, she could read better than Bronya who had taught her.

Her father was a professor. Sometimes the family would rent out rooms to students to help pay the bills. At one time they had ten boys living in the apartment with the family, and Manya had to sleep on a couch in the dining room.

Her mother was very ill with tuberculosis* and died of the disease when Manya was ten years old.

When she graduated from high school she won a gold medal because she had been such a good student. Her father knew she had worked very hard, and as a reward, she was permitted to spend a whole year in the country with relatives. She enjoyed a marvelous year with her cousins.

She wanted to study when she returned to Warsaw, but there was no money to send her away to college. She and her sister did private tutoring to earn money. Manya told her sister she would work to send her to school, then when Bronya became a doctor, she could return the favor. That's what they did.

Marie became a governess to a family in the country and also had an opportunity to teach several peasant children to read and write.

She fell in love with her employer's son, but his parents thought she wasn't rich enough or good enough to marry their son.

Her sister invited her to come to Paris to live and begin her studies. Manya changed her name to a French name, Marie. At the Sorbonne, the university, she chose to study mathematics and physics. While studying there she lived in a cold apartment and survived on very little food, but when she graduated she had the highest grades in the class. She had a master's degree in physics. Then she was awarded a scholarhip and was able to study further to get a master's degree in mathemetics. She would also later receive a doctorate in physics.

She met Pierre Curie and they married in 1895. With the money a cousin gave her for a wedding present, Marie bought two bicycles, one for herself and one for Pierre. They pedaled through the French countryside on their honeymoon.

Marie and Pierre in the laboratory

Pierre and Marie began experimenting together and discovered two new radioactive elements. She named one of them polonium* to honor her native country Poland, and the other they named radium* . They worked four years preparing a very small quantity of radium in order to prove there really was such an element. They had to work with a ton of pitchblende* uranium ore to accomplish this. The Austrian government had provided the ore, and they only had to pay for transporting it. Marie worked hard carrying very large jars of liquid during those years of experimenting.

In 1903 Pierre and Marie along with Henri Becquerel (ahn REE beck REL) received the Nobel Prize* in physics for their work and their discovery of radioactivity* . The money they received made life a little easier, and they also used some of it to help friends and family members. In 1911 she was again awarded the Nobel Prize for discovery of the two new elements polonium and radium.

The Curies had two daughters, Irene and Eve. They were good, loving parents. Pierre was offered a professor's job at the Sorbonne. Life seemed to be getting easier for them.

Then the unthinkable happened; Pierre was killed when he stepped out in front of a wagon being pulled by horses. Marie was in shock. What would she do without him? She felt like only half a person with Pierre gone, but she was strong and able to continue their work. They let her start teaching his classes at the Sorbonne. She was the first woman to teach at the university. Pierre's father, Dr. Curie lived with the family and helped to raise the girls. Four years later, he too died.

During the First World War Marie determined she could best serve by outfitting some cars with x-ray machines which could be taken to the battlefield hospitals. Bullets and shrapnel* could be located with x-rays to help the doctors treat the wounded soldiers. Irene, who was seventeen years old, helped her mother by becoming a nurse and working with her on the battlefield. Marie trained 150 women to become x-ray technicians.

Madame Curie made two trips to America to receive a gram of radium each time, first from President Warren Harding and eight years later from President Herbert Hoover.

In 1923 the French government gave her a pension of 40,000 francs a year in recognition of her lifetime of work in France.

She became ill and died from all her years of exposure to radium. Today doctors identify the disease as leukemia.

After Marie's death her daughter Irene and her husband Frederic Joliot received the Nobel prize for their work in atomic research. She followed in her mother's footsteps to also become a great scientist.

Many people have benefited from the discoveries made by Pierre and Marie Curie. The radiation which burned their skin as they worked with it, eventually came to be used to kill cancer cells in patients suffering from the disease.

Nobel Gas NEON

Interesting facts about neon

The Noble Gas neon is one of the most inert elements known. Finding interesting facts about an element that does not do very much is difficult but I’ll try.

Starting with the elements basic properties, its atomic weight is 20.1797 and its density 0.0008999 grams per cubic centimeter. The ionization energy of neon is 21.565 eV and its oxidation state is 0.

Within the periodic table, neon occurs in period 2 and group 18. All group 18 elements have a complete outer shell of electrons. This configuration is very stable so they do not readily form compounds with other elements.

The scientists Sir William Ramsay and Morris M. Travers discovered the element in their studies on liquid air in 1898. During these studies, the pair also discovered two other noble gases - xenon and krypton. They named their newly found element after the Greek word “neos” meaning new.

Within the Earth’s atmosphere, neon occurs at a concentration of only 1 part in 65000. Despite this low concentration, commercial neon production is by the fractional distillation of liquid air. This process also produces the noble gases krypton, xenon and argon. Although rare in the Earth’s atmosphere neon is the fourth most abundant element in the universe. Naturally occurring neon consist of three stable isotopes neon-20, neon-21 and neon-22.

With a melting point of minus 248.59 C (24.56 K, minus 415.46 F) and a boiling point of minus 246.08 C (27.07 K, minus 410.94 F) liquid neon is of value as a liquid refrigerant. It has 40 times more refrigerating capacity than the more expensive liquid helium and more than 3 times that of the more explosive liquid hydrogen.

Within a discharge tube, neon exhibits a bright red glow. All the naturally occurring noble gases glow within discharge tubes but neon produces the brightest light at normal wattage and current. This ability has led to its major use in the world of advertising as it lights many an illuminated advertisement hoarding.

Of the compounds of neon very little can be said. It forms an unstable hydrate and possibly a compound with the highly reactive element fluorine.  An electrical discharge will cause neon to combine with mercury vapor. Van der Waal’s forces then hold this mercury-neon product together. Optical and mass spectroscopic analysis has revealed the presence of the following ions Ne+, (NeAr)+, (NeH)+ and (HeNe+).

Natural Mosquito Repellent Safety

It's easy to make your own natural mosquito repellent. You can control exactly what goes into the product so you won't need to worry about any unwanted chemicals.

Natural Mosquito Repellent Safety

There are a couple of different formulations you can make for your natural mosquito repellent. In general, what you are doing is diluting an essential oil that the mosquitoes find distasteful or which confuses them so they can't find you to bite you. The oils don't mix with water, so you'll need to add them to other oils or to alcohol. It's important to use an oil or alcohol that is safe for your skin. Also, don't go overboard with the essential oils. The oils are potent and could cause skin irritation or another reaction if you use too much. If you are pregnant or nursing, do not use any mosquito repellent, natural or otherwise, until after you've gotten it cleared by your physician.

Natural Mosquito Repellent Ingredients

If you are making large amounts of mosquito repellent, a good rule of thumb is to mix the repellent so it's 5-10% essential oil, so mix 1 part essential oil with 10-20 parts carrier oil or alcohol. For a smaller batch use:

• 10-25 drops (total) of essential oils
• 2 tablespoons of a carrier oil or alcohol

The essential oils that work well against mosquitoes are:

• cinnamon oil
• lemon eucalyptus oil
• citronella oil
• castor oil

Safe carrier oils and alcohols include:

• olive oil
• sunflower oil
• any other cooking oil
• witch hazel
• vodka

Natural Mosquito Repellent Recipe

Mix the essential oil with the carrier oil or alcohol. Rub or spray the natural insect repellent onto skin or clothing, using care to avoid the sensitive eye area. You'll need to re-apply the natural product after about an hour or after swimming or exercise. Unused natural insect repellent may be stored in a dark bottle, away from heat or sunlight.

Beautiful Gardens of the World.

Here’s the most beautiful parks in the world. As we know that one of the important element of a city is a park. Without any park, a city won’t get enough fresh air. So people in the world try to make a beautiful parks that also will server as a lung for the city. Here’s the most beautiful parks in the world that come from various countries, most of them located in United States.

Butchart Gardens, Victoria, British Columbia, Canada

Hundreds of Thousands of flowers bloom in various colors in this horticultural wonder. Flowers such as pansies, scillas, daphnes, and forsythis all lined up to form a magnificent scenery.

Butchart Gardens Victoria, British Columbia

Keukenhof, The Netherlands

Tulip is the national symbol of Holland and appeared in various Dutch history. Princess Maxima (with the help of the Russian president’s wife) led the opening of Keukenhof Garden. More than 7 million Tulips flower in 100 species is planted by hand every year on 80 hectares of garden area.

Keukenhof, the Netherlands

Golden Gate Park, San Francisco, United States

San Francisco is indeed a paradise for travelers. In Golden Gate Park, San Francisco many flowers from many different countries grown here. Like the Dutch tulip flowers, California native flowers, roses, Shakespeare flower, and even the original flowers of that area.

Royal Botanic Gardens, Kew, England

This flower garden used to be called with Kew flower garden and has an area of more than 300 hectares and a garden which has the largest plant collections in the world. In this garden, spring means the explosion of more than 5 million of the colorful light bulbs. The garden is more than 250 years old with tulips, daffodils, crocuses, irisis, snowdrops, and bluebells. Along with the arrival of spring, the visitors could see the flowers violas, pansies, nasturtiums and so forth.

The New York Botanical Garden, United States

The Bronx is a tropical paradise every spring in the orchid show event held every year.

Mirabell Palace, Salzburg, Austria

This garden is famous by the movie “The Sound of Music”. This park has the style of Baroque style from the era of the 17th century and has a row of purple flowers colored yellow, white, people, pink, and red. Do not be surprised if this garden inspire you to create a song.

Chanticleer, Wayne, Pennsylvania

This flower garden was once the private property of the offspring of Rosengarten, which means rose garden in Germany. This family gave this park so that It belongs to the public to be enjoyed every day. This flower garden has tulips, daffodils, and some flowering trees and vines, and several other flowers such as lilies, alium, and so on.

The Huntington Botanical Gardens, San Marino, California

This flower park located outside Los Angeles and has been modified from farmers workplace to be a heaven for flower lovers. This park is possessed more than 14,000 types of plants such as lily flower, and roses. Also do not miss the flowers from subtropical countries and Australia.

Grant Park, Chicago, Illinois, United States

Grant Park has always been a public property and the It’s for free. This is a gift because this park is located in the city center which is located between the busy district with Lake Michigan.

The Missouri Botanical Garden, St. Louis, Missouri, United States

First Built in 1859, an area of 79 hectares was spoiling their visitors with stunning scenery, beautiful flowers and colorful. This park have a Japanese nuance and attract a lot of people from foreign countries to visit.

The Dallas Arboretum, Dallas, Texas, United States

This park is still a young park Newly formed less than 30 years ago. The best place is in the Jonsson Color Garden, where tulips, daffodils, all waiting for you there.

. The Skagit Valley, Washington state, United States

This park is included in the list of “1000 places you should visit before you die”. Lot of tulips, daffodils, and so forth here.

The United States Botanic Garden, Washington, D.C.

When the congress planned in 1820 to make this park as a national park, it is a dream that come true. Today, the oldest national park located in United State’s capital is visited by 1 million people every year. This park is created from such various interested situations.

Suzhou Park, China

Suzhou garden has an oriental classic style as characteristics of China. The park built since the 11th century. Lingering Garden is the most famous part of the park, filled with bonsai plants, rocks, waters, and historic buildings.

Girl in the Suzhou Park, China

Honesty Pays.

 

The C.E.O. Story

A successful businessman was growing old and knew it was time to choose a successor to take over the business. Instead of choosing one of his Directors or his children, he decided to do something different. He called all the young executives in his company together. He said, "It is time for me to step down and choose the next C.E.O..I have decided to choose one of you."  The young executives were shocked, but the boss continued.

 

"I am going to give each one of you a SEED today - one very special SEED. I want you to plant the seed, water it, and come back here one year from today with what you have grown from the seed I have given you. I will then judge the plants that you bring, and the one I choose will be the next C.E.O.."

One man, named Jim, was there that day and he, like the others, received a seed. He went home and excitedly told his wife the story. She helped him get a pot, soil and compost and he planted the seed.  Everyday he would water it and watch to see if it had grown. After about three weeks, some of the other executives began to talk about their seeds and the plants that were beginning to grow.  Jim kept checking his seed but nothing ever grew. Three weeks, four weeks, five weeks went by, still nothing. By now others were talking about their plants, but Jim didn't have a plant and he felt like a failure.

Six months went by -- still nothing in Jim's pot. He just knew he had killed his seed. Everyone else had trees and tall plants, but he had nothing. Jim didn't say anything to his colleagues, however, he just kept watering and fertilizing the soil - he so wanted the seed to grow.  A year finally went by and all the young executives of the company brought their plants to the C.E.O. for inspection. Jim told his wife that he wasn't going to take an empty pot. But she asked him to be honest about what happened.

Jim felt sick to his stomach, it was going to be the most embarrassing moment of his life, but he knew his wife was right. He took his empty pot to the boardroom. When Jim arrived, he was amazed at the variety of plants grown by the other executives. They were beautiful -- in all shapes and sizes. Jim put his empty pot on the floor and many of his colleagues laughed, a few felt sorry for him!  When the C.E.O. arrived, he surveyed the room and greeted his young executives. Jim just tried o hide in the back.

"My, what great plants, trees, and flowers you have grown," said the C.E.O.. "Today one of you will be appointed the next C.E.O.!"

All of a sudden, the C.E.O. spotted Jim at the back of the room with his empty pot. He ordered the Financial Director to bring him to the front. Jim was terrified. He thought, "The C.E.O. knows I'm a failure! Maybe he will have me fired!"  When Jim got to the front, the C.E.O. asked him what had happened to his seed - Jim told him the story. The C.E.O. asked everyone to sit down except Jim. He looked at Jim, and then announced to the young executives, "Behold your next Chief Executive Officer! His name is Jim!" Jim couldn't believe it. Jim couldn't even grow his seed. "How could he be the new C.E.O.?" the others said.

 

Then the C.E.O. said, "One year ago today, I gave everyone in this room a seed. I told you to take the seed, plant it, water it, and bring it back to me today. But I gave you all boiled seeds; they were dead - it was not possible for them to grow.  All of you, except Jim, have brought me trees and plants and flowers. When you found that the seed would not grow, you substituted another seed for the one I gave you. Jim was the only one with the courage and honesty to bring me a pot with my seed in it. Therefore, he is the one who will be the new Chief Executive Officer!"

* If you plant honesty, you will reap trust

* If you plant goodness, you will reap friends

* If you plant humility, you will reap greatness

* If you plant perseverance, you will reap contentment

* If you plant consideration, you will reap perspective

* If you plant hard work, you will reap success

* If you plant forgiveness, you will reap reconciliation

So, be careful what you plant now; it will determine what you will reap later. "Whatever You Give To Life, Life Gives You Back"

Why do leaves change color in autumn

We all enjoy the colors of autumn leaves. The changing fall foliage never fails to suprise and delight us. Did you ever wonder how and why a fall leaf changes color? Why a maple leaf turns bright red? Where do the yellows and oranges come from? To answer those questions, we first have to understand what leaves are and what they do. Leaves are nature's food factories. Plants take water from the ground through their roots. They take a gas called carbon dioxide from the air. Plants use sunlight to turn water and carbon dioxide into oxygen and glucose. Oxygen is a gas in the air that we need to breathe. Glucose is a kind of sugar. Plants use glucose as food for energy and as a building block for growing. The way plants turn water and carbon dioxide into oxygen and sugar is called photosynthesis. That means "putting together with light." A chemical called chlorophyll helps make photosynthesis happen. Chlorophyll is what gives plants their green color. As summer ends and autumn comes, the days get shorter and shorter. This is how the trees "know" to begin getting ready for winter. During winter, there is not enough light or water for photosynthesis. The trees will rest, and live off the food they stored during the summer. They begin to shut down their food-making factories. The green chlorophyll disappears from the leaves. As the bright green fades away, we begin to see yellow and orange colors. Small amounts of these colors have been in the leaves all along. We just can't see them in the summer, because they are covered up by the green chlorophyll. The bright reds and purples we see in leaves are made mostly in the fall. In some trees, like maples, glucose is trapped in the leaves after photosynthesis stops. Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color. The brown color of trees like oaks is made from wastes left in the leaves. It is the combination of all these things that make the beautiful fall foliage colors we enjoy each year.

The Nobel Prize in Physiology or Medicine 1908

Ilya Ilyich Mechnikov

Paul Ehrlich

The Nobel Prize in Physiology or Medicine 1908 was awarded jointly to Ilya Ilyich Mechnikov and Paul Ehrlich "in recognition of their work on immunity"

Computers and How They Work

Computers and How They Work

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Why is it important to know how a computer works?  Easy, if you don't, it will be hard to control.  Computers were never built to control us even though that is how it appears.  Their creation was just another tool God gave man to use to benefit society.  What can you do to learn more about computers?  I have an easy answer.  Just read, and use computers more.  They are not that hard and with time you too can become the master over this tool. Computers, the ones we know and love have not been around all that long.  The first home personal computer was not sold until 1977.  We have come a long way since then.  Did you know that in 1983 there were approximately 2 million personal computers in use in the United States.  However just 10 years later in 1993 the number had jumped to more than 90 million.  And now in 2009 the number is estimated at over 200 million.
Computers, today are small, fast, reliable, and extremely useful.  Back in 1977 that really was not the case.  However, they both operated in basically the same way.  They both receive data, stored data, processed data, and then output data similar the the way our own brain functions.  This article deals with those 4 functions: Memory, Processing, Input, and Output.

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Memory Lets look at computer memory first.  The function of storage in a computer comes in many different sizes, types and shapes.  However there are two basic categories: short-term and long-term.  A typical computer contains numerous types of memory including RAM, ROM, virtual, cache, and various long-term storage devices.  Each type of computer memory serves a specific function and purpose. Computer memory is measured in bytes.  A single byte is made up of a series of 1's and 0's normally traveling in pairs of eight.  These eight 0's and 1's are the way the computer communicates and stores information.  With each keystroke or character a byte of memory is used.  In another article you will learn more about bits and how the computer thinks.
Measuring Memory

Term/Byte	Abbreviation	Value
Kilo	K, KB	1,024 bytes
Mega	M, MB, Meg	1,048,576 bytes (Million)
Giga	G, GB, Giga	1,073,741,824 bytes (Billion)
Tera	T, TB, Tera	1,099,511,628,000 bytes (Trillion)

Here is another way of looking at the measurement of memory:
Measuring Bytes

8 bits = 1 byte 1000 bytes = 1 kilobyte 1000 kilobytes = 1 megabyte 1000 megabytes = 1 gigabyte 1000 gigabytes = 1 terabyte

ROM
ROM, or read-only memory is permanent, long-term, nonvolatile memory.  Nonvolatile means is doesn't disappear when the computer is shut off.  It also can not be erased or changed in anyway.  However there are types of ROM called PROM that can be altered.  The P stands for programmable.  ROM's purpose is to store the basic input/output system (BIOS) that controls the start-up, or boot process.
RAM
RAM, or random-access memory unlike ROM works only when the computer is turned on.  This memory is vital to the computer because it controls the moment by moment processes of the computer.  The first thing that goes into RAM is the OS (operating system) which is most cases is Windows 95.  Next for the RAM might be a game, or the Internet browser, or some type of software that you want to use.
Early personal computer only needed about 64K of RAM.  Today that number is drastically higher.  With photos, sounds, and even movies going into RAM, the amount need is now in the millions.  The computer I am currently using has 80 MB or 80,000K of RAM.
Multitasking has put more demand on RAM in the past few years.  Multitasking is the ability to run more than one program at the same time.  For instance, many people like to run Netscape Communicator along with their word processing software.  This means you need lots of RAM to hold both programs.
Other types of temporary memory are cache (pronounced "cash") and virtual memory.  Both of these types of memory supplement the computer's primary RAM and perform the same function as RAM.

Storage Devices:

RAM and ROM may be very important parts of the computer; however, without storage devices like hard drives and disk drives your computer would not be near as useful.
Here are the most common forms of Storage Devices found on your home computer:
 

Thumb Drive or Memory Stick	Hard disk (drive) or HD
A device that in 1998 IBM introduced and has caught on very quickly as a great portable storage device.  It quickly replaced the floppy disk. This small device is extremely reliable and fits in the USB port on your computer.  It come in sizes ranging from 1 GB to 64 GB in size.	A stack of round metal platters called disks encased in a metal air tight shell.  They commonly range in sizes from 60  to 500 gigabytes (1000MB=1GB).  The hard drive's function is to store all the files, and software the computer will ever use.  Any file or software program used by RAM most likely will come from the disk drive.
CD-ROM (Compact disk, read-only memory)	DVD-ROM (digital video disk, read-only memory)
CD's function much like hard drive in that they store large amounts of memory.  What separates them is their mobility and optical storage technology.  Their storage capacity is also very limited compared to hard drives.  The can only hold up to approximately 650 MB of information.  The other big difference is that you have to have a special drive to write to CD's.  Otherwise they can only be read from.	DVD's are similar to CD in that they are written and read by laser.  Hard drives use magnetic currents store data.  However CD's and DVD's use light (laser) to write and read data on a disk.  These long and short pits are then stored or etched on the surface of the disk.  They can only be read by laser technology.  The new DVD technology increased the amount of memory a regular CD can hold.  DVD's can range in sizes from 4.34GB (1000MB=1GB)  to 7.95GB.

Processing If someone had to find the brains of the computer they would most certainly say its the microprocessor.  The microprocessor is often referred to as the CPU (Central processing unit).  The microprocessor is a chip the size of a postage stamp.  The processor is the one part of the computer that is most important to the computer.  The microprocessor controls how data is sorted and directs the flow of data. To a great extent a computer is defined by the power of its microprocessor.  Chips with higher processing speed and more recent design offer the greatest performance and access to new technologies.  Most microprocessors made for PCs are made by Intel or by companies that clone Intel chips, such as Advanced Micro Devices (AMD) and Cyrix.
The early Intel chip came in models called 286, 386, and 486.  The 586 chip was given the name Pentium.  The series of Pentiums were given the following names:  Pentium Pro, Pentium with MMX, and Pentium II.  The newer processors hold more transistors and thus more computing power on a single chip.
Microprocessor

Processor	No. of Transistors	Bus Width
80286	134,000	16 bit
80386	275,000	32 bit
80486	1,600,000	32 bit
Pentium	3,300,000	64 bit external/  32 bit internal
Pentium Pro	5,500,000	64 bit
Pentium w/ MMX	4,500,000	64 bit external/  32 bit internal
Pentium II	7,500,000	64 bit
The processor has come a long way and now some of the latest processors are: Celeron · Pentium Dual-Core · Core 2 · Core i5 · Core i7 · Xeon · Itanium  and who know what will come out next?

Input One of the best features of a computer is the ability to give the computer commands and feed it information.  Without an input device this would not be possible.  Input devices can be built into the computer, like the keyboard in a laptop, or it can be connected to the computer by a cable.  The most common input device is the keyboard.  There are lots of others such as: mice, trackballs, touch pads, touch screens, pens, joy sticks, scanners, bar code readers, video and digital cameras, and microphones.  In addition, storage devices such as disk drives can serve as input devices.

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Output Input is important but equally important is the ability to read what the computer is doing.  The computer output devices are used to serve the user.  The most common output device is the monitor, or screen.  However most computer come with speakers and a printer which are excellent output devices.  Storage devices such as disk drives and diskettes also serve as output devices when it is necessary to write new or updated data files to disk or tape.

Understanding pulleys

Understanding the Block and Tackle
Imagine that you have the arrangement of a 100 pound (45.4 kilogram) weight suspended from a rope, as shown below:

In the above figure, if you are going to suspend the weight in the air then you have to apply an upward force of 100 pounds to the rope. If the rope is 100 feet (30.5 meters) long and you want to lift the weight up 100 feet, you have to pull in 100 feet of rope to do it. This is simple and obvious.

Now imagine that you add a pulley to the mix, as shown below:

Does this change anything? Not really. The only thing that changes is the direction of the force you have to apply to lift the weight. You still have to apply 100 pounds of force to keep the weight suspended, and you still have to reel in 100 feet of rope in order to lift the weight 100 feet.

The following figure shows the arrangement after adding a second pulley:

­This arrangement actually does change things in an important way. You can see that the weight is now suspended by two pulleys rather than one. That means the weight is split equally between the two pulleys, so each one holds only half the weight, or 50 pounds (22.7 kilograms). That means that if you want to hold the weight suspended in the air, you only have to apply 50 pounds of force (the ceiling exerts the other 50 pounds of force on the other end of the rope). If you want to lift the weight 100 feet higher, then you have to reel in twice as much rope 0- 200 feet of rope must be pulled in. This demonstrates a force-distance tradeoff. The force has been cut in half but the distance the rope must be pulled has doubled.

The following diagram adds a third and fourth pulley to the arrangement:

In this diagram, the pulley attached to the weight actually consists of two separate pulleys on the same shaft, as shown on the right. This arrangement cuts the force in half and doubles the distance again. To hold the weight in the air you must apply only 25 pounds of force, but to lift the weight 100 feet higher in the air you must now reel in 400 feet of rope.
A block and tackle can contain as many pulleys as you like, although at some point the amount of friction in the pulley sha­fts begins to become a significant source of resistance.

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