2 p.m., at a convenient store.
Black and white bars, barcode.
“Gong-sang, please get me one!”
“O..okay, take your pick.”
Gong-sang drops by a convenient store with his friends to keep his word that he would buy sodas for them on the way home. He wants to say ‘No’ to the other girls who started nagging him for one too, but he doesn’t to keep his popularity.
“Beep, beep, beep, beep!”
Whenever the cashier puts a hairdryer-like device over the soda can barcodes, it makes a beeping sound and the register shows the price. Gong-sang is surprised by the total amount.
“Duh!5,600 KRW? Something’s wrong. There are seven of us, but why are there eight sodas?”
“How should I know? If there is a mistake, you can pay for only seven.”
As soon as the cashier takes out one of the eight cans, Mal-sook shouts.
“Oh, no!”
It turned out that she secretly put in the eighth can. Her crazy shouting causes a small uproar in the store.
<Let’s get things straight! Nobinson’s special lecture>
Mal-sook: Oooh, my coke! I want to be in a world without barcodes!
Wang Soo-jae: Barcodes didn’t do anything wrong. And no matter how you try, you can’t live without them Every single product from a factory has its own barcode, not to mention this and all Nobinson’s books.
Mal-sook: Where is it on this book? I don’t see it.
Huh Gong-sang: Check the bottom on the back cover. Do you see black and white bars with different thickness? That’s a barcode. Each bar includes information such as the price, the country of origin, the publisher’s name, the area and title of the book, etc.
Wang Soo-jae: ‘Barcode’ is a compound word of ‘bar’ and ‘code.’ Since the product information is encoded in the barcode, it cannot be read as it is; we need a reader to read it. Do you remember at the store? A device that looks like a hair dryer is the reader.
Nobinson: You know, I am learning Chinese songs these days. They all sound like codes, so I used an electronic translator to put Chinese lyrics into our language. Let’s say that Chinese is a barcode and the translator is a reader.
Mal-sook: Captain Nobinson is such a teacher! I guess Soo-jae is like a code within a barcode, and captain is the reader.
Wang Soo-jae: Yah, what a lovey-dovey couple. Anyway, a laser beam comes from the reader before a barcode is read. The black bars absorb and the white bars reflect the beam with different levels according to the size of the bars. The reflected light is converted into electrical signals so that the product name is shown.
Sim Su-ri: By the way, how is the price determined?
Huh Gong-sang: The barcode reader is connected to the computer at the register. So, the electrical signals are sent to the computer, and then it reads the embedded information to show the product name and price on the monitor.
Nobinson: The numbers under the barcode are kind of agreed codes – as if in military, soldiers say ‘sweet potato’ as their own code to identify themselves as our side. The numbers are embedded in the bars.
Mal-sook: Oh I see! That’s why they type in the numbers when the reader won’t read the barcode.
Nobinson: At this point, aren’t you curious what the numbers behind this book mean? I have prepared this for you, take a good look at this.
Image description
Book number 978: this number represents that the product is a book.
Country code 89: this number represents National Library of Korea, which means the book is made in Korea.
Publisher code 92130: this number represents DDStone Publishing Company.
Publisher’s book code 49: this number represents this book, Nobinson Quiz Special Force.
Security number 3: this number is for checking if the barcode is correct.
In Mal-sook’s speech bubble: the space at the front and the back of a barcode indicate the start and the end of the information.
<Did you know? Special force’s secret notes>
What do you think is the fastest and the furthest traveler in the world? It is light. And the properties of light enable us to send signals, which means transmitting information by means of specific signs. For example, traffic lights that lead cars and pedestrians using colors, vehicles’ turn signals, landing strip lights for airplanes, barcode readers with a laser beam, optical communications, and others are depending on this principle.
Optical communication is communication at a distance using light to carry signals. High-speed internet at home and offices use optical communication. Using the form of light, it can send lots of signals quickly and simultaneously.
Scientists have been developing quantum computers that store information using light which is much faster than electrical signals. With this computer, we can finish calculating that which would take a thousand years with current technology, in a matter of a few minutes.
What is a laser beam?
A laser beam might remind you of the lightsaber in Star Wars or the laser beam coming out of the eyes of X-Men. These laser beams in sci-fi movies are light made by putting gas, liquid or solid substances into laser devices. The device emits light when atoms go from an excited state (by absorbing energy) to a ground state. These continuing reactions of absorbing and releasing energy by atoms are the laser beams.
As a laser beam generates light with one kind of substance in reaction, it has only one color in contrast with the sunlight that is a mixture of different colors. Also, since it is very thin and doesn’t spread out, laser light can be focused to a very small point of light. Thus, lasers are used in industry to accurately cut thick steel plates or diamonds. Besides, they are used in storing or reading information on CDs, reading barcodes, performing precision eye or skin surgery and performing fantastic shows.
Up-and-coming successor to barcodes, electronic tags.
There are more and more markets using electronic tags on their items. With electronic tags on, the price of items in a shopping cart can be calculated and the store staff do notneed to count inventory in stock.
Electronic tags use wireless communication technology. A semiconductor chip including product information is inserted in the product, and then the tag exchanges information between a tagged object and a reader. In other words, product information is obtained without direct contact. Various information such as the product name, price, expiration date, production region, cooking recipe and so on can be stored on an electronic tag. Moreover, it is recyclable. This is why it is considered a magical tag that would eventually replace barcodes.
2.30 p.m., on the way home.
“Ahh, it is so refreshing!”
Taking a sip of coke, Gong-sang’s body shivers at the sharp sensation from the carbonated soda. Poor Mal-sook only takes a gulp looking at him.
“Hey, Gong-sang, can I have a sip? I won’t drink directly from the can.”
Losing her patience, Mal-sook asks him to let her try at least a sip of his coke.
“Huh? What is it?”
Mal-sook catches Sim Su-ri taking something out of his pocket making a rustling sound. It is a can of coke he lifted from the store. Mal-sook snatches the can from his hand, but he takes it back from her. She then proceeds to take it back again.
“Agent Sim Su-ri! I can’t believe you did that. I am warning you. Give me that.”
Mal-sook and Sim Su-ri stop fighting when Captain Nobinson solemnly scolds him. There is no doubt that the truthful captain would take it back to the store. Surprisingly, however, he snaps the lid… and bang! The soda bursts into foam, showering the captain’s face. While Sim Su-ri and Mal-sook were fighting over the can, soda bubbles had built up pressure inside.
<Let’s get things straight! Nobinson’s special lecture>
Mal-sook: Ha! It served you right! You tried to drink it by yourself! Ahhhh. you, no, captain spilled the precious coke!
Nobinson: Hey, that’s unfair! I was trying to share it with you. Right at this moment when nobody understands me I do need to have refreshing cold coke… Is there no coke left?
Wang Soo-jae: Flat coke doesn’t have the refreshing taste, because it doesn’t contain carbon dioxide gas that makes it refreshing.
Nobinson: That’s why drinks like coke and lemonade are called carbonated drinks, or soft drinks because of their fresh flavor.
Huh Gong-Sang: By the way, how can gases dissolve in water?
Wang Soo-jae: By increasing the pressure. Coke and lemonade are made by dissolving carbon dioxide into the syrup and flavoring-mixed water in an environment triple or quadruple the atmospheric pressure. The higher the pressure, the more gas, like carbon dioxide, can be dissolved into water since more particles are colliding.
Nobinson: Oh, poor carbon dioxides! How stuffy they would feel in the pressurized water. No wonder they run away right after the cap is opened.
Sim Su-ri: Now that explains why a coke with its cap opened for a while tastes flat.
Mal-sook: Okay, guys! I will tell you my special secret to feel the sharp sensation that even stings your nose: drink a coke after refrigerating it until it gets really cold.
Wang Soo-jae: What kind of secret method is that? It is common sense. The lower the temperature, the less gas gets activated and stays in the liquid longer. This is why carbonated drinks are made in a temperature below -40 degrees Celsius so that carbon dioxide can dissolve easily.
Huh Gong-sang: I have seen that my dad’s favorite drink, beer, foams up. Then beer is also made of dissolved carbon dioxide like coke?
Nobinson: Ahh, cold beer… Oops! What am I talking about? Hmm anyway, I kind of have an intimate knowledge of alcohol. Beer is a different case. It is made by dissolving carbon dioxide produced from naturally fermented starch with high pressure.
Wang Soo-jae: Anyway, what a pity that you wouldn’t be able to have soft drinks at school orthe library anymore.
Mal-sook: What? What on earth are you talking about?
Wang Soo-jae: Too many soft drinks cause obesity, weak bones and cavities, because they disrupt absorption of calcium and they are acidic. So not only cafeterias but also vending machines at schools and libraries are prohibited from selling fizzy drinks.
Mal-sook: Oh, no! no! But I still love soft drinks.
<Did you know? Special force’s secret notes>
Just a glass of soft drink doesn’t make bubbles cling to the inside of the glass. However, when a straw, buttons or raisins are put in, carbon dioxide gas sticks to their surface. This is because the gas dissolved into a soda turns into air bubble easily when it meets small substances. In this way, you can make a bomb that explodes like a volcano by putting mint candy or Mentos in a carbonated drink; Gum Arabic, an ingredient of Mentos or mint candy, immediately react with the carbonate dissolved in the soda and produce carbon dioxide. And the roughness of candies provide more crannies that allow new bubbles to form more quickly and explode. So, you don’t want to eat mint candies or Mentos with soft drinks, right? Do not try it as the bubbling gas inside your body might cause upset stomach or intestine.
Hidden secrets of canning carbonated drink.
Can materials: Since carbonated drinks are acidic, cans for them shouldn’t be made from iron - they will be corroded and end up spoiling the contents. This is why aluminum is ideal for holding carbonated beverages: it is light-weight, noncorrosive and recyclable.
Cylindrical shape: A circle has the shortest circumference compared toother shapes with the same area, and the smallest area compared to those with the same volume. If we consider a sphere, it will not stay in one place. So a cylindrical shape is the most practical and economical answer.
A seam: Aluminum cans are seamless. Using the extensible property of aluminum, it is cut into a round shape, put into a mold and stretched to become a cylindrical shape.
Concave bottom: The pressure inside the can is very high and will expand even with a slight increase of temperature. If the bottom of aluminum cans were made flat instead, they would tend to bulge outward from the pressure, thus making the bottom protrude. If it is concave, the can pushes on the dome, putting pressure on the other parts of the can, thus making it stronger.
You can dissolve an eggshell with soft drinks.
What you will need: A boiled egg, coke or lemonade and a glass with a wide mouth.
Perform the experiment: Fill the glass 2/3 full with coke or lemonade. And then put the egg in the glass.
The secret of soft drink dissolving eggshells.
An eggshell contains calcium carbonate. It reacts with acid to form carbon dioxide. So if you put an egg in soft drink, you can see carbon dioxide bubbles formed on the eggshell. Carbonic acid has similar level of acidity as vinegar. When you consume too much soft drink the bacteria that live in your mouth create acids which lead to cavities in your teeth. Because a tooth consists of substances that are easily dissolved by acid like eggshells.
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