​​Can a country actually claim the Moon or other celestial body as their territory?

The Outer Space Treaty
''Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies''
The treaty is the foundation of international space law for signatory nations (108 in 2019). The treaty presents principles for space exploration and operation:
-Space activities are for the benefit of all nations, and any country is free to explore orbit and beyond.
-There is no claim for sovereignty in space; no nation can “own” space, the Moon or any other body.
-Weapons of mass destruction are forbidden in orbit and beyond, and the Moon, the planets, and other celestial bodies can only be used for peaceful purposes.
-Any astronaut from any nation is an “envoy of mankind,” and signatory states must provide all possible help to astronauts when needed, including emergency landing in a foreign country or at sea.
-Signatory states are each responsible for their space activities, including private commercial endeavors, and must provide authorization and continuing supervision.
-Nations are responsible for damage caused by their space objects and must avoid contaminating space and celestial bodies.

​​Why do some Powerlifters sniff Ammonia Powder?

Whether or not you have heard of ammonia before, you are in contact with it on a daily basis. In fact, you have ammonia inside of you right now. Scientifically known as ammonium carbonate, ammonia is a colorless and smelly gas at room temperature. It is one of the most common industrial chemicals used today, and you can find it in everything from cleaning products to fertilizer.
Not only can you find it in many of your household products, but you can also find it inside of your own body! Your body produces ammonia by itself and uses it for a number of different bodily reactions, including working as a precursor for amino acids. Additionally, ammonia exists naturally in the environment and is an integral part of almost every ecosystem on earth.
Powerlifters, heavy weightlifters, and even professional football players are well known for sniffing ammonia. The specific type of ammonia that they sniff is a powder version that we have come to call smelling salts.
The ammonia gas gets turned into a powder form and then gets put into capsules. Smelling salt capsules are widely available.  These days, you can find the exact same capsules that athletes use at your local drugstore.
First off, the ultimate reason why most athletes sniff smelling salts is to boost their athletic performance and maximize their abilities.  In the case of powerlifters, that means being able to lift the heaviest weights when it matters the most. 
For other athletes, like football players, it could mean making the ultimate tackle or running your absolute fastest. 
Second, powerlifters and athletes sniff smelling salts to help reduce body aches and pains.  Specifically, they use it to reduce muscle soreness.  Alleviating soreness indirectly enables them to lift heavier weights and improve their athletic performance even more. 

​​What is the science behind Frying Food in oil?

Frying occurs when a food is introduced to hot oil and rapidly begins to dehydrate. When the food is submerged in the oil, the water within the ingredient immediately starts to boil and rise to the surface, causing free fatty acids to form. A starchy crust around the outside helps to lock in moisture, preventing the food from becoming completely dehydrated.
During the frying process the Maillard reaction occurs, resulting in a golden brown color and rich flavor. The heat from the oil also cooks the interior of the food, allowing the fibers to soften, proteins to denature, and starches to gelatinize.
The protective crust around the food is typically formed with starch-heavy foods, such as breadcrumbs or flour-based batters, although naturally starchy foods like potatoes can create their own crunchy outer layer while in the fryer. This barrier is essential to the frying process in order to lock in the moisture and avoid excess oil absorption.

​​How do Engineers demolish a Skyscraper?

The word demolition means destruction, breaking down or removal. Demolition of building is the process of dismantling or destroying of a structure after its life of serviceability by pre-planned and controlled methods.
Different steps are involved in the process of demolition of building structures which are:
•Surveying
•Removal of hazardous materials
•Preparation of plan
•Safety measures
There are two types of demolition methods used for buildings and structures:
•Non-explosive demolition
•Explosive demolition

Non-explosive demolition:
It means the demolition of a structure done with some equipment without the use of any explosive. Different equipment’s used for the demolition activity are Excavators and Bulldozers,
Wrecking Balls etc

Explosive demolition:
Implosion Method of Building Demolition, Implosion is the process of demolition of a building using explosives. If the supports of the building are removed, the structure collapses.
Using implosion technique, the main supports of the buildings such as column’s, beams and slab are fixed with explosives. When these explosives are detonated, the column collapse and so is the structure.
Depending how the structure falls, there are two types of implosion:
Falling like a tree: In this type of implosion, the building is made to fall like a tree to the sideward. This is the commonly used type of implosion. When free space is available besides the building, this type of demolition is prescribed.
Falling into its own footprint:
When the free spaces are not available around the building and the structure around the building are to be protected. This type of demolition is used. In this type of demolition, explosives are set in the floor below the middle part of the building.
As the explosions are detonated, the upper part of building destroys and falls upon the lower building. Due to the heavy load and force the lower part of the building also collapses and falls on its own footprint.

​​Why do Airlines dim the cabin lights during Take-off and Landing?

There are a couple of reasons behind this and some other things airlines insist upon at the time of landing - lifting up the shades, putting the seat upright and turning off the overhead lights.
• The possibility of the wings catching fire is highest during take off and landing. We, the passengers, play an important role here. The pilots rely on us to be their eyes and ears and report any instance of fire - after all, the passenger sees it first! The lights are dimmed inside the aircraft to make the detection easier.
• There is of course the adjustment of the eyes to the bright light outside in case of being an emergency landing factor that other answers have described in detail.
• The shades need to be up in order to assess the state of the aircraft. The passengers would be visible from outside and if a hijack is suspected, the rescue mission needs to be able to see the activities within.
• Shades need to be up at the time of take off so that in case an aircraft strays into restricted air territory, air checks can look into the aircraft.
• The seats are in an upright position so that precious time is not wasted in evacuation in case of emergency.
These airline rules have evolved over time and are implemented almost everywhere.

​​What is the meaning of Rx, Nrx and XRx printed on medicine packs?

This is related to pharmacology and pharmacy.
Generally, in a prescriptions written by doctors have these symbols at the beginning.
• Rx-
◦ It actually comes from the word ‘Recipere’, meaning prepare.
◦ In medieval times, pharmacists used to make drugs and doctors would just write down the components and amounts to be needed and send the patients to the pharmacists with the prescription. The pharmacist would then prepare the drug as per doctor’s instruction and give it to the patient with proper drug regimen.
◦ Now, pharamcists do not prepare drugs, rather dispense them. So Rx signifies the drugs in schedule H & H1 non-narcotic drugs, that means the can only be obtained by producing a prescription and not over-the-counter.
• NRx-
◦ The extra N prefix means the drug in the prescription has narcotic properties and are addictive.
◦ This also means that the prescription needs to be filled and signed every time by a doctor and the drug cannot be obtained if the prescription doesn't contain a recent date.
• XRx-
◦ This means the prescription contains a Narcotic and Psychotropic drug.
◦ So the drug retailer has to save a copy of the prescription for 2 years and has to produce the them on any enquiry on court order.
Nowadays these are not commonly used. Doctors usually write ‘Adv’ means ‘Advice’ and then write the drugs. It's the duty of the pharmacist to determine what drug is given and document it for future legal evidences.

​​How does Debit card processing work?

When the payment is initiated by the customer swiping Debit Card on POS device or entering Cards details such as Card Number, Expiry Date, CVV on App or website.
From this exchange, your point-of-sale system (POS system) reads the card information and transmits the data to the customer’s card processing network (Visa, MasterCard, etc.).
The processing network verifies the data and evaluates it for the possibility of fraud.
The processing network then sends the data to the issuing bank (i.e. the bank that issued the customer’s debit card).
The issuing bank confirms that enough funds are available and passes along an approval to the merchant or business owner.
Although this process may seem complicated, it occurs in only seconds — making debit cards (and credit cards) a very efficient form of payment.
The types of debit card processing are categorized by the way the card interacts with your POS system, and therefore, the way the data is transmitted and validated.
i.e.
PIN Debit Transactions
Signature Debit Transactions
Contactless Debit Transactions

​​What is The International Space Station?

The International Space Station is a large spacecraft. It orbits around Earth. It is a home where astronauts live.
The space station is also a science lab. Many countries worked together to build it. They also work together to use it.
The space station is made of many pieces. The pieces were put together in space by astronauts.
The ISS consists of pressurized modules, external trusses, solar arrays and other components. ISS components have been launched by Russian Proton and Soyuzrockets as well as American Space Shuttles.
The space station's orbit is about 220 miles above Earth. NASA and other space agencies uses the station to learn about living and working in space.
The first piece of the International Space Station was launched in 1998. A Russian rocket launched that piece. After that, more pieces were added. Two years later, the station was ready for people. The first crew arrived in October 2000. People have lived on the space station ever since. Over time more pieces have been added. NASA and its partners around the world finished the space station in 2011.
The purpose of the International Space Station is to provide an international laboratory to perform experiments within the space environment. For many of those experiments, the key parameter is prolonged weightlessness.
ISS is the ninth space station to be inhabited by crews, following the Soviet and later Russian Salyut, Almaz, and Mir stations as well as Skylab from the US. The station has been continuously occupied for 15 years and 32 days since the arrival of Expedition-1 on 2 November 2000. This is the longest continuous human presence in space, having surpassed the previous record of 9 years and 357 days held by Mir. The station is serviced by a variety of visiting spacecraft: Soyuz,Progress, the Automated Transfer Vehicle, the H-II Transfer Vehicle, Dragon, and Cygnus. It has been visited by astronauts, cosmonauts and space tourists from 20 different nations.

​​How do Ants sense Food?

Sugar has a slight odor, particularly granulated beet sugar. While all species of ants can differentiate between a wide variety of odors, the smelling range differs from a few centimeters to meters. Desert ants can smell sugar from up to 3 meters.
the food sources that ants cannot smell from a distance they 'smell' it (contact chemoreception) by touching it. So in a way, all the food they detect, they detect it by smelling. So yes, ants smell (although contact chemoreception is more like taste) the sugar.
The ant colonies send scout ants to search for food in various directions, often up to a range of 100 to 200 meters.(Depends on the territorial boundary and time of the year). The scout marches steadily in less circuitous paths initially if it has memories of previous feeder locations. (Ants use visual landmarks, and a stereo-smell system to create an odor map and navigate) Periodically it will halt and look for olfactory cues. It will then take into a more circuitous random search. And as it nears the sugar and can smell it, its search ends.
The antennae of ants have hair-like sensilia that contain one or more sensory neurons. Most of the sensilia contain olfactory neurons. Each neuron sends a long nerve fiber through the antennal nerve that terminate in the antennal lobe of its brain. The axons from the olfactory neurons terminate in the lobe in globular structures called glomeruli. The antennal lobe of ants is particularly large and it has around 420-430 glomeruli. (A honey bee has 160). The more the glomeruli, the more variety of odors the ant can process. This provides for the acute smell sense of ants.
Once food is found, the scout collects a little sample of it and marches back to the colony finding the shortest route and leaving a pheromone trail behind. Once in the colony the other ants analyse the food the scout brought and take the trail set by the scout. As more ants get on the trail, they make the marking stronger so that other ants who went out on searches can smell the trail and join them.
This sugar detection process is not entirely intuitive and needs to be learnt. A leader scout takes a willing pupil with it to teach how to search for food. The pupil walks behind the teacher in a paired march called tandem running. The pair stops from time to time so that the pupil can commit the landmarks to its memory. When the pupil is done, it taps on its master's hind legs or abdomen two times and they start moving again. (If you see a pair stop like that, you can tap the hind legs of the master ant with a hair and it will keep moving. If the distance between the pupil and the master gets too large the master slows down while the pupil runs to catch up).

​​Why do Old Books turn yellow?

Paper is made out of wood pulp which contains cellulose. Another organic substance binding the cells, fibers and vessels that constitute wood, is LIGNIN. Apparently, it is the most abundant renewable carbon source after cellulose.
Cellulose, a colourless substance, is remarkably good at reflecting light, which means we see it as being white.
To make a fine white paper (Bond paper), the wood pulp is put through a chemical process which separates and eliminates the lignin. This is why paper is usually white. However, when paper is manufactured, some lignin also ends up in it. Paper used as newsprint needs to be economical, and so ends up containing more lignin than other papers. Brown paper and cardboard used for packing purposes and as paper bags are stiff and strong because they also contain more lignin in them.
Paper is made from these components that yellow over time — at least when they're exposed to oxygen. But when lignin is exposed to light and the surrounding air, its molecular structure changes. Lignin is a polymer, meaning it's built from batches of the same molecular unit bonded together. In the case of lignin, those repeating units are alcohols consisting of oxygen and hydrogen with a smattering of carbon atoms thrown in.
Lignin, and in part cellulose, is susceptible to oxidation meaning it readily picks up extra oxygen molecules, and those molecules alter the polymer's structure. The added oxygen molecules break the bonds that hold those alcohol subunits together, creating molecular regions called chromophores which reflect certain wavelengths of light that our eyes perceive as colour. In the case of lignin oxidation, that colour is yellow or brown. So after oxidation we see paper as yellow or brown sheets.

​​What is Spectrum Auction?

The word spectrum in this context refers to a range of radio-waves that are used for communication purposes. This includes the FM or AM radio broadcasts that you listen to on the way to work, and even other wireless forms of communication like Bluetooth and Wi-Fi. The smartphone you're using also uses these same radio waves to transmit data, and the difference really lies in the specific frequencies in use, and of course, the technology used to convert those waves into something useful (whether that's the voice on the radio, the SMS you read, or the webpage you load).
The one characteristic you need to understand about spectrum is frequency - that's the number of repetitions of the wave you see in a second. You can easily understand this from the image below - the top-most wave is low-frequency, and so it repeats slowly. In the time that it makes three repetitions, the bottom-most (high-frequency) wave repeats 10 times. The high-frequency wave has obviously traveled a lot further in the same amount of time, but in a straight line, they've both gone as far - so the high frequency wave needs much more energy to travel the same distance. On the other hand, in the space it takes for three pieces of data in the first wave, you can fit 10 in the second, so you can pack more information into high-frequencies, in the same amount of time.
So spectrum refers to the waves that are there all around us at all times, passing through everything and this means that it needs to be regulated. If any one could broadcast signals at any frequency, there would be total chaos, and it would lead to a lot of interference, effectively rendering the spectrum useless for any kind of meaningful communication.
In a nutshell Spectrum is just the continuum of different frequencies that you can generate electromagnetic waves at, from a few kilohertz to a terahertz or more. The reason it's a scarce resource that needs to be managed and can be auctioned is that to send data at a certain rate, you need a range of spectrum of a certain minimum width, a.k.a. bandwidth. And all the transmitters in a particular area need to be using different, non-overlapping ranges of spectrum or there'll be interference. So there's a maximum amount of data that can be sent.

​​What is the difference between Earthing and Grounding?

Earthing and grounding are similar terms. Still, these are having many differences.

• Earthing means connecting the dead part (it means the part which does not carries current under normal condition) to the earth for example electrical equipment’s frames, enclosures, supports etc.
• The purpose of earthing is to minimize risk of receiving an electric shock if touching metal parts when a fault is present. Generally green wire is used for this as a nomenclature.
• Under fault conditions the non-current carrying metal parts of an electrical installation such as frames, enclosures, supports, fencing etc. may attain high potential with respect to ground so that any person or stray animal touching these or approaching these will be subjected to potential difference which may result in the flow of a current through the body of the person or the animal of such a value as may prove fatal.
• To avoid this non-current carrying metal parts of the electrical system are connected to the general mass of earth by means of an earthing system comprising of earth conductors to conduct the fault currents safely to the ground.
• Earthing has been accomplished through bonding of a metallic system to earth. It is normally achieved by inserting ground rods or other electrodes deep inside earth.
• Earthing is to ensure safety or Protection of electrical equipment and Human by discharging the electrical energy to the earth.

• Grounding means connecting the live part (it means the part which carries current under normal condition) to the earth for example neutral of power transformer.
• Grounding is done for the protections of power system equipment and to provide an effective return path from the machine to the power source. For example grounding of neutral point of a star connected transformer.
• Grounding refers the current carrying part of the system such as neutral (of the transformer or generator).
• Because of lightning, line surges or unintentional contact with other high voltage lines, dangerously high voltages can develop in the electrical distribution system wires. Grounding provides a safe, alternate path around the electrical system of your house thus minimizing damage from such occurrences.
• Generally Black wire is used for this as a nomenclature.
• All electrical/electronic circuits (AC & DC) need a reference potential (zero volts) which is called ground in order to make possible the current flow from generator to load. Ground is May or May not be earthed. In Electrical Power distribution it is either earthed at distribution Point or at Consumer end but it is not earthed in Automobile( for instance all vehicles’ electrical circuits have ground connected to the chassis and metallic body that are insulated from earth through tires). There may exist a neutral to ground voltage due to voltage drop in the wiring, thus neutral does not necessarily have to be at ground potential.
• In a properly balanced system, the phase currents balance each other, so that the total neutral current is also zero. For individual systems, this is not completely possible, but we strive to come close in aggregate. This balancing allows maximum efficiency of the distribution transformer’s secondary winding.

​​Why do Aeroplanes have Round shaped windows Not Square Or Rectangle?

As commercial air travel took off in the mid-20th century, airline companies began to fly at higher altitudes to save money—the air density is lower up there, creating less drag for airplanes. But for passengers to survive at 30,000 feet, the cabin must be pressurized.
To make that possible, the cabin was changed to a cylindrical shape to support the internal pressure. But at first, plane builders left in the standard square.
As a result of this, in the year 1953, two airplanes fell apart during flight which resulted in 56 causalities. After their investigation was done, it was concluded that the reason for the crash was the rectangle shaped airplane windows.
An aircraft fuselage is under a lot of stress when it rises from sea level to cruising altitude. It has to hold in a lot of pressure, which makes it flex slightly.
Repeated flexing leads to metal fatigue, which can eventually end with the fuselage breaking drastically one day.
This weak spot eventually becomes a potential danger as it can cause a mechanical failure and put the lives of people in peril.
Fortunately, designers figured out the design flaw pretty quick. Now we have nice, round windows that can withstand the pressure of cruising altitude.

​​How do the 3D Movies work?

If you look at an object near you and close your left and right eyes in turn, you’ll see that each has a slightly different view of the world. Your left eye sees a bit more of the left side of the object, and your right eye sees a bit more of its right side. Your brain fuses the two images together allowing you to see in three dimensions. This is known as stereoscopic vision.
To create a similar effect, 3D films are captured using two lenses placed side by side, just like your eyes (or by producing computer generated images to replicate the same effect).
In old fashioned 3D films, footage for the left eye would be filmed using a red lens filter, producing a red image, and footage for the right eye would be shot using a blue filter, resulting in a blue image. Two projectors then superimposed the images on the cinema screen.
3D glasses with blue and red filters ensured viewers’ left and right eyes saw the correct image: the red filter would only let red light through to your left eye, and the blue filter would only let blue light through to your right eye. Your brain would then combine these two slightly different images to create the illusion of 3D. Unfortunately, this meant that old fashioned 3D films couldn’t make full use of colour.
To get around this problem, modern 3D films use polarised light instead of red and blue light.
What is polarised light?
A polarised light wave vibrates on only one plane. The light produced by the sun is unpolarised, meaning it is made up of light waves vibrating on many different planes. It can however be transformed into polarised light using a polarising filter.
A polarising filter has tiny parallel lines etched into it, a bit like the slats on a set of venetian blinds. This means it will only let light vibrating on a particular plane through.
As with old fashioned 3D, the film is recorded using two camera lenses sat side by side. But in the cinema, the two reels of film are projected through different polarised filters. So images destined for viewers' left eyes are polarised on a horizontal plane, whereas images destined for their right eyes are polarised on a vertical plane.
3D glasses use the same polarising filters to separate out the two images again, giving each eye sees a slightly different perspective and fooling the brain.

​​What causes the Eiffel Tower to be slightly taller during the summer?

Eiffel Tower, French Tour Eiffel, Parisian landmark that is also a technological masterpiece in building-construction history. When the French government was organizing the International Exposition of 1889 to celebrate the centenary of the French Revolution, a competition was held for designs for a suitable monument. 
More than 100 proposals submitted by the greatest international architects, the French government chose the one from Gustave Eiffel, the French engineer best known for his construction of metal bridges and for contributing to the design of the Statue of Liberty.
His proposal won for its originality and for its technical aspects. 18,038 iron parts and 2.5 million rivets were needed for its assembly.
Beyond the controversy, the work involved, and the complexity of the structure, the story of the Eiffel Tower is steeped in legends and curiosities.
Chief among these is the variability of its height.
The tower itself is 300 metres (984 feet) high. It rests on a base that is 5 metres (17 feet) high, and a television antenna atop the tower gives it a total elevation of 324 metres (1,063 feet). 
Due to the thermal expansion of the metal that occurs during the summer time, the Tower grows an average of 15 centimetres (six inches) during the hottest months. The greatest growth on record occurred in 1976, when this heat-induced expansion added another 18 centimetres (seven inches) to the tower’s 324 metre height.
Another curious element regarding this beautiful monument is its repainting, a process that takes place, on average, every seven years. The tower has changed colors numerous times, moving from Venetian red, to ochre yellow, to chestnut brown, and finally to its current bronze, chosen as recently as 1968.

​​Why do some Trucks have one Pair of Tires hanging in the air and not touching the road?

Trucks have extra axles that move up and down depending on how much weight is on the truck.
Trucks will lower the axles when loaded to reduce pressure on the road as the load is spread out over more axles and tires. On trucks such as concrete mixer trucks, these axles look like trailers hanging off the back, and they are only lowered when the truck is loaded. Other axles, such as on large dump trucks, are in the middle of the truck and only move up and down.
There are also large busses that have what are called “tag” axles in the rear, these are single tire axles that move up and down and turn when the bus is making a tight turn, allowing it to maneuver in tight spaces. That is how those busses navigate inner city streets and traffic with such ease, they steer from the front and rear. Some specialized trucks have rear steer axles, such as fire trucks.
For trucks, it is all about weight distribution. For the same reason, when you see a heavy haul truck and trailer there will be many more axles than normal, all according to the load on the truck. When you see a trailer with more than the standard two axles, that is also to allow the trailer to haul extra weight, such as a milk tanker truck. However, they remain down all the time instead of moving up and down.

​​Why is a 'Red Cross' used as a medical symbol?

The sign of the Red Cross is associated with Red Cross Society, which is a voluntary organisation in the field of medical services. It was founded by Henry Dunant about 150 years ago. The sign is always found on hospitals, nursing homes, clinics, dispensary, ambulances, etc. The Blue Cross was introduced in the US but it is not as popular as the Red Cross, which is found worldwide. The reason crosses are used and associated with medical professions is mainly because of its use by the International Red Cross Society The  Red Cross emblem was based on the design of the Swiss national flag. The red cross emblem can’t actually be used by doctors or anyone else, as it’s regarded as an internationally protected symbol.
The international Red Cross organization had won noble prize for its work for three times.  Coming to the matter, red cross is named for offering unconditional help to the people in need.  So, medical field, which also offers life saving services to the people adopted this symbol. That is the reason why hospitals and ambulances use red color plus symbol.

​​What is use of Calcium Carbide in fruits?

Ripening is a process in fruits that causes them to become more palatable. In general, fruit becomes sweeter, less green (typically "redder"), and softer as it ripens. 
Ripening agents accelerate ripening. An important ripening agent is ethylene, a gaseous hormone produced by many plants. Many synthetic analogues of ethylene are available They allow many fruits to be picked prior to full ripening, which is useful since ripened fruits do not ship well. For example, bananas are picked when green and artificially ripened after shipment by being exposed to ethylene.
Calcium carbide is also used in some countries for artificially ripening fruit. When calcium carbide comes in contact with moisture, it produces acetylene gas, which is similar in its effects to the natural ripening agent, ethylene. Acetylene accelerates the ripening process. Catalytic generators are used to produce ethylene gas simply and safely. Ethylene sensors can be used to precisely control the amount of gas. Covered fruit ripening bowls or bags are commercially available. These containers increase the amount of ethylene and carbon dioxide gases around the fruit, which promotes ripening.
Ripening indicators like Iodine (I) can be used to determine whether fruits are ripening or rotting by showing whether the starch in the fruit has turned into sugar. For example, a drop of iodine on a slightly rotten part (not the skin) of an apple will stay yellow or orange, since starch is no longer present. If the iodine is applied and takes 2–3 seconds to turn dark blue or black, then the process of ripening has begun but is not yet complete. If the iodine becomes black immediately, then most of the starch is still present at high concentrations in the sample, and hence the fruit hasn't fully started to ripen.

​​How do QR codes work?

QR codes are a technology that desperately wants our attention. They appear everywhere from supermarket shelves and magazines to hiking trails and tombstones.
QR (Quick Response) code is the trademark name for the two dimensional barcode system. It was originally invented in 1994 by Denso Wave, a Toyota subsidiary, as a way to track vehicles as they were assembled, and to scan components at high speeds. While Denso Wave does hold the patent on the technology, it has granted free licence on it, going so far as to publish the spec online, and allowing anyone to use it.
The conventional one dimensional barcodes used on virtually every consumer product are mechanically scanned. That is, they're read by physically bouncing a narrow beam of light onto the code, which can be interpreted using the pattern of light reflected off the white gaps between the lines.
A QR code works by encoding data in a certain way (a certain standard) so scanning software can interpret the results. For example, normal barcodes on products are considered 1D barcodes. The lines are different widths that correspond to numbers. Software interprets those line widths as numbers.
Same with the QR code; the location of each block is interpreted by the software and the combination of a bunch of blocks combine to represent certain characters. Combine the characters and you can get a URL for example.
If you add logic in the scanning software that opens a browser and goes to the link when the encoded data looks like a URL (with http://), you have added the functionality of translating printed material into digital material.

​​What are the small red lights around the CCTV cameras?

Those small red lights around the CCTV cameras are called IR LED or simply infrared LED. They're used to supply lighting for security cameras to see in dark and low light conditions which are turned off at day time. Through those small red lights, cameras can be able to capture images at dark by means of infrared.
Infrared light is part of the spectrum of light that is invisible to the naked human eye. It is, however, visible to security cameras. Those LED emitters are actually outputting infrared light. This means that at night, even when you can’t see anything, and it’s completely dark, your security camera can see what’s going on. You might have seen this when your security camera switches from day to night vision; you can see the infrared illuminator come on, perhaps with a little clicking sound.