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Why Hot Water Freezes Faster than Cold Water

Why Hot Water Freezes Faster than Cold Water 86

The fact that preheated liquids freeze faster than those that are already cold was observed for the first time by Aristotle in the 4th century AD.

A team of researchers from Universidad Carlos III de Madrid, the Universidad de Extremadura and the Universidad de Sevilla have defined a theoretical framework that could explain the Mpemba effect, a counterintuitive physical phenomenon revealed when hot water freezes faster than cold water.

The researchers, who have recently published the findings in Physical Review Letters, have confirmed how this phenomenon occurs in granular fluids, that is, those composed of particles that are very small and interact among those that lose part of their kinetic energy. Thanks to this theoretical characterization, “we can simulate on a computer and make analytical calculations to know how and when the Mpemba effect will occur,” said Antonio Lasanta. Lasanta is from the UC3M Gregorio Millán Barbany University Institute for Modeling and Simulation on Fluid Dynamics, Nanoscience and Industrial Mathematics. “In fact,” he said, “we find not only that the hottest can cool faster but also the opposite effect: the coldest can heat faster, which would be called the inverse Mpemba effect.

The fact that preheated liquids freeze faster than those that are already cold was observed for the first time by Aristotle in the 4th century AD. Francis Bacon, the father of scientific empiricism, and René Descartes, the French philosopher, were also interested in the phenomenon, which became a theory when, in 1960, a Tanzanian student named Erasto Mpemba explained to his teacher in a class that the hottest mixture of ice cream froze faster than the cold one. This anecdote inspired a technical document about the subject, and the effect began to be analyzed in educational and science magazines. However, its causes and effects have hardly been studied until now.

“It is an effect that, historically, has not been addressed in a rigorous manner but merely as an anomaly and a didactic curiosity,” said Antonio Prados, one of the researchers from the Universidad de Sevilla Department of Theoretical Physics. “From our perspective, it was important to study it in a system with the minimum ingredients to be able to control and understand its behavior,” he said. This has enabled them to understand what scenarios it is easier to occur in, which is one of the main contributions of this scientific study. “Thanks to this, we have identified some of the ingredients so that the effect occurs in some physical systems that we can describe well theoretically,” stated researcher Francisco Vega Reyes and Andrés Santos, from the Universidad de Extremadura Instituto de Computación Científica Avanzada (Institute of Advanced Scientific Computation).

“The scenario that the effect will most easily occur in is when the velocities of the particles before heating or cooling have a specific disposition — for example, with a high dispersion around the mean value,” he said. This way, the evolution of the temperature of the fluid can be significantly affected if the state of the particles is prepared before the cooling.

This research of “basic science,” in addition to contributing to improving fundamental knowledge, might have other applications in the mid or long term. In fact, this group of researchers is planning to carry out an experiment that verifies the theory. Learning to emulate and use this effect might have applications in our daily life, according to scientists. For example, it could be used to make electronic devices which we want to cool faster.

Video (Spanish with English subtitles):

Journal Reference:
Antonio Lasanta, Francisco Vega Reyes, Antonio Prados, Andrés Santos. When the Hotter Cools More Quickly: Mpemba Effect in Granular Fluids. Physical Review Letters, 2017; 119 (14)

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The goal of human civilization is to create AI and disappear?

The goal of human civilization is to create AI and disappear? 87

Various sources often talk about civilizations that lived long before us. They all developed, prospered for a while, and then disappeared in an incomprehensible way. 

What is the reason for their decline, we probably will not know. All we can do is admire the remains of stone buildings, over which time has almost no power.

While looking for an answer, we somehow accidentally stumbled upon an interesting saying about the life of Japanese samurai: “A samurai has no goal, but a path.” In the end, the “path of the samurai” ended in what is known – death. The path of any civilization ended in the same way.

If you look at the issue through the prism of a samurai saying, then there is no point in looking for why and how civilization ended its existence. Probably, the process itself and its result are important here. But to whom is it important and what result does it expect?

Mysterious director

Apparently, behind the curtains of this “ancient theater” there is a mysterious “director” who periodically makes necessary adjustments to the history of civilization.

To figure out what’s what, you need to look at current trends in science. Where does a person strive with such an irresistible desire to “play God.” This attracts him and at the same time frightens him, but in no way turns him away from the intended path. Most likely, artificial intelligence (AI) is the purpose of our civilization’s existence.

About 50 years ago it would have seemed nonsense, but to someone, perhaps even now. However, if you trace the last 100 years of the life of our civilization, you get the feeling that most of the discoveries were given to mankind at the same time. A powerful leap has taken place in a hundred years. Why did it happen?

At the beginning of the last century, scientists recognized the existence of fields that have memory and the ability to store and transmit information. It is very likely that such or a similar field can be around the Earth and, more interesting, possess intelligence. Isn’t this the same “Director” hiding behind the screen of the “ancient theater”?

If this is so, then at a certain moment the “Director” gives the selected scientist “access” to certain knowledge (perhaps even in a dream, like Mendeleev), and another scientific breakthrough occurs in the world. Step by step, discovery after discovery, humanity is steadily moving towards the creation of AI. The trend is already well visible.

The goal of human civilization is to create AI and disappear? 88

AI is probably the next “Babylon”, which will combine all the knowledge, culture and accumulated experience of civilization. In the future, the neural network will enter into a connection with the general information field and leave humanity without knowledge, technology, and even a spoken language. This will be the next decline of civilization. And the “Director” will receive another array of new data (experience) in order to start creating a new civilization.

If someone believes that past civilizations ended in large-scale conflicts, then most likely this is already the consequences of “turning off” AI.

Co-founder of Skype talked about the threat of AI to humanity

One of the creators of the Skype internet call service, Jaan Ta

The goal of human civilization is to create AI and disappear? 89
© still from the movie “Terminator 2: Judgment Day”

llinn, said that the development of artificial intelligence (AI) threatens humanity. According to him, humans face three key threats, but it is AI that should be feared most of all, the expert said. 

Tallinn explained that at the moment, no one can predict what development AI will achieve in the next decades. In addition, the fact that scientists are creating artificial intelligence that can form a new AI without human intervention is also a cause for concern.

In addition, as the co-founder of the popular video calling service noted, the development of synthetic biology also causes concern. According to him, this direction in science allows the creation of artificial DNA sequences and biological systems that may not exist in nature.

Tallinn also drew attention to the fact that he fears we are entering an era of “unknown unknowns”, things that people are not even able to imagine right now.

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Volkswagen robot will autonomously charge cars: a working prototype presented

Volkswagen robot will autonomously charge cars: a working prototype presented 90
Copyright: © VW

The renowned German car manufacturer announced a new development. This time, engineers have created a unique robot capable of autonomously charging electric vehicles. 

For more than a year, specialists have been developing this project, but only now the concern was ready to demonstrate the first working prototype. The robot is ready to charge electric vehicles and has shown the high efficiency of this process.

It is called the Mobile Charging Robot, and experts have already compared it to the R2-D2 droid from Star Wars, including squeaks and clangs. Indeed, there is a similarity. Before implementing this idea, the engineers decided that robots should be allowed to charge cars parked in large residential complexes.

This will save their owners from leaving in order to find a gas station. Another advantage is that large parking lots and garages do not have to contain several expensive charging points for electric cars. The car company said in a press release that the robot works exclusively autonomously.

It independently controls and interacts with the vehicle being charged. It opens the cover of the charging socket and independently connects the power plug, then disconnects it. The robot looks like a trailer, which is a mobile energy storage.

It is capable of charging multiple electric vehicles at the same time. Despite the fact that the manufacturer confidently praises its concept, experts saw inefficiency in the fact that first it is necessary to charge the robot’s battery, which is then used to recharge electric cars.

Volkswagen Group Components CEO Thomas Schmall noted that creating an efficient charging infrastructure for the cars of the future is an important step in the company’s development.

Its engineers focus on finding solutions to avoid costly do-it-yourself measures. The mobile robot is only part of the concept that will continue to be developed.

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This video will forever change the way you think about time

This video will forever change the way you think about time 91

Business Insider, one of the world’s leading news portals, made a three-minute video that depicted the Earth’s timeline as a journey from Los Angeles to New York.

So, the beginning of the journey is 4.54 billion years ago, when the Earth was formed from the accumulation of gases and stardust. After some time, a significant event occurs – a giant space body crashes into the still not cooled Earth, as a result of which the breakaway part becomes its satellite – the Moon.

Further, the route runs through the mountains of Arizona, formed about 3.95 billion years ago. A few more kilometers to the east and we are at the 3.8 billion year mark. This is where the first evidence of life in the form of replicating molecules appears.

The next “stop” Kansas – 2.7 billion years ago. Cyanobacteria that produce oxygen appeared on Earth. It took the next 200 million years for the atmosphere of our planet to accumulate sufficient reserves of this most important gas.

Halfway through, we reach Pennsylvania. We are separated from it “only” by 660 million years. Life is developing rapidly: the Earth is covered with vegetation, amphibians are evolving. Unusual time travel is coming to an end – to the point “Now”. By the time the dinosaurs become extinct, we finally reach the outskirts of New York.

And where is the most important thing – people? To find out, you need to carve out three minutes and watch the entire video.

Source: Business Insider

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