Adilson de Oliveira argues that we are so used to technological devices that sometimes even stop to think about how things work. According to the physicist, behind most of the devices that make our lives today are very old discoveries, mainly related to magnetism.
Some technologies, as incorporated into our daily lives, seem invisible: we barely even stop to think about how they work, or how much research was needed to be created. It’s like were always been there. Who has about 40 years or less, for example, think natural to have home one (or a few) color television sets, whose popularity has intensified in the 1970s Younger then were born immersed in several other technologies: cordless phones, VCRs and microwave, which invaded the houses there in the 1980s; DVD players, computers, cell phones and the Internet itself, whose spread has intensified in the 1990s Which speak of children and adolescents today, born amid the smartphone and tablets strolling in cars with onboard computers and watching TV in high definition and three dimensions?
In the midst of so much technology, advancing as quickly as is incorporated into our lives, it is difficult to remain aware of how each device works. Most end up facing these machines as black boxes, in the sense that it is not known what actually there inside – which, of course, is not true: for every technological contraption that today bought mankind needed, throughout its history to develop mechanisms, simple or complex, able to make it work.
An important part of this technology in our homes has become possible from the basic research of matter and their interactions, in other words , the study of what we call “basic science”
If you think about it, we see that man has always tried to turn phenomena, materials and objects to make your life easier. Back then, we discover how to master the fire and build instruments and tools using chipped stone and metals. Today, we are able to produce new physical phenomena and assemble new materials atom by atom, using nanotechnology. A big road traveled …
An important part of this technology our homes has become possible from the basic research of matter and their interactions, in other words, the search of what we call “basic science”. In particular, many devices and equipment are based on the magnetism of matter, a phenomenon known since ancient times.
Science coming from antiquity
It all started with a stone found in the Magnesia region in Greece, which acts as a natural magnet. The Greek philosopher Thales of Miletus was the first to propose an explanation for this to happen: to see that the magnetite now being attracted, now repelled, attributed the behavior to the fact that the stone would possess a “very soul”. Later, Plato tried to explain the magnetic phenomena admitting that the attraction and repulsion were due to “moisture” and “dryness” of magnetite.
A few hundred years ahead, the 19th century was also a period of great advancement in science. In particular, this time it was discovered that the electric and magnetic phenomena were associated. The Frenchman André-Marie Ampère and Dutchman Hans Christian Oersted found that electrical currents generate magnetic fields, allowing further study of magnetism and electricity. The Englishman Michael Faraday and the American Joseph Henry independently, discovered the law of electromagnetic induction, showing that magnetic fields that vary over time produce electrical currents – property that allowed the development of generators and electric motors, indispensable today. There are about 2000 years, the Chinese realized that these “stones with himself” if left free to roam, tended to be aligned in a specific direction, serving as a tool for guidance. Came the compass, whose operation is based on the interaction between the magnetic fields of the magnet and the Earth. Incorporated into ships and used to guide long trips, this technology allowed the Europeans to do the first major planetary exploration history in the 15th century.
-
- Magnetic materials and their interactions with the electric and magnetic fields They allowed the emergence of many of our everyday facilities. (photo: Windell Oskay / Flickr CC BY 2.0)
In the second half of the same century, in 1873, Scotsman James Clerck Maxwell unified these findings and also showed that light is a form of radiation electromagnetic, that is, it is due to oscillations of electric and magnetic fields. A few years later, in 1888, the German physicist Heinrich Rudolph Hertz produced electromagnetic waves, proving Maxwell’s theory. These studies soon deployed technologies, especially the development of wireless telegraph and radio. Even current cell still make use of this knowledge, receiving and transmitting information to towers that connect to each other and to the satellites via electromagnetic waves.
Still in the 19th century, we began the development of the first devices magnetic recording. The Danish engineer Valdemar Pouslen in 1898 created the first voice recorder magnetizing a steel wire. Although not made recordings with the high quality that we demand today, the device used a very simple principle: being the sound of our voice a spread of mechanical waves in the air, the microphone picked up these disturbances, making vibrate a magnet magnetized steel wire , passed slowly. To reproduce the sound used is the reverse process. – The wire to move attracted or away from the magnet, causing it to produce a vibration on a surface to generate the sound
Magnetism in the digital world
The computer hard drives usually magnetize small regions in the order of hundreds of nanometers in size (one nanometer is the billionth of a meter). The recording of each piece of information is done through the application of magnetic fields on the material that makes up the hard drives
Currently, the magnetic recording processes are much more sophisticated and can use them to store and process information . The computer hard drives typically rely this process, magnetizing small regions in the order of hundreds of nanometers in size (one nanometer is the billionth of a meter). The recording each piece of information is performed by applying a magnetic field over the material that makes up the hard disks. In them, the information is written in the form of a binary code, as a sequence of “0″ and “1″ (can be represented, for example, the “0″ as a small magnet with the north pole pointing up, or the “1″ with the pole pointing down).
You for reading the recorded information, it uses a technology based on quantum phenomenon of giant magnetoresistance, discovered in the 1980s It occurs when produce thin layers of atoms of only a few nanometers thick, alternating magnetic and non-magnetic materials. Depending on how much the magnetic layers are separated, they may have a parallel orientation (both the north and south poles in the same direction) or antiparallel (each layer with opposite orientations).
In the second case, that of a layer in the anti-parallel situation, as we do with an electric current to pass through the material, we see that this offers a certain resistance to current flow. By applying a magnetic field to the layer which is oriented in the opposite direction, its poles are reversed to align the direction in which the magnetic field is applied. When this occurs, the resistance to the electrical current of this material may range up to tens of times.
This allowed the information storage capacity on personal computers spend a few megabytes in the years 1980 to terabytes today. For this discovery, the French physicist Albert Fert and the German Peter Grünberg won the physics Nobel prize in 2007.
The list of technologies that utilize magnetic phenomena and materials is large and includes televisions, ovens microwave and automobiles, among others. In addition, recent discoveries of new materials have allowed the emergence of new applications and devices. Anyway, human curiosity to understand the nature, aligned with its ability to innovate and invent, allows us modify our daily lives with our creations. The challenge is to do this always thinking about the well being of humanity as the technologies unfortunately also can be applied in perverse ways.
Adilson de Oliveira
Department Physical
Federal University of São Carlos
No comments:
Post a Comment