domingo, 20 de enero de 2019

The Story of Electricity - BBC Documentary



Electricity is the physical flow of electrons, referred to as an electrical current. Electricity is an energy carrier that efficiently delivers the energy found in primary sources to end users, who in turn convert it into energy services. Electricity is all around us–powering technology like our cell phones, computers, lights, soldering irons, and air conditioners. It’s tough to escape it in our modern world. Even when you try to escape electricity, it’s still at work throughout nature, from the lightning in a thunderstorm to the synapses inside our body. But what exactly is electricity? This is a very complicated question, and as you dig deeper and ask more questions, there really is not a definitive answer, only abstract representations of how electricity interacts with our surroundings. Electricity is a natural phenomenon that occurs throughout nature and takes many different forms. In this tutorial we’ll focus on current electricity: the stuff that powers our electronic gadgets. Our goal is to understand how electricity flows from a power source through wires, lighting up LEDs, spinning motors, and powering our communication devices. Electricity is briefly defined as the flow of electric charge, but there’s so much behind that simple statement. Where do the charges come from? How do we move them? Where do they move to? How does an electric charge cause mechanical motion or make things light up? So many questions! To begin to explain what electricity is we need to zoom way in, beyond the matter and molecules, to the atoms that make up everything we interact with in life. This tutorial builds on some basic understanding of physics, force, energy, atoms, and fields in particular. We’ll gloss over the basics of each of those physics concepts, but it may help to consult other sources as well. Electricity can be created in three ways: The most common is through electro-magnetic conversion, where electricity is generated by moving an electric conductor, such as a wire, inside a magnetic field. The most practical example of this method is a generator connected to a turbine. The turbine provides the motion required to move the conductor in the generator. This energy for motion can come from various technologies, for example wind turbines, hydropower, or the steam created from heat produced in nuclear fission or coal combustion. Electricity can also be created through a chemical reaction, for example in a battery or fuel cell. Finally, electricity can be created through solid-state conversion, wherein electricity is generated using the structure and properties of a solid. The specially constructed solid consists of different molecules packed closely together that create an electric current when stimulated. An example of a technology that utilizes solid state conversion is a solar PV cell.

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