Watch videos with subtitles in your language, upload your videos, create your own subtitles! Click here to learn more on "how to Dotsub"

Energie physikalisch

0 (0 Likes / 0 Dislikes)
All our lives are determined by the use of energy. The term energy – as well as work, force or power – colloquially often has a meaning different from that in physics The term energy as well as work, force or power colloquially often has a meaning different from that in physics Physically speaking, energy is the ability to do work no matter whether in the form of mechanical, electric, chemical or thermal energy In mechanics, for example, work is defined by the force necessary to move a body a certain distance So work is the product of force and displacement Work = force · displacement or W = F ·s In physics work is measured in newton metres As mechanical energy can be converted into thermal energy or electrical energy the unit 1 newton metre can also be indicated as 1 joule or 1 watt-second In the physical sense, there is no energy generation and no energy consumption on earth The energy available just changes its manifestations The Law of Energy Conservation states In an isolated system, where a random number of mechanical thermal, electrical, optical or chemical processes occur the total amount of energy remains constant The energy we use as consumersvarious transformations for example in the form of petrol or electric current, has usually covered a long distance already and even under- gone and even undergone As primary energy we denote the naturally-occurring forms of energy such as the fossil sources of energy crude oil, coal or gas nuclear energy in uranium and the renewable energies wind, biomass, solar energy and water power In this natural form energy can rarely be used It must first be extracted, as it were, and utilized Conversion processes in refineries or power stations, flawed with losses supply us with secondary energy As diesel and petrol, we use it as fuel for our cars. Or it is available as electric current generated in power stations. This form of energy can be transported or stored easily Or it is available as electric current generated in power stations This form of energy can be transported or stored easily But for energy to be usable for final consumers, often an additional conver- sion process is needed, which again reduces its utility. This final energy now makes light bulbs shine, water boil and cars go. Sockets and gas connec- tions make our modern life possible often an additional conversion process is needed , which again reduces its utility. This final energy now makes light bulbs shine, water boil and cars go. Sockets and gas connec- tions make our modern life possible This final energy now makes light bulbs shine, water boil and cars go Sockets and gas connections make our modern life possible Thus we utilize the energy provided. We prepare our food and settle down comfortably in front of our TVs. We can feel energy in our houses in the form of warmth, especially in winter. Without the mobility provided by cars our world would be unimaginable today We prepare our food and settle down comfortably in front of our TVs We can feel energy in our houses in the form of warmth, especially in winter Without the mobility provided by cars our world would be unimaginable today Warmth, light or movement are perceptible forms of useful energy Whenever energy is utilized or converted,that is, when work is being done we talk about power The physical formula goes power = work / time = energy / time or P = W / t So a technical system releasing a lot of energy in a short time performs well, for example a power station of 600 MW (megawatts) The power of a horse used to be called hp it was equivalent to 736 watts Decisive for every technical system is its degree of efficiency The ratio of power input to power output The degree of efficiency eta can only move between 0 and 1, or else between 0 % and 100 % Whereas a coal-fired power station for example, has a degree of efficiency of below 50 % a hydroelectric power station yields up to 90 % An electric light bulb, when shining, reaches a degree of efficiency of only 4 %; used as a heater, it would yield around 96 %. From that point of view, it performs at a power loss of 96 % as a light source used as a heater, it would yield around 96 % From that point of view, it performs at a power loss of 96 % as a light source In every technical system losses are constantly incurred that means the de- gree of efficiency can never be above 100%. That is also why the dream of mankind of an automotive vehicle – a perpetual motion machine – will remain a dream forever That is also why the dream of mankind of an automotive vehicle – a perpetual motion machine – will remain a dream forever Energy is not needed evenly Just like on our roads, there are peak times and calm periods in energy consumption In the morning, at noon and in the early evening, we need energy the most At that time we cook, take showers and watch the news on TV Of course, on working days we need more energy than on weekends and in winter more than in summer A certain amount of energy, however is always required independently of hours or events Man nennt diese ständig benötigte Energiemenge die Grundlast. Im Gegen- satz dazu werden die höchsten Werte des täglichen Energieverbrauchs Spit- zenlasten genannt It is needed for example to supply street lamps and traffic lights as well as appliances of a hospital intensive care unit In contrast, the highest amounts of daily energy consumption are called peak load. Once again Even though we talk about energy consumption or energy loss energy never gets lost in actual fact During all energy conversion processes warmth is released into the surrounding space and thus the usable energy is reduced This also means a constant increase of entropy

Video Details

Duration: 7 minutes and 35 seconds
Country: Germany
Language: German
Genre: None
Views: 71
Posted by: manfredwolf on Apr 30, 2010

....

Caption and Translate

    Sign In/Register for Dotsub to translate this video.