Introduction
Wonders a useful inventions. Many people would like to contribute to society deserve the way forward it to his invention to help facilitate life and of course, improve its standard. Sometimes we may meet with negative inventions, such as weapons, but above all, that is negative to the invention is a contribution of people who improperly handle the invention, as its designers certainly did not want that to be the man he uses, namely to defense. There are many inventions, which of course are very positive and almost indispensable in today's times. I mean electricity, which is an excellent example of the invention, without which a man today I cannot imagine life. Sometimes inventions allow man to develop ever-newer areas of technology, as it has to do with mechanical machines, for example, cars or airplanes, which are very commonly used by humans.