SciencewithD

TRAFFIC LIGHT SIGNALS Traffic lights   is a set of automatic,coloured lights for controlling traffic. Traffic lights are signaling devices positioned at road intersection, pedestrian crossing , and other locations to control the flows of traffic. We all have stuck in traffic jam and observed the traffic lights which give us signal :           Red - Stop,when to stop          Yellow (Amber) - Caution , go slow             Green -go,  move    by changing colour.  What is the reason behind the use of  Red  ,  Yellow  and  Green in traffic light signals ? Red   was considered as the signal of danger from ages due to colour of  Blood  and  Fire since long. Red colour can be seen from   large distance due to its longest wavelength in visible spectrum and less scattering character. Yellow   has wavelength next to red colour so it has also least scattering properties and can be seen from large distances.Yellow light can be easily visible in night and it also offer most

Science is broadly classified into two categories:  Natural Sciences or Real Science                                        Social Science Natural Science is the branch of science which deals with the study of universe (living organisms and non living systems) each and every thing.The law and theories in natural science does not change with place,people and time.So, its a study of  unchanged reality. Example : If an experiment is performed(correctly and accurately) by me or you its result does not change. Social Science is the systematic study of human behaviour and society. It is changing reality. Example: Economy of different countries is different. Initially, Science is studied under Philosophy .  But with the passage of time, as the man acquired more knowledge and experiment to validate facts(philosophy) science is considered as separate subject. In universe subject matter of Natural Science (Real Science) is studied  under two categories Living Organism and

Science word is derived from a Latin word Scientia , which mean ' to know ' or 'knowledge' . Definition of Science  Science is an organised , systematic and formulated knowledge obtained through observations, experiments and verifications .  Science is the systematic study of the structure and behaviour of the physical and natural world through observation and experiment.It is an organised body of knowledge on an object. According to Einstein ," Science is an attempt to make the chaotic diversity of our sense experience correspond to logically uniform system of thought". According to Webster's New Collegiate Dictionary " Science is knowledge covering general truths of the operation of general laws, esp. as obtained and tested through scientific method concerned with the physical world." Scientific Method : The procedure , which the scientists use in the pursuit of science is known as scientific method. It consists of systematic ob