Science, from latin " scientia" (knowledge) and "scire" (to know) is a broad term used to describe "the intellectual and practical activity encompassing the systematic study of the structure and behaviour of the physical and natural world through observation and experiment." [New Oxford Dictionary of English]
Science therefore is occupied with the gathering of systematic, i.e. structured, knowledge about the world we live in. We can distinguish two main types of science: a) experimental science (the "why?") and b) applied science (the "how?"). Both are separate scientific approaches, but also influence each other. Science can equally be divided in the different fields of research, such as natural sciences (for example mathematics, biology, physics) and social sciences (for example history, sociology and psychology). Each of these sciences can exist in several or all of these groups. For example the mathematical sciences can have an experimental or theoretical approach (pure science) and its results can be applied in a practical field such as population statistics (applied science) in the field of sociology (social science).
Science works by observation, experiment, evaluation and prediction. It tries to discover and formulate laws that are able to predict the outcome of similar situations, problems and experiments in future. For example, an experiment regarding the effectiveness of a certain antibiotic towards a certain bacteria has as the ultimate goal to find a reliable treatment for diseases caused by such bacteria, without the need to repeat the experiment before each treatment.
A short history of science
The oldest scientific approach has been the observation and the intent to formulate on the basis of the observed facts a scientific or natural law. Science in this early stage was connected especially with ancient Greek philosophy (Aristotle, Pliny the Elder and the like). In the Mediaeval Ages, centers of science were the monasteries in Europe, and especially the emerging islamic universities in Europe (Spain) and Asia. The real scientific revolution started during the Renaissance and Enlightenment, when the fields of sciences, such as biology and astronomy, were developed and defined. Scientific methods were developed and basic universal measurements, such as the meter, agreed on. Inventions and the scientific approach of
allowed the sciences to develop further and further as their findings were helpful to research deeper and deeper. An example, applied sciences like mathematics and engineering have allowed the building of more and more powerful computers which, in reverse, allowed the research of mathematical problems in more depth.