Observation in the natural sciences is an act or instance of noticing or perceiving and the acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the perception and recording of data via the use of scientific instruments. The term may also refer to any data collected during the scientific activity. Observations can be qualitative, that is, the absence or presence of a property is noted and the observed phenomenon described, or quantitative if a numerical value is attached to the observed phenomenon by counting or measuring.
Observing the air traffic in Rõuge, Estonia
Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repeatability of findings are used to try to ensure the validity of scientific advances.
Onion (Allium) cells in different phases of the cell cycle. Growth in an 'organism' is carefully controlled by regulating the cell cycle.
Plato (left) and Aristotle in a 1509 painting by Raphael. Plato rejected inquiry into natural philosophy as against religion, while his student, Aristotle, created a body of work on the natural world that influenced generations of scholars.
Johannes Kepler (1571–1630). Kepler's Astronomia Nova is "the first published account wherein a scientist documents how he has coped with the multitude of imperfect data to forge a theory of surpassing accuracy", therefore laying the groundwork for the scientific method.
Isaac Newton is widely regarded as one of the most influential scientists of all time.