Observations, examinations and experiments
Some scientists, especially astronomers, observe; this is the most difficult skill in science. In terrestrial-based astronomy, telescopes look out through a moving atmosphere, which is by no means a perfect lens. From second to second it changes its astigmatism; it has a prism effect one moment, a cylinder the next. Observing stars and planets through such an ordinary, terrestrial-based telescope shows an image that jiggles about. Approaching such observations with an idea in mind, a hypothesis about what is happening, is a necessary preliminary to any observational science. Observation and successful prediction is the bread and butter of science. Deficit experiments are the cheese, but can occur without the pickle of good controls. Experiment is usually possible in addition to observation and prediction, examining both less and more to expose the answers to simple questions. Doing an experiment doesn’t change the nature of the universe – it is unbearably complicated, just as when making observations.