Ideas and Evidence in Science !!

In some of the investigations you perform in the school laboratory, you may find that you do not interpret your data in the same way as your friends do; perhaps you will argue with them as to the best way to explain your results and try to convince them that your interpretation is right. Scientific controversy frequently arises through people interpreting evidence differently. Observations of the heavens led the ancient Greek philosophers to believe that the Earth was at the centre of the planetary system, but a complex system of rotation was needed to match observations of the apparent movement of the planets across the sky. In 1543, Nicolaus Copernicus made the radical suggestion that all the planets revolved not around the Earth but around the Sun. (His book On the Revolutions of the Celestial Spheres gave us the modern usage of the word ‘revolution’.) It took time for his ideas to gain acceptance. The careful astronomical observations of planetary motion documented by Tycho Brahe were studied by Johannes Kepler, who realised that the data could be explained if the planets moved in elliptical paths (not circular) with the Sun at one focus. Galileo’s observations of the moons of Jupiter with the newly invented telescope led him to support this ‘Copernican view’ and to be imprisoned by the Catholic Church in 1633 for disseminating heretical views. About 50 years later, Isaac Newton introduced the idea of gravity and was able to explain the motion of all bodies, whether on Earth or in the heavens, which led to full acceptance of the Copernican model. Newton’s mechanics were refined further at the beginning of the twentieth century when Einstein developed his theories of relativity. Even today, data from the Hubble Space Telescope is providing new evidence which confirms Einstein’s ideas. Many other scientific theories have had to wait for new data, technological inventions, or time and the right social and intellectual climate for them to become accepted. In the field of health and medicine, for example, because cancer takes a long time to develop it was several years before people recognised that X-rays and radioactive materials could be dangerous. At the beginning of the twentieth century scientists were trying to reconcile the wave theory and the particle theory of light by means of the new ideas of quantum mechanics. Today we are collecting evidence on possible health risks from microwaves used in mobile phone networks. The cheapness and popularity of mobile phones may make the public and manufacturers reluctant to accept adverse findings, even if risks are made widely known in the press and on television. Although scientists can provide evidence and evaluation of that evidence, there may still be room for controversy and a reluctance to accept scientific findings, particularly if there are vested social or economic interests to contend with. This is most clearly shown today in the issue of global warming.