2. The first great change in scientific outlook was made by Nicolaus Copernicus (1473 -1543). He disproved the Ptolemaic system or Geocentric theory, which stated that ‘the earth was the centre of the universe and all other heavenly bodies move round it in circles’. To Copernicus, the sun was the centre of the universe while the earth and other heavenly bodies move round it, in a uniform circular motion. This view is called the Copernican world system or Heliocentric theory.
3. Copernicus got into trouble with the church authorities who believed the Geocentric theory. But it did not make him give up his theory.
4 The next person that brought this change in scientific outlook was Galileo (1564 -1642). While Copernicus obtained his result by using simple observations and mathematics, Galileo added experiments to those two. He invented a scientific instrument of observation called the telescope. This instrument enabled him to extend his sense of sight and he saw clearly that the sun was at the centre of the universe. Thus confirming the theory of Copernicus. Galileo is thus called the discoverer of the true research method of the physical sciences.
5. Johannes Kepler (1571 -1630) discovered the laws that govern movements of the heavenly bodies. He was the first person to apply mathematics as an empirical instrument to discover these laws.
6. However, in spite of their results, Galileo and Kepler could not answer why objects do not fly off the earth, considering their submissions that the earth revolves or moves round the sun. Another question they couldn’t answer was how it was possible for the earth, which was suspended in empty space to go round the sun without anything pushing it.
7. It was in the year Newton 1660 that these questions were answered by Isaac (1642 - 1727 AD. He proposed a theory of gravitational attraction to answer these questions. Gravitation is the force that pulls every object in the universe towards ever y other object in the universe. Therefore, the earth pulls every object within it towards its centre so that’s the reason they don’t fly off the earth when it moves round the sun. The sun also has a centre of gravitation, which pulls the earth, and all other heavenly bodies round it.
8. Francis Bacon (1561 - 1626) was the first person who attempted to arrange the steps of the scientific method in a logical manner.
9. The classic ages of science were the 18th and 19th centuries. An explosion in growth of knowledge of nature occurred at this time, especially in the 19th century
10 The explosion in Chemistry was started by Antoine Laurent Lavoisier (1743 - 1794). He discovered that it was a gas, which he called oxygen that enables combustion and respiration to take place. He also introduced the gravimetric method of carrying out research in Chemistry.
11. In the 19th centur y, there was a common understanding that atoms and molecules were the basic building blocks of matter, and that cells are the basic building blocks of living things. This statement led to the formulation by Shwann and Matthias Schleiden in of the cell theory 1839. The cell theory is one of the fundamentaltheories of Biology.
12. Another fundamental theory of Biology is the theory of evolution by natural selection. It was proposed by Charles Darwin in 1859
