Physics Class 11 Chapter 1. Physical World | Page 2

Science and its origin
Science is a systematic understanding of natural phenomena in detail so that it can be predicted , controlled and modified . Science involves exploring , experimenting and speculating phenomena happening around us . o The word Science is derived from a latin verb Scientiameaning ‘ to know ’. o Scientific method is a way to gain knowledge in a systematic and indepth way . It involves : o Systematic observations o Controlled experiments o Qualitative and Quantitative reasoning o Mathematical modeling o Prediction and verification ( or falsification ) of theories o Speculation or Prediction
o Science does not have any final theory . The improved observations , accurate tools keep improving the knowledge and perspective . Johannes Kepler used Tycho Brahe ’ s research on planetary motion to improve Nicolas Copernicus theory .
o Quantum mechanics was developed to deal with atomic and nuclear phenomena . Work of Ernest Rutherford on nuclear model of atom became basis of quantum theory given by Niels Bohr . Antiparticle theory of Paul Dirac led to the discovery of antielectron ( positron ) by Carl Anderson .