Studying physics can be likened to Carpentry where using the right type of tool makes the job less tedious. The invention of quantum mechanics during the first 27 years of the twentieth century marked a revolutionary change in our understanding of phenomena on microscopic scales. Classical physics ideas held before then had instant limitations in their validity, as quantum mechanics became an alternative theory more richer both in scope and application.

This course unit is one of the core units in the third year Bsc astronomy and astrophysics degree at the University of Nairobi. It addresses the important astrophysical subject of stellar evolution which describes how the observed physical properties of stars change during their lifetime- from birth to death.