Physics for O.N.C. Courses is a textbook that aims to serve the specific needs of science and engineering students at Ordinary National Certificate (ONC) level in physics. Topics covered range from surface tension and viscosity to gas laws and the specific heats of gases, sources of sound and sound waves, and spherical mirrors. Lenses, the eye, refraction at plane surfaces, and dispersion of light are also discussed. This book is comprised of 27 chapters and opens with a review of some basic principles and concepts in physics such as mass, force, and weight; work, energy, and power; states of matter; density and specific gravity; and pressure and diffusion. The reader is then introduced to surface tension, viscosity, the nature of heat, and elementary thermometry. Thermal expansion, heat quantity and its measurement, and properties of gases are also discussed, along with thermal radiation and wave motion. The remaining chapters focus on vapors and vapor pressure; thermal conductivity; vibrations of strings and rods; frequency and velocity of sound; sound intensity and the Doppler effect; and elementary principles of geometric optics. The final chapter is devoted to the fundamentals of atomic and radiation physics. This monograph will be a valuable resource for physicists, physics teachers, and science and engineering students at ONC level in physics.