Investigations in Natural Science is a program in secondary school biology, chemistry, and physics based upon the description of science as a quest for knowledge, not the knowledge itself. This student manual contains the 36 physics investigations which focus on concepts related to: movement; vectors; falling objects; force and acceleration; a property of matter; mass and acceleration; laws of motion; circular motion; gravitational attraction; friction; the balance; the NBP (natural balance point); multiple forces; the lever; other machines; the inclined plane; energy; measuring heat; measuring heat in solids; circuits and currents; electrical circuits; electricity at rest; magnetism; currents and magnetism; light; light and plane mirrors; light and concave mirrors; refraction of light; light and converging lenses; waves; waves and barriers; speed of a wave; meeting waves; periodic wave relationships; sound; and harmonics. Each investigation (which is accompanied by one or more readings with questions to answer) includes activities related to the three learning cycle components, namely, exploration, conceptual invention (the idea), and expansion of the idea. (JN)