Free online courseModern Physics

Course Description

Modern physics is where familiar ideas from everyday motion meet the surprising rules that govern light, atoms, and the structure of space and time. This free online course is designed to help you cross that bridge with confidence, turning topics that often feel abstract into clear, usable concepts. If you are studying physics at school, preparing for exams, or simply curious about how the universe works beyond Newton, you will gain a stronger foundation for the twentieth-century revolution in science.

You will explore why late-1800s experiments created problems that classical mechanics and traditional electromagnetism could not solve, and how those gaps pushed physics toward new frameworks. Along the way, you will build an intuition for how modern physics reshapes core assumptions: what it means for measurements to depend on the observer, why time is not treated as universal in the same way as in classical models, and how Einstein’s special relativity changes the relationship between space, time, and motion.

A central theme is the nature of light. You will examine what modern physics says about light’s behavior, how its description connects to both wave-like and particle-like perspectives, and why that duality became a major turning point in scientific thinking. You will also connect these ideas to one of the most important constants in science: the speed of light, and the modern principle that it behaves in a consistent way that challenges common sense but aligns with experimental evidence.

To reinforce understanding, the course includes exercises that prompt you to reason through key questions rather than just memorize statements. By the end, you should be able to explain the major motivation for quantum ideas, describe the modern view of space and time, and interpret what modern physics implies about light and its speed in a clear, exam-ready way.