At the atomic level, nature behaves in ways that defy everyday intuition.

These particles interact through four fundamental forces: Gravity , Electromagnetism , the Strong Nuclear Force (which holds nuclei together), and the Weak Nuclear Force (responsible for radioactive decay). 4. Wave-Function and Probability

Proposed by Werner Heisenberg, this principle states that it is impossible to know both the exact position and the exact momentum of a particle simultaneously. The more precisely we measure one, the less precisely we know the other. 2. Relativity: The Physics of High Speeds and Gravity

Objects like electrons and photons exhibit properties of both particles and waves. They are neither one nor the other exclusively, but a "quantum" entity that behaves differently depending on how it is measured.

Unlike the deterministic nature of classical physics, modern physics is built on . The state of a particle is described by a mathematical "wave-function." Until an observation is made, a particle exists in a superposition of multiple states at once.

Introduction to Modern Physics Modern physics is the study of the underlying principles that govern the universe at its most extreme scales—from the subatomic to the cosmological. Emerging at the dawn of the 20th century, it moved beyond the certainties of "Classical Physics" (Newtonian mechanics and Maxwell’s electromagnetism) to address phenomena that the old laws could not explain. 1. Quantum Mechanics: The Physics of the Very Small

Modern physics seeks to categorize all known subatomic particles and the forces that govern them.