Physics is the fundamental science that seeks to understand how the universe works. It studies matter, energy, motion, forces, space, and time through careful observation, controlled experimentation, and mathematical modeling. From the smallest particles to the largest galaxies, physics provides the foundation for understanding natural phenomena.
Physics is divided into several major branches, each focusing on different aspects of the natural world. Classical mechanics studies motion and forces. Thermodynamics deals with heat and energy transfer. Electromagnetism explores electric and magnetic fields. Quantum mechanics examines the behavior of atoms and subatomic particles. Relativity theory describes space, time, and gravity. Optics investigates light and electromagnetic radiation.
Newton's three laws of motion form the foundation of classical mechanics. The first law, also known as the law of inertia, states that objects resist changes in their motion. The second law quantifies the relationship between force, mass, and acceleration with the famous equation F equals m a. The third law explains that forces always come in pairs - when you push on something, it pushes back with equal force in the opposite direction.
Energy is the fundamental capacity to do work and exists in many forms. Kinetic energy is the energy of motion, while potential energy is stored energy due to position or configuration. The pendulum demonstrates energy transformation - at the highest points, potential energy is maximum and kinetic energy is minimum. At the bottom, kinetic energy peaks while potential energy is lowest. The law of conservation of energy tells us that the total energy remains constant as it transforms between different types.