Physical phenomena
Observable events or processes in the material world, governed by physical laws. They include changes in matter, energy, motion, and fields.
Matter: Substance with mass and volume, composed of particles and fields. Physical events often involve matter changing state, position, or composition.
Classical mechanics: The theory describing motion and forces at everyday speeds and scales. It accounts for familiar phenomena such as falling, collisions, and orbital motion.
Lightning: A sudden electrical discharge within a cloud, between clouds, or between cloud and ground. It makes atmospheric charge separation visible as light, heat, and sound.
Biological phenomenon: An observable process or event in living organisms or biological systems. Biological events involve physical processes but are also organized by living systems.
Chaos theory: The study of deterministic systems whose outcomes depend sensitively on initial conditions. Chaotic systems obey physical laws yet can resist long-term prediction.
Energy: A conserved physical quantity transferred between systems or converted among forms. Energy transfer and transformation underlie many observable processes.
Electromagnetism: The physical interaction involving electric charge, electric fields, and magnetic fields. It explains light, electrical effects, magnetism, and many material interactions.
Superconductivity: A state in which a material has zero electrical resistance and expels magnetic fields below a critical temperature. It is a striking material behavior with consequences for magnets and electrical technology.
Chemical phenomenon: An observable change involving the rearrangement of atoms or molecules through chemical reactions. Chemical changes are physical events distinguished by changes in molecular composition.
Emergence: The appearance of system-level patterns or properties not evident in isolated components. It raises questions about how collective phenomena relate to underlying physical laws.