Quantum phenomena refer to the strange behaviors and properties of particles at the atomic and subatomic levels. These behaviors often defy classical physics, leading to concepts like superposition, where particles can exist in multiple states at once, and entanglement, where particles become interconnected regardless of distance. One of the most famous examples of quantum phenomena is the double-slit experiment, which demonstrates how particles like electrons can display both wave-like and particle-like properties. This experiment highlights the fundamental uncertainty in measuring quantum states, a principle encapsulated in Heisenberg's uncertainty principle.