By far, one of the most thought-provoking experiments in the history of science is the double slit experiment. The double slit experiment reveals a mysterious behavior of Nature, the strange duality between particles and waves. Beyond just plain physics, it touches one of the most fundamental questions of metaphysics, what is matter?
Much was written about the double slit experiment, and it would be easy to write much more. But for the time being, I won't write about this experiment myself. Instead, I will let Dr. Quantum introduce this fascinating experiment to you.
Although many consider this experiment to be described well by quantum theory, I believe the double slit experiment still holds the key to a better understanding of Nature.