The double-slit experiment: Is light a wave or a particle?

The double-slit experiment is one of the most famous experiments in physics and definitely one of the weirdest. It demonstrates that matter and energy (such as light) can exhibit both wave and particle characteristics — known as the particle-wave duality of matter — depending on the scenario, according to the scientific communication site Interesting Engineering.

According to the University of Sussex, American physicist Richard Feynman referred to this paradox as the central mystery of quantum mechanics.