The double-slit experiment is a classic experiment in quantum mechanics that demonstrates the wave-particle duality of particles, such as electrons or photons. While the interpretation and understanding of the experiment can be complex, there isn't necessarily a single "overlooked obvious answer" that would drastically simplify its understanding.
However, one commonly misunderstood aspect of the double-slit experiment is the role of observation or measurement. The behavior of particles in the experiment can change depending on whether or not they are observed or measured during their journey through the slits and towards the screen.
When the experiment is conducted without any measurement or observation, particles (e.g., electrons or photons) display wave-like behavior, resulting in an interference pattern on the screen behind the slits. This suggests that the particles exhibit wave-like characteristics and can interfere with themselves.
However, when an attempt is made to determine through which slit a particle passes by introducing a measurement or observation, the interference pattern disappears, and the particles behave more like individual particles, creating a pattern of two distinct bands on the screen.
The act of measurement or observation disturbs the delicate quantum state of the particles, collapsing the wavefunction and forcing the particles to behave more like classical particles with definite positions. This phenomenon is known as "the collapse of the wavefunction."
The interpretation and implications of the double-slit experiment continue to be subjects of debate and ongoing research in the field of quantum mechanics. While there are various interpretations, such as the Copenhagen interpretation or the many-worlds interpretation, there isn't a single overlooked answer that drastically simplifies the understanding of the experiment. It remains a complex and fascinating demonstration of the wave-particle duality and the role of measurement in quantum systems.