In the realm of quantum physics, many regard the double slit experiment as “the most beautiful experiment” majorly due to the nature of observation. This experiment toys with the unlearned beliefs of reality; most of us assume the present and the tangible is our reality. However, the double slit experiment slashes aside these beliefs and attempts to demonstrate that when a system is being observed – such as single light particles (photons) – it behaves differently (or in a different reality) than when we are not observing it.
In the video we see how the photons are beamed through two slits and ultimately create a wave trajectory while traveling:
If we are observing: Each photon travels through only one of the slits
If we are not observing: The photons seem to pass through both slits at once in the shape of a “connected” wave
This situation requires us to consider two forms of reality. As a quantum system, many physicists suggest we can only eliminate the reality of the photons existing in space and time until we actually observe it. Basically, we selectively control when it exists, but this is obviously not an “ideal” solution.