The Experiment That Confirmed Entanglement
The double slit experiment was a monumental experiment performed by Thomas Young that helped scientists understand the behavior of small particles.
The experiment was conducted by firing a beam of photons through two narrow slits and behind them was a solid wall. Instead of creating two strips of light on the wall as one would expect, a striped pattern formed, with the brightest strip directly between the two slits. This could only be explained by light acting as a wave, which would cause this “interference pattern.”
During the experiment, they shot one particle at a time through toward the slits. Oddly enough, the interference pattern still remained. This suggested that the particle went through not one, but both slits simultaneously and interacted with itself, creating the wave-like pattern.
Even stranger, they attempted to detect which slit the photons when through with each shot, and then only two stripes were created. This was an astounding realization. The simple act of measuring caused the light to begin acting as a particle, and not a wave.
This discovery confirmed the existence of entangled particles. The act of measuring made the photon decide with its entangled pair which slit it would go through.