The wave-particle duality of electrons, as well as other quantum particles, can be demonstrated through the double-slit experiment. The experiment shows that particles such as electrons exhibit both wave-like and particle-like behavior.
In the double-slit experiment, a beam of electrons is directed towards a barrier with two narrow slits. Behind the barrier, a screen or detector is placed to observe the pattern formed by the electrons that pass through the slits.
When the intensity of the electron beam is low, and one electron is sent at a time, an interference pattern emerges on the screen. This pattern consists of alternating bands of dark and light regions, similar to the pattern observed in the classical interference of light waves.
This interference pattern indicates that the electrons have exhibited wave-like behavior. Waves can interfere constructively (creating bright regions) or destructively (creating dark regions) when they overlap. The observed interference pattern suggests that the electrons passing through the slits interfere with themselves, much like waves do, and create an interference pattern on the screen.
However, when a detector is placed near the slits to determine which slit each electron passes through, the interference pattern disappears. The electrons now behave more like particles, and their distribution on the screen resembles the pattern expected for individual particles passing through the slits.
This observation highlights the wave-particle duality of electrons. When unobserved, electrons behave as waves and exhibit interference patterns, indicating their wave-like nature. But when measured or observed, their behavior collapses into that of particles, with definite paths and no interference pattern.
The double-slit experiment, originally conducted with light by Thomas Young in the early 19th century, has been replicated with various particles, including electrons, confirming the wave-particle duality at the quantum level. This experiment played a significant role in shaping our understanding of quantum mechanics and the inherent dual nature of particles.