The double-slit experiment is a classic experiment in physics that demonstrates the wave-particle duality of matter and light. It shows that particles, such as electrons or photons, can exhibit both wave-like and particle-like properties.
In its simplest form, the double-slit experiment involves a barrier with two narrow slits and a screen placed behind it. When light or particles are directed toward the barrier, they can pass through the slits and create an interference pattern on the screen. If particles were purely particles, one would expect to observe two distinct bands corresponding to the slits. However, the experiment reveals an interference pattern, similar to what is observed when waves interact.
This phenomenon suggests that particles, such as electrons or photons, can exhibit wave-like behavior, characterized by interference patterns. The experiment's outcome depends on whether the particles are observed or not. When the experiment is set up to detect which slit a particle goes through, the interference pattern disappears, and the particles behave more like individual particles, showing localized impacts on the screen.
Regarding your second question, the double-slit experiment has indeed been performed with atoms. While atoms are more massive than electrons or photons, they also exhibit wave-particle duality. Experiments using atoms in the double-slit setup have been conducted successfully. These experiments involve cooling atoms to extremely low temperatures to minimize their interactions and ensure they behave more like waves.
The double-slit experiment with atoms provides further evidence of the wave-particle duality of matter. It demonstrates that not only subatomic particles like electrons and photons but also larger particles like atoms can exhibit wave-like behavior and interfere with themselves. This experiment highlights the fundamental principles of quantum mechanics and challenges our classical intuitions about the nature of particles and waves.