The double-slit experiment, is a demonstration that matter and energy can display characteristics of both waves and particles. The basic concept of this experiment is very common to the scientist . If we send particles through one slit, we will get a line on the detector. If we use two slits and then fire the particles, we will get two lines on the detector. But what will happen if we send wave instead ? The answer is simple, we will find interference patterns on the detector.
Now lets jump to the quantum world, and fire electrons through the slit. You know electron is a small particle too.
Lets fire it through a single slit. What will happen? We will find a single line on the detector (as expected).
Now lets fire it through two slits. What will happen now? Shall we get two lines on the detector (as we saw for the particles in classical world)?
Amazingly we won’t. Instead we will have a interference patterns. How does this happen? It happens because in the quantum world the electron behalves like both particles and waves. This phenomenon brought us to a new era” The wave-particle duality ” . I found a nice animation about this double-slit experiment on youtube. Shared it with the article. Hope it will help you to understand more easily. ENJOY! 😀