Wave particle duality that all particles exhibit both wave and particle properties. A central concept of quantum mechanics, this duality addresses the failure of classical concepts like particle and wave to fully describe the behaviour of quantum-scale objects. The idea of duality originated in a debate over the nature of light and matter that dates back to the 17th century, when Christiaan Huygens and Isaac Newton proposed opposing theories of light, one theory was that light consisted of waves and the other theory was that light consisted of particles. These two theories were both valid and supported by scientists that developed a further understanding of light. Due to Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr, and many others, the current theory is that particles act like waves and waves act like particles.
The double slit experiment is one of the most famous and recognisable experiments in quantum mechanics, the experiment consists of a beam of particles such as electrons. These electrons travel through a double slit and then hit a screen behind where the arrival of each electron is recorded at a specific point on the screen. But while each electron arrives like a particle, many electrons together create an interference pattern that can only be explained if the electrons also behave like waves. What makes this even stranger is the prediction that the same effect ought to be measurable for much larger objects