The double-slit experiment is a famous experiment in quantum physics that demonstrates the wave-particle duality of matter and the fundamental probabilistic nature of quantum mechanics. In its simplest form, the experiment involves firing particles, such as electrons or photons, through a barrier with two slits and observing the resulting interference pattern on a screen behind the barrier.
The size of the object that can exhibit wave-like behavior and produce an interference pattern in the double-slit experiment depends on its de Broglie wavelength. The de Broglie wavelength is given by the equation λ = h / p, where λ is the wavelength, h is Planck's constant, and p is the momentum of the object.
For macroscopic objects, such as everyday objects like baseballs, people, or even larger structures, the de Broglie wavelength is incredibly small due to their large mass and momentum. Consequently, the wavelength is so tiny that any wave-like behavior and interference effects become effectively negligible, making it practically impossible to observe the double-slit interference pattern with such objects.
Quantum effects are most pronounced at the microscopic scale, where particles like electrons and photons exhibit both particle and wave-like properties. These particles have extremely small masses and momenta, resulting in measurable de Broglie wavelengths. Thus, the double-slit experiment has been successfully conducted with particles like electrons, photons, and other subatomic particles.
In summary, while the double-slit experiment demonstrates wave-particle duality for particles at the quantum scale, macroscopic objects are too massive to exhibit similar wave-like behavior and produce interference patterns.