In the double-slit experiment, both uncertainty and diffraction play a role in causing the spread of the wave pattern observed after passing through the slits. Let's explore each of these factors:
Diffraction: When a wave, such as light or matter, passes through a narrow slit, it undergoes diffraction. Diffraction is a phenomenon where the wave spreads out and bends around obstacles or through narrow openings. In the double-slit experiment, the wave nature of particles, such as electrons or photons, causes diffraction as they pass through the slits. This diffraction leads to the interference pattern observed on the screen, with regions of constructive and destructive interference.
Uncertainty Principle: The uncertainty principle, a fundamental principle in quantum mechanics, states that certain pairs of physical properties, such as position and momentum, cannot be precisely determined simultaneously. In the context of the double-slit experiment, the uncertainty principle plays a role in determining the momentum and position of the particles passing through the slits. The uncertainty in the momentum of the particles leads to a spread in their possible trajectories, contributing to the widening of the interference pattern on the screen.
It's important to note that the spread of the wave pattern in the double-slit experiment is a consequence of the wave-like behavior of particles and the underlying principles of quantum mechanics. Both diffraction and the uncertainty principle are involved in explaining the observed behavior, and they are interconnected phenomena rather than separate causes.