How does electron diffraction illustrate the Heisenberg uncertainty principle?

Electron diffraction illustrates the Heisenberg uncertainty principle by demonstrating the fundamental trade-off between measuring a particle's position and its momentum.1

When a stream of electrons passes through a narrow slit, the wave-particle duality of the electron causes it to spread out, a phenomenon known as diffraction. If the slit width ($b$) is reduced to pinpoint the electron's position more precisely, the diffraction pattern widens, increasing the uncertainty in the electron's direction and, consequently, its momentum component ($p_x$).1

Specifically, the uncertainty in position ($\Delta x$) is related to the slit width, while the uncertainty in momentum ($\Delta p_x$) arises from the spread of the diffracted beam. According to the de Broglie formula, the product of these uncertainties is of the order of Planck's constant ($\hslash$), confirming that increasing the precision of one measurement inherently decreases the precision of the other. This experiment highlights that at the atomic scale, the act of measurement is inseparable from the properties of the system being observed.12