Yes, Thomas Young, an English scientist, did observe the interference patterns produced by waves passing through double slits. In the early 1800s, Young conducted a famous experiment known as Young's double-slit experiment, which provided evidence for the wave nature of light.
In Young's experiment, he shone light through a barrier with two closely spaced slits, allowing the light to pass through and strike a screen. When the light passed through the slits, it diffracted and created overlapping wavefronts that interfered with each other. The interference resulted in a pattern of alternating bright and dark fringes on the screen.
This phenomenon demonstrated the wave-like behavior of light, as the interference pattern could be explained by the superposition of waves from the two slits. Young's experiment played a significant role in supporting the wave theory of light, which was in contrast to the prevailing particle theory proposed by Isaac Newton.
Later developments in physics, such as the discovery of the photoelectric effect and the formulation of quantum mechanics, revealed that light also exhibits particle-like behavior, known as the dual nature of light. However, Young's double-slit experiment remains a fundamental demonstration of wave interference and an important milestone in the understanding of light.