The Double-Slit Experiment: Proof of Quantum Weirdness

The double-slit experiment shines light or particles through two narrow openings onto a screen.
When no one observes, waves form an interference pattern—bright and dark stripes.
Surprisingly, even single particles, like electrons, build the same wave pattern over time.
But when observed, particles act like tiny bullets, creating two neat bands instead.
This shows that observation changes how quantum objects behave.
The experiment reveals light and matter have both wave and particle properties.
It challenges the idea of reality being fixed until measured.
Even molecules much larger than electrons have shown the same strange effect.
The experiment is often called “the most beautiful proof of quantum mechanics.”
It demonstrates that the act of measuring shapes the very outcome of reality.