91download.com supports a wide range of platforms, including YouTube, Facebook, Twitter, TikTok, Instagram, Dailymotion, Reddit, Bilibili, Douyin, Xiaohongshu and Zhihu, etc. Click the download button below to parse and download the current video
Have you ever made a discovery that turned out to be right for all the wrong reasons? Such was the case for two German scientists over a century ago, when they stumbled upon a pivotal insight in quantum physics despite their own skepticism. This is the tale of the Stern-Gerlach Experiment, a story of unexpected science, serendipity, and a man who inadvertently confirmed quantum theory while believing it to be fallacy.
Otto Stern, a former postdoc of Albert Einstein, was a Doubting Thomas when it came to quantum theory. In 1913, he was so convinced of its flaws that he threatened to abandon physics if it proved to be true. Yet, destiny had other plans. Stern's experiment, designed to disprove Niels Bohr's quantum model of the atom, inadvertently became one of the most significant experiments in quantum physics history.
Bohr's model proposed that electrons orbit the nucleus in specific, discrete paths, each with a fixed amount of angular momentum. This was a departure from classical physics, which suggested electrons could orbit at any orientation. Stern set out to prove this quantum theory wrong by firing a beam of silver atoms through a magnetic field and observing their deflection on a photographic plate.
According to classical theory, the electrons would be deflected randomly, creating a continuous stripe. However, if Bohr was correct, the electrons would display discrete angular momentum, resulting in two distinct blobs on the plate. Stern's choice of silver atoms was strategic; they would leave a clear mark and only one electron in the outer shell would interact with the magnetic field.
Enter Walther Gerlach, Stern's experimental counterpart, who built and operated the apparatus. Despite the challenges, including the financial constraints of post-World-War-One Germany, they persisted. And on February 7th, 1922, Gerlach observed the two separated blobs, confirming Bohr's model. Or so they thought.
The physics community was overjoyed, heralding the Stern-Gerlach Experiment as a triumph of quantum theory. But the story took a twist. A few years later, it was realized that the silver electron's angular momentum should have been zero, according to new calculations. The experiment should have shown one big blob, not two. Instead, Stern and Gerlach had uncovered an intrinsic angular momentum, which we now know as spin.
This spin was not part of Bohr's model but was a new quantum property. And while Stern and Gerlach were incorrect in their predictions, their experimental blunders, including Gerlach's love for cheap cigars, which helped make the silver deposits visible, led to a discovery that shaped modern physics.
The Stern-Gerlach Experiment is a reminder that science is often a serendipitous journey. It's a story of how two scientists, working with the wrong assumptions, accidentally confirmed a fundamental aspect of quantum physics. Today, we recognize the Stern-Gerlach Experiment as a cornerstone in our understanding of quantum mechanics, proving that sometimes, being wrong can lead to the most profound insights.
So, what can we learn from Stern and Gerlach's unexpected journey? That in the pursuit of knowledge, even our mistakes can be a part of the greater truth. And that's a story worth telling.
Share on Twitter Share on Facebook