In the waning hours of 2024 and the opening moments of 2025, Charles Zhang, founder and CEO of Sohu, once again transformed his classroom podium into a stage for an immersive physics lecture. Broadcasting live, Zhang marked the new year alongside program representatives and a wide digital audience.
For over three hours, Zhang navigated intricate topics, from the quantum mechanics embedded in daily life to Carl Sagan’s iconic “Pale Blue Dot” photograph captured by Voyager in 1990. Equipped only with chalk and five blackboards, he derived the fundamentals of chemical bonds and matter’s structure through rigorous mathematical formulas—no teleprompter or handouts in sight.
Unlike other entrepreneurs who prefer casual reflections or speculative forecasts in their year-end broadcasts, Zhang stayed true to his pedagogical rigor. Notably, his choice of quantum mechanics as a theme was finalized just weeks prior, with only a few days allocated for preparation. This efficiency reflects his years of teaching experience—over 230 sessions in around three years—and a lifelong passion for physics. Through his lectures, Zhang embodies a philosophy of continuous learning, one that resonates with an ever-growing online audience.
Demystifying quantum mechanics in three hours
“Quantum mechanics might seem mysterious, but it’s actually present in our everyday lives,” Zhang began his lecture. Over the next three hours, he linked complex theories to relatable daily phenomena, illustrating the relevance of quantum mechanics in modern life.
For instance, the first ray of sunlight seen upon waking in the morning has traveled 8 minutes and 20 seconds at the speed of light to reach Earth. Using Wien’s formula, Zhang explained that the peak energy of solar radiation falls within the frequency range perceivable by the human eye, which determines the limits of human vision.
As morning sunlight streams in, powering an electric toothbrush requires lithium-ion batteries. Lithium’s single outer electron allows it to easily release electrons, enabling efficient energy transfer and powering various devices.
Following this logic, Zhang continued analyzing modern life through the lens of quantum mechanics: electric vehicles for commuting, bright streetlights during dark hours, breakfast cafe purchases, and the computer screens stared at in offices. All these scenes were deconstructed into the microcosm of quantum mechanics.
Returning home at night, Zhang offered practical advice based on quantum principles: wash clothes promptly to prevent stains from diffusing into fabric, and ventilate homes to reduce radon gas, which emits alpha particles through quantum tunneling, thereby lowering the risk of lung cancer.
Compared to his previous New Year lecture, where Zhang spent four hours delving into general relativity and the nature of time, the latest session’s structure followed a more relatable approach by aligning with everyday activities. While the lecture remained intellectually stimulating with rigorous derivations, it also included accessible anecdotes for non-experts.
Throughout 2024, Zhang’s physics class frequently covered quantum mechanics. The third volume of his series on the subject was published, with Zhang writing in its preface: “Enjoy learning and calculating.” This New Year’s lecture both echoes the past year’s broadcasts and embodies this philosophy.
Sohu’s knowledge-driven renaissance
Since its debut on November 5, 2021, Zhang’s physics class has evolved into a fixture of online education, with over 230 sessions delivered across more than three years. Offering weekly updates ranging from live streams to short videos, both online and offline, Charles Zhang’s transformation into a “physics teacher” has transcended its origins as a fleeting trend to become a symbol of knowledge-sharing in the digital era.
Speculation has swirled around Zhang’s dual pursuits, with some suggesting he has abandoned his business responsibilities to focus on physics. However, his recent endeavors—spanning live broadcasts, interviews, and more—are intrinsically tied to Sohu’s strategic shift toward knowledge-based streaming initiatives.
The physics class officially launched in late 2021, aligning with Sohu Video’s broader transition into a knowledge-driven platform. Even before this, Sohu Video had started building a foundation with expert-led streams on topics like culture, automotive technology, and legal insights. Zhang’s remarks at various events reflect Sohu’s commitment to redefining its media and social platform strategy.
By doubling down on media and educational initiatives, Sohu has leveraged Zhang’s dedicated fanbase as a potent promotional asset. This synergy—between Zhang’s intellectual pursuits and Sohu’s business objectives—creates a unique advantage for the company.
Much of Zhang’s lecture material, including the framework for his recent New Year live stream, is drawn directly from his daily experiences. Whether inspired by a fleeting thought during his commute or reflections from a business meeting, Zhang integrates these moments into his lectures, seamlessly balancing his role as Sohu’s CEO with his passion for physics. Today, Zhang’s physics class stands as a marquee intellectual property under the Sohu Video banner.
This year’s New Year lecture, for example, attracted over 10 million viewers. Across his more than 230 sessions, Zhang has cultivated a distinct style of teaching—one that bridges the rigor of academia with the accessibility of modern digital platforms, offering an experience far removed from traditional classrooms or standard science videos.
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Sharing knowledge through social networks
Adopting a scholarly approach may not create viral sensations overnight, but fostering public interest in science and lifelong learning through interactive formats has the potential to leave a profound and lasting social impact.
Zhang’s physics class exemplifies this shift. A search for physics topics on Chinese social media or search engines increasingly yields detailed derivations and in-depth discussions— a stark contrast to the superficial, astrology-like content that once dominated these platforms.
During the latter half of his latest lecture, Zhang dedicated nearly an hour to deriving the origins of chemical bonds across five blackboards. He explained how the world is no longer conceptualized in terms of earth, wood, fire, metal, and water, but rather through the lens of elements, molecules, proteins, DNA, and even the intricate structure of the human brain— all phenomena rooted in the principles of quantum mechanics.
By sparking curiosity and championing logical deduction, Zhang nurtures analytical thinking and effective study habits in his audience. The benefits of his teaching extend far beyond academics, enhancing professional productivity and promoting rational, well-informed decision-making.
Eschewing trend predictions and motivational cliches, Zhang’s focus remained practical and empowering. He aimed to equip his viewers with reasoning tools and habits they could apply throughout 2025. During his latest lecture, Zhang offered a New Year wish that reflected his ethos: “Stay active, eat healthily, remain fit, and strive for progress and achievements in 2025.”
KrASIA Connection features translated and adapted content that was originally published by 36Kr. This article was written by 36Kr Caijing.