An olive green tool vest is a staple in the wardrobe of Wu Yuren, a retired professor of physics from Shanghai's Tongji University. Its many patch pockets are like magic boxes from which Wu pulls gadgets when conducting lab experiments. At times, she almost resembles a magician pulling a rabbit out of a hat.

A slim figure with silver locks and a lively temperament, Wu likes to move around and use her hands when explaining the experiments she conducts in her videos. With over 4 million followers on major short video platform Douyin, China's TikTok, the 74-year-old has shared more than 400 such videos, earning her the nickname "science grandma."

Most of these videos are under two minutes long and use simple and interesting experiments to illustrate abstract and difficult physics concepts. This is Wu's new career path after having taught in a classroom for some 50 years.

Science for all 

The lab is located at a science base in Shanghai. In 2018, Wu set up a club together with some other retired physics professors and graduates holding a physics Ph.D., aiming to pique the real interest of younger generations in a casual, inspiring and fun manner.

With a team of more than 10, the club started out by organizing public classes in local communities and in 2020 began creating short videos starring Wu as she conducted lab experiments. The quirky science videos soon became an online sensation.

The tools she uses in the experiments are garden-variety objects. For example, she once used a cooking pot to introduce China's Five-hundred-meter Aperture Spherical Radio Telescope; she blew up a balloon to explain rocket launches and used a broom to illustrate how the energy of cosmic rays in space gradually weakens and disperses.

"My interest in physics mainly came from my father, a space scientist, and it just never faded," Wu said during a 2021 interview with China Central Television (CCTV). "Many regard physics as something highly difficult to understand. Through my experiments, I want to show that this is not the case. It can be found everywhere in our daily lives and everybody can understand," she explained.

Short video sharing platforms have expanded her classroom from one confined within four walls to cyberspace—a place accessible to almost all.

On March 4, CCTV played a snippet of one of her videos as part of the introductory video of 13 retired scholars at the annual Touching China award ceremony, an event honoring those whose actions have made them inspiring role models over the previous year. The scholars, referred to as "silver hair knowledge hosts," included academicians, professors, primary and middle school teachers. With an average age of 77, they share their knowledge of astronomy, physics, literature, aesthetics and other topics across Chinese short video or live-streaming platforms.

"The digital divide, or the tendency that older adults are less adept at using and hence less likely to use the Internet than younger people, doesn't apply at all to these senior scholars," one netizen commented. "They are more diligent in updating their videos than many of their younger peers. I believe it is their passion for popularizing knowledge that has become their greatest motivator."

According to the 51st Statistical Report on China's Internet Development released by China Internet Network Information Center on March 2, as of December 2022, the number of short video users in China exceeded 1 billion, a record high.

On Douyin alone, the number of "knowledge content" releases increased 35.4 percent year on year in 2022. The platform verified 400 professors last year, and 45 academicians and four Nobel Prize winners used it to share their scientific theories and research results.

Age is just a number 

Wang Pinxian, an 87-year-old academician with the Beijing-based Chinese Academy of Sciences as well as a retired professor from Tongji University, was among the 13 scholars honored by CCTV as role models. As one of China's leading deep-sea scientists, he has attained cyberstar status in recent years for his science popularization videos. He has over 1.7 million followers on Bilibili, a popular video-sharing platform mainly targeting Gen Zs.

Wang usually uploads videos that run 7 to 8 minutes. They feature him sitting and talking about a range of topics and questions, e.g., "Earth rotates at the speed of over 1,600 km an hour at the equator, why we don't feel dizzy going round and round at this speed?" or "what do deep-sea gardens look like?"

In 2018, at the age of 82, he boarded China's manned Deep Sea Warrior submersible and dove to a depth of 1,400 meters in the South China Sea. It was his third time plunging into the dark depths. "I felt like Alice in Wonderland—with the wonderland being the deep sea," he said in the related video, describing every detail of the deep sea coral garden views and the sea creatures he spotted.

His work of popularizing science for kids and teenagers started in 2011 while recording the marine volume of the audiobook series One Hundred Thousand Whys, a popular science series mainly for children. In 2020, he started creating short videos popularizing deep sea science and uploaded them to Bilibili, making him the first ever academician to do so. In October 2020, he published his book Deep Sea in Simple Words, which later became a bestseller.

"Time is very precious for people my age," Wang said during a November 2022 interview with National Science Review, an English-language peer-reviewed multidisciplinary open-access scientific journal published by Oxford University Press. "I plan to publish another popular science book by the time I turn 90."

But it's not just professors from top-ranking universities foraying into cyberteaching.

Wang Guangjie, 82, is a retired teacher of electrical engineering and circuitry from a vocational high school in Jining, Shandong Province. He is now the very active host of his own live-streamed class on Douyin, from 7:30 to 9 p.m., Monday to Friday.

He first started uploading videos on electrical engineering and circuitry in January 2021. "I learned how to shoot and edit videos online, which I don't find difficult at all," he told Hubei Daily in June 2022. "All I use is a smartphone and a phone holder." He now has over 1 million followers on the platform.

The live-streamed class started in May 2022. Wang bought a blackboard and a box of chalk and created his own classroom.

Zhang Yang, a 20-year-old from Nanjing University of Science and Technology, majoring in electric engineering, has been a regular viewer of Wang's class since January this year.

"Viewers of his class are of different ages and come from all over China. We can have live audiochats with Wang, ask questions and have in-depth discussions," Zhang told Beijing Review, adding "I hope to become a teacher of electric engineering just like him."

"I am now in good physical shape and I will continue doing this until I am too old to do so," Wang Guangjie said.

Learning never gets old.

(Print Edition Title: The Silver Screen) 

Copyedited by Elsbeth van Paridon 

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