A 95-year-old professor at China’s Tsinghua University recently offered an online course on quantum mechanics.

The professor Zhang Li is the oldest teacher in the university, and was assisted by one of his former students, Hu Jiazhong, in running the online classroom.

“Hu is an excellent experimental physicist, and his presence will enrich the content of the course and make it more advanced,” Zhang said prior to the course.

The professor has taught the postgraduate course “Frontier Problems of Quantum Mechanics” for 22 years since 1998, which has been attended by many senior students every year.

“Mr. Zhang’s course is not something that can be found in textbooks. What he teaches is on the cutting edge, which books might not be able to explain. We can learn a lot from it,” said Hu.

The 95-year-old said his age was the biggest challenge for him to teach the course as he doesn’t think as quickly as he did in his younger years. However, his resounding laugh still makes it hard to believe that he is actually a man of 95 years.

“This way of teaching is terrific, especially for the students,” Zhang said, explaining as students are usually shy to ask questions in normal classes, but now they can ask the teachers questions in group chats at any time.

Zhang has been “racing against time” in order to prepare as much as possible for the classes. He gets up at 5 a.m. every day to read documents, and does further reading in the office when he doesn’t have any classes. The professor works at least 8 hours per day, and sometimes even on Saturdays.

Apart from teaching classes, Zhang also frequently attends various lectures held by Tsinghua University’s Institute for Advanced Study. He always sits in the first row, which leaves a deep impression on the students. “He listens to almost all the lectures, and always raises questions,” said Han Tonghang, a student from the Department of Physics.

Zhang said that he is filled with energy every time he teaches. “I will give up teaching if my brain stops working one day. But I will not surrender until that day comes.”