China's "Teacher's Day," celebrated on Sept. 10 every year, holds special meaning for 19-year-old "student teacher" Wang Yulong, who studies at Tsinghua University.

Recently he received heartwarming presents from primary school students in Indonesia as a token of their appreciation. "Thank you for everything and welcome you to come back to Bali," read a greeting card written by a child named Ika.↳

Those cards with crooked "Thank-you" notes and photos with innocent smiling faces once again reminded Wang of his time as a volunteer teacher in Bali during this summer holiday, when the kids there were surprised and excited by the science world that he and his partners created with many simple but interesting scientific experiments.↳

"Kids are born with a strong curiosity. I saw their passion for science in their eyes and heard their cheers," Wang recalled, adding that this experience as a volunteer science teacher had given him a profound understanding of the rewarding role of a teacher.↳

Wang is majoring in mechanical engineering at Tsinghua University, one of China's best institutions of higher education. Tsinghua requires its students to conduct in-depth scientific research and also encourages them to offer social services not only for the country but the world, according to Professor Li Yongjian, one of the instructors of the volunteering team.↳

Every year, students and staff members from the university conduct industry research in Singapore and Indonesia. Even as a freshman, Wang got the opportunity to participate in this endeavor, as part of a program named CURES, which stands for culture, university, research, education and sustainability.↳

This year, rather than the customary two-week visits aimed solely at gathering reports from local governments and businesses, the team decided to deepen their understanding of the culture and society of Indonesia through volunteer service.↳

With support from an educational foundation in Bali, the 19-member team chose to volunteer their time by teaching in three public primary schools for over 200 students.↳

Their preparations began two months in advance, involving assessing the needs of local schools, developing teaching plans and conducting training sessions. The team designed nine special courses, including art, Chinese culture, P.E., a paper airplane competition, and most importantly, science.↳

Wang taught science to fourth-grade students, and despite language barriers, he was surprised by the students' kindness and cooperation, as they warmly greeted him during his first class. To capture the attention of the students, he conducted several simple scientific experiments, such as creating a "fruit battery" using a lemon, an LED light, zinc, and copper sheets and wires.↳

Wang shared an amusing teaching memory. "I practiced all the procedures the night before to ensure there were no mistakes. However, I didn't anticipate that Bali's lemons were more sour, so I had to make adjustments by placing the electrodes closer together. Nevertheless, things went smoothly, and I can still vividly recall the moment they surrounded me, laughing and screaming when the light came on."↳

"Later I also taught them how to make 'fruit batteries' with apples, tomatoes and oranges in the same way. I even designed two mistakes to guide them to think independently," Wang added. "Now I know how much care and thought it takes to be a teacher."↳

Besides teaching science, the Tsinghua volunteers also shared details of traditional Chinese cultures, festivals and snacks, like mooncakes, with local kids.↳

Yu Yong Chia, a 35-year-old Indonesian, worked as the guide and translator for the Tsinghua team throughout the journey.↳

"I have been teaching Chinese for 13 years, and I would like to give full marks to these 'student teachers.' They may lack teaching skills, but their sincerity shines through," Chia said.↳

He said that this year marks the 10th anniversary of the proposal of the Belt and Road Initiative, in which Indonesia is a participant, and he hopes to see more people-to-people exchanges.↳

Professor Li also expressed his pride in his students. "They are still kids in my eyes, but now they have cultivated a strong sense of responsibility. Nothing makes a teacher happier than witnessing the growth of their students."

Editor: Guo Lili