Tommy Cheung Sau-yin had been civic-minded in his teens, even doing volunteer work while in Form Two. But it was not until a massive rally in 2010, which he attended with thousands of others, that he truly began to participate in social movements.
During the rally outside the former Legislative Council building in Central, which took on a carnival atmosphere, Cheung and others clamoured against a government plan to build an express rail link to Guangzhou. (The project is still under way.)
And in January last year, Cheung became a member of action group Scholarism - he is now the spokesman - joining them in braving the heat and marching on the government headquarters in Admiralty to oppose the proposed national education curriculum, which was eventually scrapped.
Cheung says his stepped-up involvement in social causes was inspired by his liberal studies class, which became a compulsory subject in the New Senior Secondary (NSS) curriculum in 2009. He was at STFA Leung Kau Kui College when he took it.
"It gave us the knowledge base and was a kind of awakening for me. We had the room to study social issues and discuss views in class," says Cheung, now in his first year at Chinese University's department of government and public administration.
Liberal studies has six modules: personal development and interpersonal relationships; Hong Kong today; modern China; globalisation; public health; energy technology and the environment. It covers topics such as the rule of law and Hongkongers' identity.
At Cheung's school, students also watched videos and documentaries such as RTHK's series Hong Kong Connection. Often they were split into groups for discussion before presenting their ideas to class.
Cheung sees a difference between students who finished the now-defunct A-levels and those who took the first Hong Kong Diploma of Secondary Education (HKDSE) Exam last year (part of the revamp that includes NSS) - with the latter group being more socially conscious.
"I think staging a march is a good way to fight for more political space. The number of people who show up is a good indicator of public opinion," says Cheung.
Scholarism itself was formed by Wong Chi-fung and fellow secondary school students in 2011 (Cheung found out about them through Facebook). Wong is a Form Five student at United Christian College who espouses democracy and political reform. The group's membership has grown from 150 last year to 400 this year.
If pressuring officials to scrap what activists see as misguided policies is a difficult task, so is teaching liberal studies.
A Professional Teachers' Union survey conducted from May to June showed that 78 per cent of 827 liberal studies teachers polled were facing a work-pressure level of seven or above, on a scale of 10. On average, each teacher was supervising 35.7 students per academic year.
Their biggest challenge, the poll shows, is guiding students on their research for the Independent Enquiry Study (IES), which is the basis of a school-based assessment (wherein the teacher's rating counts towards a student's HKDSE results) and culminates in a 4,000-word essay.
Form Five student Betty Kui, who is doing a project on online addiction, says she has paid more attention to news items since taking the class. But she is struggling to remember English words and complex terms used in current affairs. "I just want to pass the examination," she says.
Other difficulties faced by teachers are catering to students with different learning capabilities and preparing teaching materials. Developing students' critical thinking was also a challenge.
In another survey done in the past two months by the Liberal Studies Teachers' Association, 81 per cent of 160 respondents said the curriculum was too broad. Half of the respondents also said it was too difficult.
Most teachers in both surveys supported a reduction in the number of modules, citing overlapping content.
Many respondents said the public health module should be removed, along with technology and environment, saying it is better to integrate them into the other four modules.
"[Teaching liberal studies] is a tiresome process," says Colin Lai Tak-chung, who teaches at Munsang College in Kowloon and whose wife is also a liberal studies teacher. "Every day we are busy. When we are at home, we are often working on different computers."
The teachers have to keep up to date on news in the city and worldwide then translate complex issues into materials that will be easily understood by the children.
To make matters worse, their workload became heavier after the Education Bureau recently scrapped a special subsidy for liberal studies. The withdrawal led to the sacking of hundreds of teaching assistants, says Lai, who is also the vice-chairman of the teachers association.
"We will have to take up a lot of administrative work. We hope we will have more resources from the bureau and more training for teachers because it's a subject that needs ongoing training [as] new social issues and concepts keep cropping up," Lai says. "Most of the time, we need to look beneath an issue to understand what is happening. We come from different disciplines so sometimes we may not have the background needed."
A history major, Lai says he sometimes borrows ideas from or consults other colleagues to enrich his perspective. He asks for help from biology teachers, for instance, to understand health issues.
Despite the heavy workload, the teachers are happy to see growing social awareness among students.
Lai says all his efforts are worth it - and beneficial to the growth of civic society.
"Before, teenagers did not like to read newspapers, nor did they care much about current affairs. Now, at least, we have a platform requiring them to read newspapers and discuss issues. Some students have started sharing their views on Facebook. There are also more books on various local issues in bookstores," he says.
"Since the subject was introduced, the number of young participants in the June 4 rally in Victoria Park has increased tremendously," Lai says, referring to the annual vigil marking the 1989 Tiananmen Square crackdown.
"I don't have the figures, but according to news reports, more teenagers have joined the rally in recent years. Last year, I went to the anti-national education protests and I saw a lot of my students there. They also shared photos on their Facebook walls. The effect of the subject was quite impressive.
"I can't say all the students are like that but at least 10 or 20 per cent of the students have become interested in issues."