Every morning when the national anthem plays out in Thai schools, students are expected to stand still in deference as the country’s flag is raised. But last week some sent a defiant message, raising their hands in a three-fingered salute – a gesture borrowed from The Hunger Games that is used widely by Thailand’s growing pro-democracy movement. Others gathered on school grounds to hold up sheets of blank paper.

For more than a month there have been almost daily student-led rallies spreading across the country, including a demonstration in Bangkok last weekend attended by more than 10,000 people. Observers are astonished by how rapidly the protests have spread, by how young people are challenging traditional hierarchies, and by the boldness of their demands, some of which relate to the powerful royal family.

“Everybody in Thai society has been very surprised by what is happening right now,” said Kanokrat Lertchoosakul, a lecturer at Chulalongkorn University’s faculty of political science: “We have never ever seen a phenomenon like this.” As well as university students, children as young as 13 or 14 were organising flash mobs, she said.

The protest movement is not centrally organised. Instead, different groups have used social media to coordinate rallies across the country, driven by anger at a military-backed government they accuse of eroding democracy and holding their country back.

Protesters are calling for the prime minister, Prayuth Chan-ocha, who first came to power during a 2014 coup, to dissolve parliament, for an end to the harassment of activists and for reforms to the constitution, which was written under military rule and has entrenched the army’s power.

Some have also called for changes to curb the power of the monarchy, in speeches that until recently would have seemed unthinkable.

Such comments carry huge risks. Though the king has apparently requested no prosecutions for now under the country’s strict lese-majeste laws, at least 10 pro-democracy protesters have been arrested on other charges including sedition, which carries a sentence of up to seven years.

The group Thai Lawyers for Human Rights says it has documented 103 cases where students have been harassed or prevented from expressing their political views, including by making the three-fingered salute, wearing white ribbons or holding pieces of blank paper. Last week Unicef released a statement calling for “children and young people’s right to freedom of expression” to be upheld.

Thailand’s education minister, Nataphol Teepsuwan, has said students have the right to express their views.

Kanokrat, who has interviewed dozens of young protesters, said that while students’ right to voice political opinions was protected in the constitution, most schools were trying to stop any form of protest. “In reality, in a very conservative and moralist society like Thailand, the controlling power inside the school is under the hand of the individual teachers,” she said.

At a rally outside the education ministry on Wednesday, Nataphol was jeered by students – a fair cry from the respectful treatment that students are usually expected to give their elders. Nataphol sat down with campaigners to discuss their concerns, stating later that “the government is always willing and ready to listen to all its citizens”.

A grade 11 student who was among those who protested at school and asked not to be named, said young people wanted freedom of expression. “We want a true democracy where you can speak however you want without being arrested,” she said.

She had followed protests on Twitter and decided to take part with friends. “At first when I thought about it I was afraid, but because a lot more people [took part], after, the feeling was that I want to fight,” she said. She had not faced any repercussions.

Kanokrat said social media was one of the factors that had led students to become emboldened in their protests. Online they had found a community of people with similar opinions who would rally to support one another.

“I interviewed a medical student and they said they have to work very hard studying, but that at night they have to work hard to promote the hashtag,” she said. Protesters are using everything from Tinder to TikTok to spread their message, often using symbols and satire.

Online and at rallies, yellow “missing” posters are shared, featuring the faces of disappeared activists. Students make subversive use of cultural references, from Harry Potter to Hamtaro, a Japanese cartoon hamster. In public places, young people sing an adapted version of the Hamtaro cartoon’s jingle while running in circles, as if in a hamster wheel. As they run, they sing: “The most delicious food is taxpayers’ money.”

There is a long tradition of Thai protesters using symbolism. “This happens when you grow up in dictatorship or highly repressive regime,” said Dr Aim Sinpeng, a lecturer at the University of Sydney. She said young people today produced references and satire that were “highly shareable and suited to social media”.

Speeches have become increasingly direct, with some speakers calling for the power of King Maha Vajiralongkorn to be curbed. Prayuth has told protesters not to involve the monarchy but said he will consider their concerns regarding the constitution.

Some have questioned why, if demands are being listened, peaceful activists are being arrested. “The government is trying to buy time by arresting activists one by one,” said Tattep Ruangprapaikitseree, the secretary general of the protest group Free People Movement, who faces multiple charges. “They think that the protest will dissolve, but they are wrong.”