In Hong Kong, all children have to go to school. That is the law. If you drop out of school, your parents can get into trouble. Hong Kong citizens are entitled to 12 years of free education.
Yet schooling hasn't always been compulsory: it wasn't even compulsory 50 years ago. Some of you may have heard your parents say how lucky you are to go to school: they mean it, too. That's because during their lifetime, education wasn't free for everyone.
Education is a way to gain knowledge. Nowadays, students learn languages, mathematics, history and science in school.
Yet since the start of human history until the Roman Empire, knowledge had a broader definition. For men, it included survival skills, some literature and philosophy - and war strategies. Women learned how to cook, maintain a home and take care of their family.
The curriculum and content of education must constantly change to keep up with life's demands. In some nations - especially in the West - religious study was once a major subject, with churches setting up schools to spread their religions. After the industrial revolution, children had to learn the 'three Rs', reading, writing and arithmetic. Later, when innovation and creativity became important, science and engineering became prominent school subjects.
This week, we'll take a look at the history of education:
Long before schools existed, education already played a big part in ancient tribal life.
While ancient man may not have solved quadratic equations, or written software codes, he did learn - essential survival skills. He learned to hunt for food, and use spoken and sign languages to communicate.
Instead of going to school, he learned skills from his parents and peers.
The start of civilisations
A few civilisations first spearheaded the start of formal education. They were the Romans, Greeks, Chinese, Indians and the Middle-Easterners. Back then, education was private: learning to read and write was a privilege restricted only to wealthy or powerful people.
Most civilisations based their curriculum mainly on religious studies, and put a huge emphasis on humanity, literature, arts and philosophy.
In Greece, education was slightly more all-rounded, catering to everyone. Many children were able to go to junior schools to learn how to read and write - even the poor.
However, in senior years, rich children continued their studies, and poor children took apprenticeships. Science was taught in some schools, and physical education was a big part of the curriculum.
China, too, had a different curriculum - it didn't have much religious content. Instead, students studied and recited the words of philosopher Confucius.
Girls were excluded from education in most civilisations, except in Rome.
The Middle Ages
Between the 5th and 15th centuries, Christianity spread rapidly in Europe. Churches set up schools to prepare students for ministry and gospel-spreading work.
Students in the West were taught Latin because it was the official language used when discussing the scripture. They were also taught how to write Latin so that they could help to copy the bible.
However, that kind of education style was passive. Students weren't supposed to question what they learned. Instead of observing and discovering the truth by themselves, they were expected only to listen and memorise. At that time, most women were not allowed to study. At the close of the Middle Ages, the urge to learn about humanity and philosophy returned. People started to show an interest in science. In China, an Imperial Examination was set for people who wanted to become one of the empire's officials. The syllabus of the exam covered mostly classical Chinese literature, giving rise to schools that specialised in the subject.
In the West, capitalism emerged slowly in the 18th century, and religion no longer played such a big part in people's lives as it had in the past.
In the world of capitalism, life is about spending money. To get people to spend, many creative products were needed. This led to a change from an arts-oriented education to something more practical. Creativity was needed; subjects such as science and engineering slowly grew more popular in the 19th century.
In the United States, in particular, education became more accessible in 19th century. A few state-funded schools appeared at the start of the century, and by the turn of it, a national school system was already in place - with girl students included.
Since then, many countries have followed in the same footsteps, and made education a 'must' for every single citizen. The choice of subjects has also widened to cater to the different needs of each student.
How information spread
Before writing was invented, speaking was the only way to share detailed knowledge with others. But speech is not the most effective way because it is hard to remember.
Folk songs and poems - rhymes, in general - existed in ancient cultures to help humans to recite knowledge and information.
Yet, the word-of-mouth approach is far from perfect. A speaker can get the story wrong, and there is always room to change a story to 'improve' it. Also the listener may misunderstand the story. And there is always a limit to how much one person can remember.
There is a saying in English, 'Don't re-invent the wheel'. In other words, don't start anew each time - instead, build on the knowledge of those that have done it before.
To investigate something, first we base our investigation on what we already have. The ability to store information on a paper - or animal hide, in the past - allows us to refer to what has been done before and make logical choices about how to proceed. After we discover new knowledge, we can use scripts to record it, so in future people can read our ideas.
However, while we could store information in the past, it was hard to share it. Copying a book meant someone had to write it by hand. It could take months, if not years. Books and documents were costly.
The invention of the printing press made knowledge accessible. It made it possible to create thousands of copies of written texts quickly - and economically. Therefore, knowledge became affordable for many people. Newspapers were booming at this time. People were able to receive information faster - and the literacy rate increased.
The birth of the internet took the idea of sharing knowledge to a new level. Anything you want to know is only a few clicks away. Learning has never been so simple as students choose what and when to learn. Yet the openness of the internet has led to other worries. Often it is hard to tell if something is true or false.
Also, while many Hongkongers are lucky enough to have the internet, almost 70 per cent of the world's population is not online.
The net is still a costly education tool for many people. Pushing for all-things-digital in education too fast may create another social barrier - one we have fought to dissolve: the rich/poor divide.