Weerasak Srisuknimit, of Mahidol Witthayanusorn in Nakhon Pathom, won a gold medal, while Jirarat Jirarayaphong, of Bangkok's Triam Udom Suksa, and Thawatchai Chaijarasphong, of Bangkok's Assumption Bang Rak school, each won a silver medal.

Phattharawadee Prayuenyong, of Mahidol Witthayanusorn, in Nakhon Pathom, won a bronze medal.

Weerasak, or "Jip", said he had relied mainly on textbooks and lectures for his studies and had received no extra tutorials.

Thawatchai, or "Benz", who won a silver in the same competition in Taipei last year, said chemistry was his favourite subject and that he was proud to have won another medal.

Jirarat, or "Moji", said she loved laboratory tests as they showed chemical reactions taking place and an interest in chemistry inspired her. Students who may not like the subject had to work harder to get good grades, she said.

Phattharawadee, or "Fern", said she played sports and joined other recreational activities to relax. She said support from her family and schoolmates were crucial to her success.