When older students were asked in which dynasty the Great Wall was built, they looked blank. "I just know it was used for defence," said one.
Although Hong Kong is to become part of China in a matter of weeks, children's knowledge of China is superficial and their perceptions of Chinese people are quite negative.
A survey by the Hong Kong Psychological Society found that just over half the respondents regarded mainland Chinese immigrants, who arrive at the rate of 150 a day, as rude, dirty, ignorant bringers of "social evils", such as spitting. Only 27 per cent had any positive comments, aside from describing mainlanders as hardworking and frugal.
"It is very clear that many Hong Kong-born people do not like people from the mainland. They view themselves as different from the mainlanders. They believe people from China are inferior," said Dr Chiu Chi-yue, psychology lecturer at the University of Hong Kong.
Children, the vast majority of whom have never been to China, get their views from their parents. "They are brought up with little knowledge and few connections with the mainland," notes Dr Lam Shui Fung, an educational psychologist.
Under colonial rule, school textbooks - only now being revised - barely touched on China. Although many of the older generation came as refugees from China, the country's isolation has meant that for many children images are distorted and out of date. However, increasingly these old prejudices are being removed as schools take part in exchanges with Chinese schools.
The Hong Kong Federation of Youth Groups has organised study tours to the mainland sponsored by companies in the colony and these have become increasingly popular. Last summer, some 300 children applied for the 30 places on the exchange. Other organisations such as the YMCA and Caritas have also set up exchanges. But the closest links to mainland students have been forged when schools twin themselves with schools across the border. When the Canadian International School organised its first exchange for its 8th graders (15-year-olds) to Foshan in China the students were amazed.
"We expected the people to be fairly backward, but they weren't. They were just like our next-door neighbours," said Ivan Tse and Janny Chan.
"They even play the same games as us," said other students who added they were surprised to find they had so much in common with the mainland students.
Paradoxically, the mainland students appear to have a better understanding of Hong Kong and its history than the colony's students have of China. They often watch Hong Kong television, and China's state-run television has been running documentaries on Hong Kong. They idolise Hong Kong pop and kung fu stars and a huge propaganda drive within China has given them more knowledge of the history of the place.
None the less, they realised that Hong Kong is not paved with gold. "Hong Kong people really work hard," said one of the Foshan students.
English Schools Foundation secondaries - which once educated the sons and daughters of the colonial lite but which now have a wide cross-section of nationalities - have increased their Mandarin teaching in recent years. It was the Mandarin teachers at Shatin College ESF school who helped the Foundation set up the Nanjing Foreign Languages School. "If you are doing Chinese studies, you need to experience the culture," said ESF Secretary Jennifer Wisker.
The students stayed with the Nanjing families and were pleasantly surprised by the living conditions. All households had fridges and televisions and were quite comfortable. "A lot of barriers and prejudices were broken down," said David Cottam, headteacher of Shatin College.
"Teachers thought the teaching would be rigid and formal but they were impressed with the warm relationship between teachers and students, " Mr Cottam said.
More radically, another ESF school, South Island has organised cross-curricular field trips to Cha Sai village across the border.
"It was more than just a 'look see'," said Ian McKirdy, head of geography at the school. Children went into farmers' homes and were also able to observe the seasonal cycles. They then returned to Hong Kong to do follow-up work on what they observed. "No matter how we prepared them, they were surprised at how poor and backward it was."
Teachers admit that the numbers of Hong Kong children going on such trips is small: "It is still not the norm for schools to organise exchanges," said one secondary teacher who is trying to convince her headmistress of the value of exchanges.
The number of Chinese children visiting Hong Kong is even smaller. Funding is sometimes provided by the Hong Kong schools but some teachers reported that Chinese children have had difficulty in getting visas for Hong Kong.