SECONDARY school students are invited to take part in an inter-school competition of study projects on local history. The competition, organised by the Hongkong Museum of History, aims at encouraging secondary students to take part in investigations on local history and culture, and thus enhance their understanding of Hongkong's heritage. The theme this year is ''Traditional Trades and Crafts in Hongkong'', covering paper craft, ivory and rattan industries, head-shaving, rice trade, old pawning business, Chinese herbal medicine shops and dough-figurine making. The study report should take the form of a written report, complemented with relevant models, objects collected, photographs, slides, audio-tapes or video-recordings. The first three winners will each receive, in addition to trophies, cash prizes of $5,000, $3,000 and $2,000 respectively. Entry forms are available at the Museum of History or by contacting the museum's Education and Extension Services Section at 367-1124. Completed entry forms should be sent direct to the Hongkong Museum of History, Kowloon, Tsimshatsui, by June 30. The completed study reports should be delivered on or before October 31. The panel of judges will include five leading experts on local history and craftsmanship. Among them are: Ms Jane Cheng Chee-hing; Senior Inspector (History), Education Department; Dr Cheng Tak-wah, Supervising Editor of the Joint Publishing (HK) Co Ltd,and Dr Choi Chi-cheung, lecturer, University of Science and Technology.