Otago Science and Technology Fair chief judge Victoria Rosin (47) said a panel of 40 judges scrutinised 283 science exhibits created by 321 pupils from 27 Otago schools.
The prizegiving for the fair, which has been running for about 30 years, was held in the University of Otago's St David Lecture Theatre yesterday.
Ms Rosin said it was her fifth year in the top judging position and this year's ''refreshing'' exhibits were more ''quirky and unique'' than past years'.
Pupils had engaged their imaginations and the usual exhibits, such as the ''exploding Coke and Mentos'' exhibit that was presented most years, had been avoided.
Ms Rosin said year 10 Logan Park High School pupil Grant McNaughton (15) had won ''best in fair'' for his ''novel'' exhibit, ''Branching Out''.
Grant was nominated for the national Realise a Dream competition, which awards 20 secondary school pupils prizes such as cash scholarships and international travel.
Grant said he was ''amazed and surprised'' his exhibit won the top award.
The exhibit tested a Leonardo da Vinci theory that if a tree was sliced horizontally below a certain point, the total surface area of the slices would be the same at any point up the tree. If all of a tree's branches were ''folded up'', an even trunk would be created. The theory had never been widely tested because of the difficulty of dissecting a tree.
During his winter school holidays, Grant photographed and examined a variety of trees, which revealed da Vinci's theory was relevant.
And the polymath's theory could be applied to other biological, systems such as blood vessels, Grant said.
''And the theory works for non-biological situations such as rope and string. All the strands in the string, put together, equal the same surface area of the main piece.''
Premier prize results
Best in fair: Grant McNaughton (Logan Park High School) ''Branching Out''; Most promising young scientist senior: Alex Thomson (John McGlashan College) ''What's with the St Clair Sand?''; Most promising young scientist junior: Blake MacDade and Ollie Meikle (Kavanagh College) ''Footprint Forensics''; Division of Sciences award: Meran Campbell-Hood (Logan Park High School) ''Elementary Observations''; Future Scientist award: Cameron Monteath (Dunedin North Intermediate) ''Musical Beans''; General excellence: Tiahli Curran-Hogg (Otago Girls' High School) ''Wood Moisture Content''.
