A group of Rotorua children are using science to prove whether the basis of the legendary love story of Hinemoa and Tūtānekai is true.

They concluded it very well could be.

Te Arawa Lakes Trust's Te Tūkohu Ngāwhā Mātauranga Māori Science and Design Fair is in its third year.

It aimed to celebrate the intersection of Mātauranga Māori (Māori knowledge) and science, and give students a platform to showcase innovative projects and designs.

There were 35 exhibits in its first year. Last year grew to about 40, and this year more than 100.

Topics covered five categories and ranged from projects focusing on water quality and rongoā (traditional Māori medicines) to investigating a legendary love story.

The latter involved a group from Te Rangihakahaka Centre for Science and Technology looking at the legend of star-crossed lovers Hinemoa and Tūtānekai.

The story, told in the song Pokarekare Ana, is about how beautiful chief's daughter, Hinemoa, fell in love with lower-ranked suitor, Tūtānekai, and swam across Lake Rotorua to be with him on Mokoia Island when she heard his flute calling to her.

The students decided to test whether she would have been able to hear the sound of his flute from across the water.

The group looked at how various conditions impacted on how loud the flute would have been and how it would have gotten louder as Hinemoa swam across Lake Rotorua.

With transmission loss expected between 30-40 decibels, it would have been soft at first: "a sound like wind in the trees".

Conditions needed to be calm. No wind; glassy water; cold; overcast and no ripples.

Conclusion: "it would be audible".

Te Arawa Lakes Trust environment officer Keeley Grantham. Photo: LDR / Laura Smith.

Te Arawa Lakes Trust environment officer Keeley Grantham says categories were broad, which meant there was an "amazing array" of projects.

Among her favourites was a Te Akau Ki Pāpāmoa School project, which looked at trapping a pest crab species in Tauranga Moana.

Named He Taonga tuku iho te Pāpaka, the project detailed the history of the Asian paddle crab and how it impacted on native species of pāpaka (paddle crab), as well as how the aggressive invaders could be tackled via a trap.

Keeley says the fair's purpose was important.

"We're not just looking at Western science, we're looking at mitigating environmental issues through a whole heap of different lenses, especially through our te ao Māori lens.

"And enabling kids to broaden their scope of knowledge and just really build upon what they already know and just continue networking and sharing their kaupapa with other tamariki and other people that work in this field."

About 16 kura (schools) were involved and "at least" 250 children. Groups and individuals could take part.

The fair began on Wednesday and a prizegiving was held on Thursday evening.

LDR is local body journalism co-funded by RNZ and NZ On Air.