Smoke alarms, yoghurt and crickets are at the centre of investigations at Carisbrook School.
About 75 year 7 and 8 pupils have spent term two, and some of the school holidays, working on projects for the Aurora Energy Science and Technology Fair.
Nicole Mei and Amira Soroka (both 11) and teacher Ann Ruxton were at school on Friday working on the girls' project.
They were investigating whether ionisation or photoelectric smoke alarms react faster to smoke.
To do this, they tested about five different types of smoke alarms by putting them in a tank, filling the tank with smoke and timing how long it took for the alarm to start.
They repeated this about three times each to make sure their findings were accurate.
One of the fastest times was about 11 seconds while another took about a minute.
The girls visited St Kilda Fire Station before they started their investigation to find out more about the two types of alarms.
Amira said she enjoyed getting to sit in the fire truck.
Ms Ruxton said there had been a "great response'' from members of the community who were willing to help the pupils with their projects.
"It's the link with the community that's really important.''
The pupils had been working on their projects since the start of term two and spent about three sessions on them every fortnight.
Ms Ruxton, Nicole and Amira were "stumped for ages'' trying to figure out the best way to get smoke into the tank "without burning the school down'', she said.
Between 10 and 20 pupils would be chosen to enter their projects in the fair.
A representative from the University of Otago would help make the decision.
The other children would take part in an in-school presentation.
The fair will be held at Otago Museum from August 6 until August 12.
Last year, 309 pupils from 27 schools in Otago presented 264 projects.
JESSICA.WILSON @thestar.co.nz
