It is day two of the BT Young Scientist and Technology Exhibition in Dublin - the first day the public get a chance to see the range of projects on show.
The event at the RDS is open until Saturday, with an estimated 50,000 visitors expected.
More than 550 projects from schools, both North and South, are on display.
Climate change and pollution feature strongly.
The overall winner will be announced tomorrow evening.
In 2010, Diarmuid Ó Mathúna published his groundbreaking book 'Integrable Systems in Celestial Mechanics' which produced a solution to what is known as the Euler problem.
Euler was an 18th century Swiss mathematician.
Mr Ó Mathúna’s work has inspired students of mathematics, including the 2012 winners of the BT Young Scientist and Technology Exhibition, who based their project on his work.
Today the mathematician visited the exhibition and met students including Benedek Goz, one of two Synge Street CBS brothers who have two separate mathematical entries in this year's competition.
Synge St in Dublin has a strong track record at the exhibition, with students from the school scooping top prizes on a number of occasions in previous years.