This year's BT Young Scientist and Technology Exhibition is under way at the RDS in Dublin.
As the event approaches its 50th birthday next year, the organisers say they would love to hear from former contestants, teachers and others who may have memorabilia such as photos from the competition's earliest years.
It is 49 years since two young physics lecturers first organised a national science competition for school students, modelling it on an idea they brought back from the United States.
Back then, 230 teenagers took part in the first event.
More than 4,000 entered this year's competition and by this afternoon 1,300 of them will have set up their stands and the first round of judging will begin.
Next year, the Young Scientist reaches 50 and the organisers say they have very few photos and other memorabilia from the early days.
They have appealed to anyone who may have photos they would like to share to contact them by email at firstname.lastname@example.org.