The RDS Primary Science Fair begins in Dublin today with almost 3,000 primary school children taking part.
The three-day event is organised by the RDS but runs alongside the BT Young Scientist and Technology Exhibition, which opens to the public today.
This is the ninth year of the fair which involves a whole class undertaking an investigation using STEM skills and then exhibiting their findings.
Each day a different group of schools will display their projects in a non-competitive environment.
In recent years the fair has expanded outside Dublin; 7,000 pupils will also take part in Limerick next week and in Belfast in June.
Among the questions being posed are "Why do basketballs bounce?", "Can a parachute save an egg from a two-storey fall?" and "Why do onions make us cry?".
If you could capture the energy in the RDS Primary Science Fair you could power a small country! pic.twitter.com/fUe6MdMKr3— Will Goodbody (@willgoodbody) January 11, 2018
Second round judging in the BT Young Scientist and Technology Exhibition will take place today and more than 60 science related shows will begin.
Industry exhibitors will also have their stands open.
Former hacker Kevin Mitnick, who was on the FBI most wanted list, will also give a talk this afternoon, as will Irish "astronaut in training" Norah Patten.
Organisers have warned that because the ticket situation is tight, intending visitors should book online before travelling to the venue to avoid the disappointment of potentially being turned away.