Tickets for today's session of the BT Young Scientist Exhibition have completely sold out.
Organisers are advising people not to attend the event at the RDS without a ticket, as they may be refused entry.
Tickets remain available for the final day of the Exhibition tomorrow and can be bought online at www.btyoungscientist.com/ticketing.
Today sees 140 awards handed out to students, with one of the 550 projects to be given the top prize.
The judges say issues like homelessness, transgender rights and mental health feature in a lot of the projects this year.
One of the judges, Dr Jones Irwin, thinks this is a positive sign.
"I volunteer my time because I really believe in the students and their work. The projects have a real sort of social-political significance," he said.
"That's what we really need in Ireland at the moment. For teenagers to be waiting out some of the main issues in the culture and the society," he added.
An overseas trip to a remote corner of sub-Saharan Africa is the thrilling prize that awaits the lucky winner of one of the top prizes at this week’s BT Young Scientist and Technology Exhibition in Dublin.
The Irish Aid backed travel bursary will go to this year’s winner of the ‘Science for Development Award,’ a special category prize presented by the judges to the project that they believe best addresses a development challenge facing communities in poorer regions of the world.
Also running in the RDS is the ninth RDS Primary Science Fair.
It is hoped primary school students engaging in science projects will be key in filling skill shortages in STEM areas in the future.
90 schools are taking part over three days.
Each school has entered a scientific investigation which involved the whole class.
The fair is one of three involving over 7,000 eight to 12-year-olds this year.
Next week the event will travel to Limerick and in June it will return to Belfast.
Projects include 'What if the earth stopped spinning?' and 'Can we design a hover car that cleans as it drives?'.
"We know that there is a shortage in the skills pipeline coming through and particularly so in the girls that are engaging at secondary school and third level and beyond," said RDS Science and Technology Programme Manager Karen Sheeran.
While it is a non-competitive event, the children still benefit from presenting and feedback.
"Starting young is key and ensuring that both girls and boys have equal opportunities - irrelevant of their backgrounds - to achieve what can be for them," she added.