More than 1,200 balloons will be released into the air tomorrow at Bedwas Infants School.
The balloons will be released at 3.15pm from the school grounds and is part of a fundraising drive to improve the school’s facilities.
Over the next six weeks the children will plot the locations from where the balloons are returned on a map.
A special prize of a hot air balloon ride for two will be awarded to the person who bought the balloon that travelled the furthest distance.
The person who finds the winning balloon ticket will also receive a small prize
A number of companies have sponsored the event including ExxonMobil Chemical, Caerphilly Timber Supplies and Cled Williams Coaches.