Isobel's parents, Marcus and Sarah, were told her life expectancy was between 10 and 14 days - but she made it to five years old.
Each child and member of staff at Newland St John's school in Hull released a pink balloon, which was released in celebration of Isobel Meyer's life.
Every balloon had a tag attached to it, explaining the significance of the balloon, inviting finders to make a donation towards St Andrew's Hospice in Grimsby.
Children at a primary school have been celebrating the life of a brave five-year-old who was given two weeks to live at birth.
Isobel Meyer had a rare heart condition and was born at 32 weeks. At her school - Newland St John's in Hull - children held a superhero day in her honour.
They raised money for St Andrew's Hospice in Grimsby, where Isobel was a regular visitor and their "poster girl".