Until confronted with an emergency, people don't understand that knowing first aid can be the difference between life and death. If you're not equipped to deal with an emergency, you're helpless. This blunt ad uses an invisible barrier to dramatise that feeling. A mother sees her son in trouble after he hits his head jumping into their swimming pool. She frantically leaps into the pool only to land on the water's surface, unable to penetrate the invisible barrier and offer assistance. A simple statement backs up the stark reality. 'If you don't know first aid you can't help.' (https://www.dandad.org)