The classes are part of a drive to make sure more people get first aid skills. At the moment, all schools in Wales and Northern Ireland take part in these lessons, that's because it's part of their national curriculum. In England and Scotland only some schools teach first aid.
St John Ambulance want the government to make sure that this changes, so all schools take part.
These life saving skills can be really fun to learn, even when you get to pretend to be an injured patient, but they can also save someone's life.
St John Ambulance hope that by 2011, first aid lessons will be part of national curriculum across the UK."