This thesis examines science in Primary Education in Ireland since the late 1800's. Much research has been done on science in education. Quayne (2003) described the development of post-primary science education in Ireland and drew attention to some features in primary science but did not seek to answer any specific questions. Kelham (1965) described the provision of science in schools in Scotland and Ireland. In this thesis the life and work of Henry Edward Armstrong and of William Mayhowe Heller, their philosophies into the teaching of elementary science and Armstrong's heuristic methods and his influence with Heller is discussed. The teaching of Science in Primary schools will be examined from the late 1800's with Heller organising the implementation of elementary science into the Irish National School system from 1900-1922 using Armstrong's heuristic teaching approaches. The thesis continues to analyse the teaching of science right through the century with the First National School Programme of 1922 to the 1971 curriculum and finally the revised 1999 curriculum. The history of Elementary Science gathered from documentary evidence together with the results of interviews with currently teaching and retired teachers are used as sources to provide an insight into science in the primary classroom from the late 1800's to the present day. Inspectors' reports and sample lessons from 1900 and 1999 provide a further insight into science teaching in the last century. Finally the thesis draws conclusions as to why science in the 1999 curriculum is considered by many teachers a new subject in Irish Primary Education. Elementary science is not a new subject in Irish Primary Education today. In fact lessons from the attempted 1900 implementation of science might even be applicable to the science curriculum of today.