Two approaches to teaching and learning in primary science which involve 'inquiry' are 'discovery' and 'investigating'. This thesis compares the teaching approaches associated with these terms, their interrelationships, and teachers' theories about them. On the basis of a literature survey, descriptions for these terms, and relationships between them have been established. A ten criterion analytic framework summarising differences between 'discovery' and ' investigating' was developed. A modification of a schema from the Ford Teaching Project was also developed to indicate the hierarchical relationships between the three descriptors. The analytic framework was used to analyse thirteen teacher's theories about 'investigating' as it relates to the NSW primary science policy statement, Investigating: Science (K- 6) and to identify the extent of 'discovery' components. Verbal and practical indexes, together with a 'discrepancy indicator' were used to quantify the ' investigating' orientation of teachers' verbal and practical theories, and the differences between them. Data sources included interviews, lesson observations using a revised SPOC Schedule, teacher programs and worksheets, post-lesson discussions and researcher notes. Twenty three percent of teachers were found to be 'investigating' in both interview and in their classroom practices, and 86 per cent exhibited classroom practices that were less 'investigating' than was indicated from pre-lesson interview statements. Possible influences modifying the 'discovery' oriented secondary school science framework towards a more 'investigating' orientation were partially explored. Modifying influences found, in ranked order were: association with 'investigating' teaching peers; appropriate preservice experiences; and no modification occurring as a result of inservice courses attended.