The A-State form of the State-Trait Anxiety Inventory (STAI) is used to assess transitory emotional states provoked by an individual's perceptions of a specific situation as personally threatening. These experiences produce emotional reactions which characteristically involve STAI was found to be a reliable and easy-to-administer instrument for measuring preservice elementary teachers' anxiety about teaching science. measuring preservice elementary teachers anxiety about teaching science. The instrument has been used to examine: (1) effect of a sequence of science content courses; (2) the relationship with attitude toward teaching science (as measured by the Modified Bratt Attitude Test); (3) effects of various teachers; (4) effects of staffing patterns; (5) relationship among various demographic variables; and (6) the longitudinal effects of subsequent academic experiences. Results indicate that the instrument can measure changes in anxiety about science teaching in specific situations and that it is possible to identify subjects (N=544) who are extremely anxious about teaching science by comparing A-State (transitory) with A-Trait (relatively stable individual differences in anxiety proneness) scores. (Author/JN)