Validating developmental sequences in the domain of astronomy using latent trait techniques
The present study was a systematic investigation of developmental skill sequences in the early science domain. Three developmental sequences in the area of astronomy were investigated; knowledge about earth, light and motion. Test items were developed reflecting developmental sequences based on the cognitive processes that are necessary for understanding each task. Data were collected from 1595 kindergarten children from six geographically diverse areas. Latent trait models were constructed to reflect the hypothesized developmental sequences by allowing discrimination and difficulty parameters to vary or by constraining them to be equal. Preferred models were obtained by statistical comparison with other models. The knowledge about light and motion were in the hypothesized developmental sequence. Astronomical events that contradicted personal experience, required causal explanations and consisted of extended causal chains were the most difficult for kindergarten children to understand. Investigations concerning the mechanism for conceptual change are necessary.