Children's Concepts of Volume and Flotation.

In a pilot study children aged 7 to 9 years and 11 to 13 years were asked to judge which one out of three wooden blocks would float (or sink), given weight and volume information for each block relative to a block that was known to float (or sink). Analysis of explanations indicated that judgments may have been based on the size-weight illusion. The basis of flotation judgments was explored more extensively in Experiment 1. A test for judgment of volume based on information integration theory showed that children aged 7 to 14 years can accurately judge volume by integrating three dimensions according to the multiplicative rule. A rule assessment of their flotation judgments showed no age differences in initial rule, weight rules being most popular. However after feedback there were marked age effects, the 7-9 year olds abandoning their initial rule without finding an alternative. The 11- to 14-year-olds, however, were mostly able to find the correct flotation rule.