Abstract: The purpose of this study is to explore the levels and characteristicsof the development of children's cognition of velocity at different ages.The subjects were 140 children from four to ten years old. Individual testwas adopted. The subjects were asked to make comparison of the velocities of twotoycars simultaneously and uniformly moving at the same speed under fourexperimental conditions. After the child had finished each item of the experiment, theexperimenter demanded him to give the reason of his answer no matterwhether the answer was correct or not. In this paper, the experimentalresults are only partly reported. These results indicates that children's abilities tested with theexperimental items have a fair inter-correlation between them, andreactions of the same child to different items show a definite inter-consistency.

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