ABSTRACT
The first of this group of experiments was planned to demonstrate the development of children’s ability to estimate length and to show whether length was first thought of only in terms of two extremities or even in terms of the most distant point only. The children are shown a short straight wooden stick and a long undulating thread of plasticene. The ends of the plasticene are made to coincide with the ends of the wood and the objects are arranged side by side a few millimetres apart. The children are asked ‘Are they the same length or is one longer than the other?’ If they say they are the same, the children are asked to run their fingers along the stick and the plasticene and the question is then repeated. If they persist in saying they are the same, the question may be put in a form which draws attention to the path of movement. ‘If there were two ants or two little men, and they walked along these lines which would they find longer?’ Finally the ‘snake’ is straightened out upon which children readily admit that the ‘snake’ is now longer; the ‘snake’ is then twisted back to its original shape and the question repeated. The majority of children below 4;6 answered at stage 1. They continued to regard the snake’ and wood as being of the same length when the ends coincided, but the ‘snake’ was thought of as longer when straightened and as returning to the same length as the stick when twisted, i.e. they thought of length in terms of the two end-points only.
