Science museums always strive to anticipate the actions of visitors in designing hands-on exhibitions for the museum. This helps to improve the learning process for these visitors, especially for the children among them. Hands-on exhibitions are particular effective for teaching children because they involve principles derived directly from Piaget's developmental psychology. Thus they have become an important part of exhibition planning for children in science museums. This article deals mostly with how children interact with hands-on exhibitions. The target visitors for the area studied-the Children's World of Science section of the NSTM-includes pre-schoolers and lower primary school students, i.e., children from about four to eight years old. Three aspects are examined: the liveliness of interaction, what physical skills are involved, and what intellectual stimulation is provided. Involvement of other family members is also examined. A study of 78 subjects yielded several results: the typical group of visitors was a female adult accompanied by one or two children, with the children being the principal participants in the exhibits. The main items of interest for the children were things that they liked and were fully capable of using. The adult's role was mostly to help the children interact with the exhibits and to maintain order in going through the exhibit. Neither adults nor children showed much interest at all in the panels of the exhibitions. In addition, analysis 0f the three types of hands-on exhibitions revealed two factors which were instrumental in the amount of interest in and time spent on certain items in exhibitions: first, how much interaction among the visitors themselves was generated; and second, the effects on the visitors after the period of interaction was over.