SynopsisThe viscosities of aqueous solutions of methyl cellulose, dextran, and their carboxymethyl derivatives were measured as functions of molecular weight and concentration. Furthermore, effects of ionic group and added salt on the viscosity of aqueous solutions of carboxymethyl derivatives were investigated. The viscosities of dextran and carboxymethyl dextran solutions did not show any shear stress dependence, but those of methyl and carboxymethyl cellulose solutions strongly depended on shear stress even a t low concentrations. The results were discussed on the basis of the points of molecular structure and hydration and ionic interaction of a polymer chain in solutions.

This paper aims to consider the influence of technique for the children's sensibility by comparison and analysis models made by different constructional way; "tying" and "jointing". As the method, we held a workshop of modeling a "secure house" at 1/20 scale with the third graders of primary school, and they made models with "tying" and "jointing" respectively. After the workshop, the children drew their models with explanations. As the analysis, we morphologically analyzed the models by the floor levels and the structure types, and semantically words with KJ method. As a result, in "tying", as more primitive construction technique, its most important facility was a bed to sleep. On the other hand, in "jointing", as more sophisticated technique, their adventurous sense has increased. That is, the difference of constructive technique evokes the sensual duality of security and adventure.