This UNESCO newsletter is divided into these three sections: (1) a student chapter on the rates of chemical reactions; (2) the student laboratory guide; and (3) the teacher laboratory guide. The laboratory guides describe 14 experiments showing students the differences in chemical reactions and how the rate can be affected by temperature, concentration or catalysts. In the student's guide each experiment is introduced by a short outline followed by a description of the procedure in detail. Important points concerning the principles on which the experiment is based, including explanation of relevant general background, are given in the "discussion" of each experiment. Each experiment is followed by examples of questions which could help the teacher in the classroom; answers, with the explanation in detail, are summarized in the teachers' guide. (Author/PR)