This research aims to produce the valid teaching materials. The teaching materials are developed using POE model to increase students’ critical thinking skills in junior high school on pressure topic. The teaching materials developed consist of the lesson plan, student worksheet, student book, the critical thinking skills test, and concept mastery test. The five indicators of critical thinking skills measured in this study are providing simple explanations, the ability to give reasons, make conclusions, make and determine the results of considerations based on the application of facts, and choose alternative solutions. Model of teaching materials development usedthis research is 4D model. Validityxdataxwere obtainedxfrom thexvalidationxbyxexperts usingxthexvalidityxinstrument. Thevvdatavvobtainedvvwerevvanalyzed descriptively quantitatively basedxonxthe validity criteriaxof teaching materials. Basedxonxthe assessmentxofxthreexvalidators, the developedxteachingxmaterials had very valid category.

Keywords : Validity,xteachingxmaterials, POE, pressure topic, criticalxthinkingxskills,xconceptxmastery.