This study aims to analyze student outcomes after learning the acid-base concept supported by PhET Simulation. The PhET simulation is used to help visualize sub-microscopic representation of the acid base solution. The method used is one group pre-test and post-test design with the subject this study consists of thirty high school students in the Bandung area. The research instrument used was a test that measured the ability to distinguish the strength of acid-base at the level of sub-microscopic representation, calculate the degree of ionization, the relationship of Ka to concentration, and analyze the pH of the solution. The result of this study it can be concluded that the PhET simulation can improve student learning outcomes to the level sub-microscopic representation.

<p>A research has been conducted which aims to design a waste-based calorimeter as an alternative to measuring heat for chemistry practicum in schools. Research products developed through the steps of design-based research comprising the steps of analysis, design, and development. The resulting product is a waste-based calorimeter equipped with an automatic stirrer. The container to store the reagent solution on the calorimeter is made of Styrofoam, paper, plastic, melamine, PVC and bamboo. Optimization tool was conducted to determine the heat capacity of the calorimeter and the enthalpy of neutralization. The highest accuracy calorimeter value between 78-97%. Bamboo calorimeter has the highest accuracy value (97%). Styrofoam calorimeter has the lowest accuracy values (78%). Based on the results of the validation and feasibility test it can be concluded that the product is declared valid and feasible.</p>