Unit 1 sets the stage for the rest of the course. We start by exploring the appropriate use of data in science, using significant figures for both measurements and calculations. Density, percent error and temperature conversions are important applications of these skills. Students learn to use dimensional analysis (aka factor-label) in problem solving. We then study the classification of matter, emphasizing both macroscopic descriptions and particle level represenations. We discuss physical and chemical properties and briefly introduce separation methods used in chemistry. Interactive practice is an important study strategy for this course.