Chemistry is the study of matter and the changes matter undergoes. Matter is anything that has mass and takes up space. The scientific method is a systematic process used to solve scientific problems and involves making observations, developing hypotheses to explain observations, designing experiments to test hypotheses, and developing theories based on experimental evidence. A hypothesis is a proposed explanation for an observation that can be tested in an experiment, where the independent variable is manipulated and the dependent variable is measured. Repeated experimental evidence can lead a hypothesis to become a scientific theory or law.