Students entering physics courses in high school have seen graphs for years in math and science classes, but often do not have a deep understanding of the physical meaning of the graphs. This introductory activity is designed to allow students to collect data for a real world or physical situation (the height versus volume of water held in everyday drinking glasses), and interpret the meaning of the graph and how it describes the physical situation. This activity is well suited for students who don't have much physics knowledge. It uses familiar objects to start developing the skills of making and interpreting graphs and then relating them to the physical situations they analyze. These skills are used heavily all year in our physics classes, which are based on the Modeling Instruction in Physics framework developed at Arizona State University. (Contains 4 figures.)