Rules+for+Good+Graphing

1. ** // Graph on graph paper. // **  2. ** // All graphs should have a margin // ** along the left-hand side and bottom of the page. Axes should be drawn with a ruler along this margin and on an existing line on the graph paper. a. The independent variable should be on the x-axis of your graph (abcissa). b. The dependent variable should be on the y-axis of your graph (ordinate). c. The larger range of data should always be on the longer side of the paper. In other words, adjust the page orientation (portrait or landscape) to accommodate the scales while keeping your variables on the correct axes. 3. ** // Give your graph a descriptive title. // ** The title should explicitly state the dependent variable as a function of the independent variable ( y vs. x). a. Example: Solubility of Salt in Water vs Temperature 4. ** // Label each axis // ** and indicate the units used. The title for the x-axis should be written so that it can be read when the graph is held normally. The y-axis should be written so that it can be read when the graph is rotated 90 °. a. Example: temperature (°C), mass (g) 5. ** // Choose an appropriate scale // ** that allows you to get all data on the graph. Your data should fill approximately 75% of the graph area. The divisions of the graph should be part of an easily identified series. Use your largest and smallest values in your data to get the range; divide by the lines available and round up to the nearest common number. For most graphs there is no need to begin the scale at zero. 6. ** // Plot your data. // ** Points should be just visible and circled. Ideally, the diameter should indicate the error margin. If more than one set of data points are being drawn on the same graph, different shapes may be used. A key on the graph should explain these symbols. 7. ** // Draw a smooth curve or straight line // ** to represent the general tendency of the data points. In a laboratory experiment, there will always be some error. This means that the points you get may have some variation, some may be a little high or a little low. Never simply connect the points. The idea is to fit a line or curve that best shows the relationship despite experimental error.
 * Rules for Good Graphing **