Draw a circle around the point to help the reader locate the actual data point. Use a small, dark dot for each data point. Graphs that will appear as a figure in a publication or in a formal laboratory report will not have a title (the information is given in the figure caption).įor hand-drawn graphs in the notebook choose a scale so that the graph fills most, if not all of the page. Avoid the obvious use of “vs.” or “versus” or the word “plotted” in the title. The title should concisely tell the reader what is in the graph. Graphs that will appear in a notebook must also have a title. For example, if our temperature axis has values between 200 and 320 K with each individual point measured to the nearest 0.01 K, we would not write the tick marks as 200.00, 220.00, etc., but rather 200, 220, etc. The number of significant figures in the tick marks is usually less than that in the original data. In this case, you would want to have the value to which you will extrapolate shown on the graph, even though there may be some blank space. The one exception is when you need to extrapolate back to a certain value, but the data are not necessarily close to that value. The key to preparing good graphs is selecting a scale that shows all of the data and minimizes large regions of blank space. For example, if all the x values occur between 400 and 600 nm, a graph of these data could start at 400 nm. Tick mark labels with the last digit being an odd number, other than “5”, are almost never used. If this is not possible, use a scale so that the last digit in the tick mark labels is an even number. For example, if the parameter was temperature and it was measured in Kelvin, then the axis label could be Temperature (K), or Temperature, K or Temperature/K.ĭevise a scale for each axis so that the tick mark labels end in a “0” or a “5”. The axis labels can have one of three formats: parameter name (unit) parameter name, unit parameter name/unit. The axis labels have two parts: the first is the name of the parameter, and the second is the unit. Watch what you say/write as there is only one correct usage!Īll graphs must have axis labels. So if someone says, “volume was plotted as a function of mass” or “the volume is plotted versus mass,” it means that mass was on the x-axis and volume was on the y-axis. We indicate which variable is which by saying as a function of or “versus”, with the dependent variable coming first, and the independent variable coming second. When we prepare a graph the independent variable is always on the “ x-axis”, and the dependent variable is always on the “y-axis”.
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