The construction of graphs is a very important technique in physics. Graphs provide a compact and efficient way of displaying the functional relationship between two parameters and of summarizing experimental results. When graphs are required and if you are instructed to “plot y vs. x” (where x and y are variables), then by convention, y (the dependent variable), should be plotted along the vertical axis (ordinate) and x (the independent variable) should be along the horizontal axis (abscissa).