Experiment 2

The Structure and Properties of Polymers

Graphing Hints

Plots or graphs of data are a very important part of many experiments. A graph is the simplest way to visualize the relationships between the independent and dependent variables. In order to interpret the results of your experiments correctly from the graph, the graph must be drawn correctly. Two examples of graphs are shown below:

Here are some points to always keep in mind when you are making your graphs in this and later experiments.

	Put a brief title at the top to indicate what you are plotting.
	Usually it is a good idea to put the independent variable ( x in this case) along the horizontal axis
	... and the dependent variable ( y) on the vertical axis.
	Indicate the units ( for example, grams or mL) of each variable.
	It is especially important that the distances along an axis have equal values, for example, 2 units per inch.
	If the data show a directly proportional (linear) correlation. Draw the best straight line through the points.
	If the plot is curved, draw the best smooth line through your data points.
	Use as much of the graph paper as possible. Don't squish your plot into a small area.
	Always use a ruler to draw the lines which are supposed to be straight.
	If two, or more, related plots will fit on a graph, use different colors and check the units carefully.