Line Graphs

Line graphs show information as a series of points that are joined up to form a line.  THe line shows a trend or change over time. 

On many of the line graphs you will draw, the horizontal axis will show units of time.  In the example on the left the unit is years.

The vertical axis will show what changes over time.  In the example, the unit is the number of common dolphins.

Plot a series of dots at the points where the information meets.  For example in 1999 there were 6100 dolphins.

Join the dots with a line

Name the vertical and horizontal axes and give the graph a name.

Bar Graphs

Bar graphs show information in the form of a bar or column.  They are useful for comparing quantities.

Select something to compare on the horizontal axis.  In the example on the left different months are compared. 

Select what you are comparing for the vertical axis.  In this example it is the number of severe events for a particular month in the period 1955-1997.

Mark the meeting point of the two pieces of information with a dot and complete each bar.  Make sure the bars are the same width.

Name the vertical and horizontal axis and give the graph a title.

Pie Graphs

In a pie graphthe slices or sectors represent the size of the different parts which make up the whole.  The circle of 360 degrees represents the total or 100% of whatever is being looked at.  The size of the slices is easily seen.  The individual parts or components should be presented in order, from largest to smallest to make it easier to interpret the figures.