Line graphs are often used to plot changes in data over time, such as monthly temperature changes or daily changes in stock market prices.
They can also be used to plot data recorded from scientific experiments, such as how a chemical reacts to changing temperature or atmospheric pressure.
Similar to most other graphs, line graphs have a vertical axis and a horizontal axis. If you are plotting changes in data over time, time is plotted along the horizontal or x-axis and your other data, such as rainfall amounts is plotted as individual points along the vertical or y-axis.
When the individual data points are connected by lines, they clearly show changes in your data - such as how a chemical changes with changing atmospheric pressure. You can use these changes to predict future results.
For more information, read the Excel Line Graph Tutorial
This article is one of the "stops" on the Virtual Amazing Race, a lesson plan suitable for grades 5 and up. Students gather research in a webquest of around-the-world topics and (optionally) create a Web site Using PowerPoint.