The interval between the gridlines in an Excel chart is typically blank, but you can highlight the intervals using an alternating pattern by changing the formatting for the gridlines themselves ...

Learn about line graphs with this BBC Bitesize Maths article. ... Draw the vertical scale and number it in regular intervals. In this example, the scale is increasing in increments of one hour.

To understand what a time graph is showing you, you need to look at three things: 1. Title - The title tells you what the graph is about. For example, "Temperature on the First of September." 2.