Another piece of important information should be included on the bar chart—volume. Volume represents the total amount of trading activity in that market for that day. It is the total number of futures contracts traded during the day or the number of com­mon stock shares that change hands on a given day in the stock market. The volume is recorded by a vertical bar at the bottom of the chart under that day's price bar. A higher volume bar means the volume was heavier for that day. A smaller bar represents lighter volume. A vertical scale along the bottom of the chart is provided to help plot the data, as shown in Figure 3.7.