In ScrumProcess, a Sprint burndown chart depicts the total task hours remaining per day.  Ideally the chart burns down to zero by the end of the ScrumSprint.  If your ScrumTeam members are reporting their task hours realistically, the line should bump up and down chaotically.  The chart is often produced by a ScrumWebTool.

The burndown chart is particularly useful for determining when a project will be complete, showing the pace of development offset by EmergentRequirements.

Often the burndown chart will burn up, typically at the beginning of a project or iteration and one must be mindful of ErikTheVikingSyndrome