Timelines use visual indicators (colors, shapes, fonts...) to represent various phenomena.
They help visualize change and continuity by adapting these graphic clues to what the viewer can understand at first glance.
- One can assume that a prolonged line, bar, or arrow of the same colour represents continuity. For example, in a timeline of American presidents, you might see the Franklin D. Roosevelt Administration as a long line from 1933 to 1945 even though there were general elections in the middle, because he was reelected three times after his first term.
- Similarly, change can be represented on a timeline by a difference in colour. To continue with the example of a U.S. presidents timeline, the shift from a Republican to a Democratic president might appear as a shift from a red bar to a blue bar. Moreover, some particular events which caused a major upheaval in history may be symbolized by a little star, a dot, a triangle, or an exclamation mark for example. This could be the case for the fall of the Berlin Wall in 1989 or the dissolution of the Soviet Union in 1991, for instance, because they marked a big change in world history by ending the Cold War.
These indicators help us understand the impact of change in continuity because they appear on the backdrop of a larger portion of history. This enables us to consider them with hindsight, and to see the impact they had on the future.
