Historical dynamics is a way of looking at the way that countries, cultures, leaders and events have changed over time. It is like a "history book" that shows us how things have changed from the past to the present. We can look at it and learn about why some things have changed and why others have stayed the same. For example, we can learn about why some countries have changed from being led by a king to having a democracy, or why some cultures have changed their ways of living over time. Historical dynamics can teach us a lot about why societies and the world have changed in certain ways.