This document discusses key concepts in history including prehistoric inventions like the wheel and boat, different historical periods from prehistory to modern times, sources used by historians like primary and secondary sources, and other historical concepts like timelines and family trees. The document provides an overview of important elements in studying the past.

1. History
12

2. prehistoric
wheel

4. prehistoric
boat

6. past
what happened

8. present

10. future
what will happen

12. timeline

14. order

16. steamboat

18. prehistory

20. writing

22. ancient
period

24. medieval
period

26. modern
period

28. millenium
millenia

30. primary
historical
sources

32. secondary
historical
sources

34. family tree

36. THE END