Earth’s History — Chapter overview · Earth & Space Science, Grade 9
Use relative order, isotope evidence, and planetary records to reconstruct Earth’s past.
Chapter question
How do we know what happened before people could observe it?
Units in this chapter
- Unit 4.1 · Geologic Time & the Rock Record
I can describe how the geologic time scale organizes Earth's 4.6-billion-year history into eons, eras, and periods.
- Unit 4.2 · Fossils & Relative Dating
I can describe how fossils form and what they reveal about past life.
- Unit 4.3 · Radiometric Dating & Half-Life
I can use parent-isotope fractions to calculate age in a simple closed-system model.
- Unit 4.4 · Reconstructing Early Earth
I can combine several kinds of evidence to explain Earth’s early history.