SME
Grade 12 Science · Problem type
The geologic time scale
Use this for “Order the spans of Earth’s history, from Precambrian time to the Cenozoic Era. How long was each?”
Put in order
Put Earth’s history in order, from its formation to today.
1
?
2
?
3
?
4
?
Assumptions
•
The eras are named for their life: Paleozoic means old life, Mesozoic middle and Cenozoic new.
•
The boundaries are dated from ash beds and lava flows by radiometric dating.
•
Earth is about 4,600 million years old.
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