Scientists who study the ancient Earth have been working for hundreds of years to build an accurate timeline of the formation of the planet and the evolution of all life. This is no simple task! In order to build and improve this timeline, scientists must have several types of accurate methods they can use to determine the ages of materials. There are two main categories by which they do this: relative age dating and absolute age dating.
Relative Age
Relative age is the age of rocks and fossils compared to the ages of other rocks and fossils. Imagine it this way: If you have any siblings, using relative age dating would be like saying, 'I am older than my brother but younger than my sister,' but using absolute age dating would be like saying, 'I am 12 years old.'
Put these people in order from youngest to oldest:
Congratulations you understand relative age!
Unlike people, you can’t really guess the age of a rock from looking at it. Yet, you’ve heard the news: Earth is 4.6 billion years old. Dinosaurs disappeared about 65 million years ago. How do scientists actually know these ages? We will continue to answer this question as we further explore this module.
Relative Age vs. Absolute Age
Relative age provides an approximate age
Absolute age provides an exact age in years.
Absolute age provides an exact age in years.
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Topic Tips
- Relative age determines the approximate age of rocks and fossils compared to other rock layers and fossils.