Please enable JavaScript.
Coggle requires JavaScript to display documents.
How Do We Know How Old Rocks Are? - Coggle Diagram
How Do We Know How Old Rocks Are?
Conclusion
I really didn't know anything about how we know the age of rocks before this. I also didn't know that radiometric dating was a thing and I found the half-life of molecules very interesting.
I learned a lot about myself as a reader after I read this because I thought I wouldn't like it since it was sort of science fiction but I really enjoyed it.
Claim
We know how old rocks are by observing the differences between layers and by using radiometric dating. We can learn a lot about the earth's past by doing this.
My connection is to the first book of the Lorien Legacies series, I Am Number Four. In this book, John Smith is the fourth member of nine aliens hiding on earth to survive. After the Mogadorians destroyed their planet, they were protected by a spell so they could only be killed in the order of their numbers. John is hiding and waiting for his powers to develop so he can finally start to fight back finally.
Resources
Rock Cross-Section- Page 40
Edible Radiometric Dating- Page 41
Rock Ages- Page 39
Cosmos Clean Room- Page 36
Evidence 2: How We Know the Exact Age of Rocks
We can figure out the exact age of rocks by using radiometric dating. This is where we date a rock by figuring out how fast it is radioactively decaying. The half-life is the average time it takes for half of the atoms to decay. Once we know the half-life of something, we measure how much radioactive material is left to figure it's exact age.
One specific event that I remember is when John first meets Sarah. He is very surprised and nervous. It's the first interesting thing in the story that isn't just background information. This is the beginning of a very important relationship that carries throughout the series affecting much of the main plot. I think that it is the exact point where I became invested in the story.
Evidence 1: How We Esimate the Age of Rocks
In I am Number Four, most of the beginning is John trying to fit in at another new school. The middle mostly consists of John trying to maintain and further the trust between him and his newfound friends while learning to fight. In the end, there is a climactic battle where some unexpected friends show up, but tragedy also strikes.
We can estimate the age of rocks through relative dating. This includes stratigraphy or looking at the differences between layers. You can also use the principle of original superposition, or the idea that older layers are below the younger ones. Faults, fossils, and cross-cutting relationships are all also good ways to get a general idea of the age of a rock.
Evidence 3: Why Do We Need To Know
I think this story is valuable because there are strong themes of love friendship, family, love, loyalty, and staying true to word. There are a lot of questions about how you decide what to do in the face of evil or what you are supposed to do when you lose someone. It's the first book/book series that has made me feel such loss since the Fault in Our Stars.
We need to know how old rocks are because they can tell us a lot about the past (What lived before us, geography, etc.). Figuring out the age of rocks also helped us finally answer the question of the earth's exact age. This changed many things in science and helps us continue to move forward in our understanding of everything.