Earth Science
The major units of study in earth science this year include the water cycle, weathering and erosion, tectonic plate movement and changes of the Earth over time. As we examine how the Earth's resources form and are changed over time, we will see how they are important to humans and all of the natural world.
Geologic History of the Earth
Are all fossils about the same age? Let's examine how scientists have learned about the age of our planet Earth and how changes over time have helped us figure out the secrets of the ages. Learn about different laws that govern our thinking and assumptions we make to understand the geologic history of our Earth.
Click here to start your understanding of the Law of Original Horizontality. This law says that sediments are deposited in horizontal layers due to gravity. Sediments form sedimentary rock in horizontal beds via water or wind because gravity settles them that way.
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Click here to continue your learning about the history of the Earth using the Law of Superposition. Remember the prefix "super" means above. The newer layers of rock are found above the positions of the older rock layers.
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Click here to examine the different laws of relative rock dating. Remember, this method of dating or finding the age of rocks is in relative terms, not actual numbers.
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Click here to learn about how radiocarbon dating works. Maybe in social studies you have heard of carbon dating as a method to find out how old a mummy is or other ancient artifacts. This briefly explains how this is done.
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Click here to go a bit more in-depth on the subject of determining the more precise age of fossils.
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Click here to see how carbon dating and examining layers of rock in different locations can make the puzzle of "how old is the Earth" even more complex. This is a good video to help you with Do 3.
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BONUS! How is the Law of Superposition used in studying bodies in space? Click here to check out some images of the moons of the planet Jupiter. Look at the image seen here on the left. Which crack in the ice happened last? Which crack happened before that one?
Geologic Time Scale
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