What is plate tectonics? Earthquakes and volcanoes
Plate tectonics: The world as seen from space (flattened out) The continents move around When you look at a map of the world, it seems as though it was always [...]
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09, 2017
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06, 2017
What causes volcanoes? Geology
Volcano erupting Volcanoes are places where the plates of the Earth's surface have cracks in them, so that the very hot melted rocks that are under the tectonic plates bubble [...]
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06, 2017
What is salt made of? Geology
Evaporated sea salt Salt molecules are a combination of chlorine atoms and sodium atoms. These atoms mix together easily and, once they are mixed, the salt molecule is very stable [...]
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06, 2017
What are sedimentary rocks? Shale and limestone
Sedimentary rocks: Limestone cliffs in Saudi Arabia Before sedimentary rocks When the Earth was first forming, about six billion years ago, there weren't any sedimentary or metamorphic rocks. The only [...]
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06, 2017
What is erosion? Geology
Erosion of a cliff in Canada Igneous rocks came first When the Earth first formed, about four and a half billion years ago, it was all liquid rock and liquid [...]
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06, 2017
What is jade? Metamorphic rock
What is jade? Jade rock from Alaska Jadeite and nephrite Jade is really two kinds of metamorphic rock, jadeite and nephrite, that look pretty much exactly the same. Scientists can [...]
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06, 2017
What is metamorphic rock? Marble, slate, diamonds
What is metamorphic rock? Slate rocks in Cascadilla Gorge, Ithaca, New York Metamorphic rocks form under pressure About 450 million years ago, some of the sedimentary rocks began to transform [...]
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06, 2017
Different kinds of rocks
Granite rock There are three different kinds of rocks on Earth, and they form in very different ways. The first kind is igneous rock, which means "fire rocks". Igneous rocks [...]
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06, 2017
What is quartz? Igneous rock
What is quartz? A chunk of white quartz What is quartz made of? Quartz is an igneous rock made out of molecules of silicon and oxygen atoms held together in [...]
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06, 2017
What are igneous rocks? Volcanic stone
Igneous rocks: Obsidian tools What does "igneous" mean? Igneous means "fiery", and igneous rocks are rocks that were made by heating them up in a fire. Usually that fire is [...]
