The Birth of Rocks:
Aren't you glad they don't wear diapers?!
Geologists (people who study earth science) today believe the earth was "born" about 4.5 billion years ago. Then the outer layer of the earth was white hot rock, but it cooled to form the earth's crust. The rock beneath the crust is still extremely hot. Scientists think the temperature is about 13,000 degrees F.! Wow!
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The earth's crust is like a skin. It is a rocky outer layer. We are mainly concerned about the earth's crust because that is where we live and find most of the rocks and minerals that are important to our survival. Minerals are formed from chemicals within the earth. They are solid and inorganic. Which means not alive. A mineral can be composed of just one element, like silver or gold. Or it can be a combination, such as copper combining with oxygen which forms cuprite. |
| Under the crust are three other layers: the mantle, the outer core and the inner core. The mantle goes down about 1,800 miles, and it gets hotter the deeper you go. The outer core is next. It is made up of molten (liquid rock) iron and nickel. The core is at the very center of the planet. It is a ball that is 800 miles thick! It is interesting that, even though it is the hottest rock on the earth, it is solid because of the tremendous pressure from all of the other layers pressing down on it. |  |
All of the layers together form our planet Earth which weighs in at 6.6 sextillion tons. That's one big baby!