We know the earth was formed billions of years ago from gases and fiery material (4.5 billion years, to be exact). The earth’s surface might seem cool, stable, and fixed. But underneath the surface, things are always changing. And they’re still red hot!
- The inner core is a huge metal ball, and boy, is it hot! Made mostly of iron, the inner core is 5,000 to 6,000 degrees C. (10,000 degrees Fahrenheit). It’s hot enough to melt metal, but it’s solid. Why? Because the weight of the earth is pushing down on it with so much pressure that it remains solid. Think of taking a ball of loose soil in your hands and pushing on it to make a hard mud ball. The pressure from your hands is similar to this pressure.
- The outer core is a hot liquid made of iron, nickel, sulfur, and oxygen. It’s between 4,000 and 6,000 degrees C. The liquid metal’s movement creates earth’s magnetic field.
- The lower mantle is around 3,000 degrees C. It’s hot enough to melt, but it stays solid because it’s under pressure. It’s made of iron, oxygen, silicone, magnesium, and aluminum.
- The upper mantle is made of two parts. The lower part is a mix of magma and solid rock; the upper mantle is solid rock because it’s closer to the earth’s surface and it’s cooler. It ranges in temperature from 1400 to 3,000 degrees C.
- The crust — the part we can readily see — is solid. Its temperature is about 22 degrees C. (71 degrees F.). The continental crust, or the crust covered with land, is made of granite. The oceanic crust, under the ocean, is made of basalt.
Questions and Answers
Question: How do we know how hot the earth is?
Answer: The truth is, scientists have made their best guesses, but don’t know exactly how hot the center of the earth is. The center of the earth is over 4,000 miles beneath the surface. We’ve only been able to drill 6,000 miles into the earth’s interior. Scientists base their estimates on research and experiments in the lab with the melting temperature of iron under high pressure.
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MLA Style Citation
Declan, Tobin. " How hot is the inside of the Earth? How do we know its temperature? ." Easy Science for Kids, May 2018. Web. 26 May 2018. < http://easyscienceforkids.com/earths-core/ >.
APA Style Citation
Tobin, Declan. (2018). How hot is the inside of the Earth? How do we know its temperature?. Easy Science for Kids. Retrieved from http://easyscienceforkids.com/earths-core/
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