How Did the Atmosphere Form?

How Did the Atmosphere Form?

How Did the Atmosphere Form?
Reading Level

	edHelper's suggested reading level:	high interest, readability grades 6 to 8
	Flesch-Kincaid grade level:	7.38

Vocabulary

challenging words:

methane, radioactive, argon, radiation, ozone, nitrogen, atmosphere, chlorophyll, ammonia, ultraviolet, billion, helium, gravity, layer, vapor, volcanic

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How Did the Atmosphere Form?
By Patti Hutchison

¹     Did you ever wonder why there was no life when earth began? One reason is that there was no oxygen. Hydrogen and helium were the two gases that made up the earth's early atmosphere.

²     These elements have very small masses. Because of this, they escaped into space. Earth's gravity was not strong enough to hold onto them. The solar wind whipped them away.

³     So, how was our atmosphere formed? You have learned that when a volcano erupts, huge amounts of gases escape. This is called outgassing.

⁴     Much of this gas is water vapor. Carbon dioxide and nitrogen also erupt from volcanoes. Many scientists think the process of outgassing is what formed our early atmosphere.

⁵     The early atmosphere also contained methane and ammonia. These gases probably formed during chemical reactions among the volcanic gases.

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