Earth’s Changing Atmosphere Earth’s Atmosphere Supports Life Lesson 2

ATMOSPHERE BIOGRAPHY VIDEO https://www.youtube.com/v/1YAOT92wuD8

The atmosphere makes life on Earth possible The atmosphere is a whole layer of air that surrounds Earth which supports and protects life in several ways: Absorbs harmful radiation Maintains Earth’s temperatures Provides elements essential for life

Characteristics of the Atmosphere The atmosphere has chemical and physical properties The density of the atmosphere decreases with altitude Altitude is the distance above sea level Density is the amount of mass in a given volume of a substance (the thickness or thinness of air) The decrease of density with greater altitude means that most of the mass of the atmosphere is close to Earth’s surface

Materials in the Atmosphere Most of the materials in the atmosphere are gases (Nitrogen 78%; oxygen gas 21%; Argon, carbon dioxide and other gases 1%) Nitrogen: promotes plant growth Oxygen: needed for animals & plants to perform life processes Carbon dioxide: plants use it to make food Other tiny particles of solid or liquid materials include: dust, sea salt, and water droplets exist in the atmosphere

Nitrogen gas is the major component of the atmosphere Carbon dioxide plays a large role in global warming (burning of fossil fuels) Ozone gas only makes up a small layer of the atmosphere and protects the surface of the Earth from excessive UV radiation.

Atmosphere Fact Sheet Layers Troposphere Stratosphere Mesosphere   Temp. Range Location Width (in miles) Inside Layer Other Fact Layers Troposphere Stratosphere Mesosphere Thermosphere Exosphere

Earth is heated unevenly by the Sun At the poles, the Sun’s rays strike the Earth’s surface at a much greater angle (less heat and energy are absorbed)