The Atmosphere

The Atmosphere The atmosphere is the layer of gases that surrounds the planet and makes conditions on Earth suitable for living things.

What is the atmosphere? It holds the oxygen you breathe and protects you from the sun’s radiation. It also helps keep us warm.

How does it work?

Layers of the Atmosphere Earth’s atmosphere is divided into several different atmospheric layers extending from Earth’s surface outward.

Layers of the Atmosphere The troposphere is where all the weather occurs. It is the closest layer to Earth’s surface. It is the layer we live in.

Troposphere: Where We Live Densest layer – makes up 90% of the atmosphere’s mass Contains almost all carbon dioxide, water vapor, weather, and life Temps vary greatly

Layers of the Atmosphere The stratosphere is located directly above the troposphere. This is where the ozone layer is.

Stratosphere: Home of the Ozone Temperature rises as altitude rises in this layer because ozone absorbs heat from radiation. Ozone protects the troposphere from harmful ultraviolet radiation.

Layers of the Atmosphere The next layer up is the mesosphere.

Mesosphere: Middle Layer Middle and coldest layer Temp decreases as altitude increases

Ionosphere The Ionosphere is in the upper mesosphere, lower thermosphere. Particles get heated by radiation and become electrically charged. Charged particles are called ions. These particles sometimes radiate energy in the form of light called auroras.

Thermosphere: The Edge Temp increases with altitude Heat is a transfer of thermal energy, but the atoms are so far apart in the thermosphere that no heat is transferred. Although the temperature may be high, it is not hot.

Layers of the Atmosphere Space Exosphere Thermosphere Mesosphere Stratosphere (Ozone Layer) Troposphere (Weather, Life) Earth’s Surface

Names and Their Meaning Sphere = Ball Tropo = turning or change Gasses turn and mix Strato = layer Gasses are layered Meso = middle Middle layer Thermo = heat Temperature is highest

Atmospheric Gases Nitrogen & Oxygen These are the two most common gases found in the atmosphere. They can be found throughout all the layers.

Composition 78% nitrogen (N) 21% oxygen (O) 1% small particles of dust, ash, sea salt, dirt, and smoke

Atmospheric Gases Ozone Ozone is a form of oxygen It is only found in the stratosphere

Atmospheric Gases Water Vapor & Carbon Dioxide (CO2) These are important gases for weather conditions. They are found in the troposphere where weather occurs.

Atmospheric Temperatures Differences in temperature are what separate each layer in the atmosphere from the one above and/or below it.

Atmosphere and Temperature Air temperature changes with altitude. Temperature differences mainly result from the way solar energy is absorbed. Some gasses absorb energy better than others.

Atmospheric Temperatures In the troposphere: As altitude increases, temperature decreases Altitude Temperature

Atmospheric Temperatures In the stratosphere: The stratosphere is cold except in its upper region where ozone is located. Altitude Temperature Ozone Layer

Atmospheric Temperatures In the Mesosphere: This is the COLDEST layer in the atmosphere. Altitude Temperature

Atmospheric Temperatures In the thermosphere: Even though the air is thin in the thermosphere, it is very HOT. Altitude Temperature

Atmospheric Temperatures Altitude Temperature Beyond the thermosphere is the exosphere which leads into outer space where it is very cold, because there is little to no atmosphere to absorb the Sun’s heat energy.

Atmospheric Temperatures Temperature Altitude Outer Space Exosphere Thermosphere Mesosphere Stratosphere Troposphere Earth’s Surface

Altitude, Temperature, and Pressure

Layers of the Atmosphere Thermosphere Mesosphere Stratosphere Troposphere

Water Water can be found in the atmosphere as: Liquid Solid Gas

Air Pressure Air pressure is the measure of the force that air molecules push against a surface. Air pressure is strongest at the surface because there is more air above you. As altitude increases, air pressure decreases. This is because air is less dense the higher up you go.

Exosphere Just past the thermosphere is the exosphere. Very few molecules. The outer most layer.

Review Why does temperature vary from one layer to another? Why does air pressure decrease as altitude increases? Why does the thermosphere have high temperatures but does not feel hot? What two gasses make up most of the atmosphere? What are the layers of the atmosphere, in order from bottom to top?