Characteristics of the Atmosphere

The atmosphere is a mixture of gases and small amounts of solid that surround the Earth. It is required for life on Earth because it… contains the oxygen we breathe contains the carbon dioxide for plants to “breathe” protects us from the sun’s harmful UV rays The most common liquid in the atmosphere is water. The tiny solid particles include dust, volcanic ash, sea salt, dirt, and smoke…

Nitrogen Nitrogen is the most abundant gas in the atmosphere. It is released into the atmosphere by volcanic eruptions and when dead plants and dead animals decay. About 78% of the atmosphere is made up of nitrogen. Oxygen Oxygen, the second most common gas in the atmosphere, is produced mainly by plants. About 21% of the atmosphere is made up of oxygen. Argon, Carbon Dioxide, Water Vapor, and other gases Argon, Carbon Dioxide, Water Vapor, and other gases make up the remaining 1% of the atmosphere. However, the atmosphere is always changing…it’s composition is effected by every breath we take, car ride we drive, and every plant carrying out photosynthesis

Atmospheric Pressure Air Pressure is the measure of the force with which the air molecules push on a surface. The Earth’s atmosphere is held around it by gravity. The pulling of gravity on the gas molecules in the atmosphere gives them weight. Therefore, they in turn push down on the Earth and it’s inhabitants on the surface. The farther you travel from the surface, the less pressure is pushing down on you. Altitude is the height of an object above the earths surface. As altitude increases pressure decreases!

Air Temperature As you pass through the atmosphere, air temperature changes from warmer to cooler. This is because of how the solar energy is absorbed as it travels through the atmosphere.

Layers of the Atmosphere 4 There are 4 separate layers of the atmosphere. Together as a class we are going to learn what role each layer plays in creating the Earth’s unique atmosphere.

What does it Mean? Exosphere - Thermo – Meso – Strato – Tropo – “Outside” “Heat” “Middle” “Layer” “Change”

Troposphere Lies next to the Earth’s surface, a.k.a. is the lowest layer of the atmosphere. –The troposphere begins at ground level and extends six miles up into the sky where it meets with the second layer. It is the densest layer and contains 90% of the atmosphere’s total mass. This is the layer of the atmosphere you live. It is the layer where all weather occurs. –Meteorologists refer to the troposphere as "The Weather Zone."

Stratosphere It is the next layer above the troposphere. The stratosphere begins at the six-mile point and reaches nearly 31 miles into the sky. It is extremely cold, averaging about -60 o C, and the air is thin. As you move higher in altitude in the stratosphere, the temperature increases because of the ozone layer.

Ozone in the Stratosphere OzoneOzone is a molecule that is made up of 3 oxygen atoms (rather than the 2 oxygen atom molecules we breathe) Just about all of the ozone in the stratosphere is found in the ozone layer Ozone absorbs solar energy (UV radiation). This process warms the air and protects life on Earth’s surface.

Mesosphere The mesosphere is the coldest layer of the atmosphere, temperatures can be as low as -93 o C near the top. The mesosphere begins 32 miles above the Earth's surface. This is where we see "falling stars," which are meteors falling to the earth and burning up in the atmosphere It was recently discovered that this layer is the location of large wind storms reaching 320 km/h

Ionosphere This is the upper part of the mesosphere and lower part of the thermosphere Nitrogen and oxygen atoms absorb solar energy such as x-rays and gamma rays This absorption causes the atoms to become electrically charged into particles called ions It also reflects certain radio waves. For example, when you listen to AM radio the waves are being bounced off the ionosphere and back to Earth’s surface.

Thermosphere The thermosphere is the uppermost layer of the Earth’s atmosphere and begins 50 miles above the Earth. Temperatures in the thermosphere become hotter and hotter when moving farther away from ground level. This is the first layer absorbing the solar radiation and temperatures can be as high as 1,700 o C.