Earth’s Atmosphere

The Air Around You Weather- the condition of Earth’s atmosphere at a particular time Atmosphere- envelope of gases that surrounds the planet

Composition of Atmosphere NitrogenOxygenCarbon Water vapor Trace gases

Oxygen Why do we need Oxygen? Animals Fuels fire Other processes such as oxidization and rusting Ozone- made of 3 oxygen atoms; protects us from UV radiation

Importance of the Atmosphere Supports life Maintains temperature Protects Earth from space debris

Layer’s of Earth’s Atmosphere

Air Pressure

Properties of Air Is air matter? Yes, air is matter because it has mass and takes up space DensityD=M/V Pressure- the force pushing on an area or surface Air pressure can vary from day to day

Measuring Air Pressure A barometer is an instrument used for measuring air pressure Air pressure is measured in inches Two Types: MercuryAneroid

Types of Barometers AneroidMercury

Altitude Affects Altitude, or elevation, is the distance above sea level Air pressure decreases as altitude increases As air pressure decreases, so does its density

Human Impact on Environment Global Warming and Climate Change

Think About It… In what ways do humans impact the environment?

Homework Visit this site and take the survey: php php Record your results How many football fields would it take to support you as an individual? How many worlds would it take if everyone lived the same way?

My Results As an Individual… the land needed to grow all the food, provide materials to make everything they use and wear, and then clean and recycle all the the waste and byproducts of one person - would be the size of 9 football fields all connected together! Considering Everyone… I all six billion people who currently live on our planet had these same living conditions and habits, it would take 3.2 Earths to support us.

Energy in Earth’s Atmosphere

Our Atmosphere How does our atmosphere trap and hold on to heat? Energy from the sun is transmitted to Earth via electromagnetic radiation, which is either: Visible light Non-visible (UV and infrared)

Energy in Earth’s Atmosphere Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface. The rest passes through the atmosphere to the surface.

Energy at Earth’s Surface Greenhouse effect- The process by which heat is trapped in the atmosphere by gases that form a “blanket” around Earth.

Heat Transfer Types of Heat Transfer: Convection-The transfer of thermal energy by the movement of a fluid. Conduction-The direct transfer of thermal energy from one substance to another that it is touching. Radiation- heat you can feel, but cannot see

Climate Change

What Causes Climate Change? Changes in Earth’s position relative to the sun Changes in the sun’s energy output Major volcanic eruptions Movement of continents Human impact

Our Impact While there are many natural reasons for climate change, scientists have found that humans can also have an impact In the last 120 years, the average temperature in the troposphere has risen 0.5 * C Global warming- A gradual increase in the average temperature of Earth’s atmosphere.

The Greenhouse Gases Hypothesis Until the 1800’s, the level of CO 2 in the atmosphere remained the same Think: what significant event in history occurred around this time? Greenhouse gases: gases in the atmosphere that trap energy; ex: methane, CO 2, water vapor

Climate Variation Hypothesis Not all scientists agree with the theory of global warming and believe that climate variation may be a natural and normal occurrence

Effects of Global Warming

Ozone Depletion Ozone in the stratosphere filters out much of the harmful ultraviolet radiation from the sun What do you think ozone depletion means for the environment and for humans?