DO NOW: COPY THIS IN COMP BOOK Objectives: Describe the Earth’s atmosphere. Identify three methods of heat transfer. Explain the greenhouse effect. Key Terms: Ozone Radiation Conduction Convection Greenhouse Effect

Key Terms Ozone Radiation Conduction Convection Greenhouse Effect

The Atmosphere Mixture of gases that surround Earth. Gases can be added to and removed through: living organisms volcanic eruptions

The Atmosphere Insulates Earth’s surface. Regulates Earth’s temperature allowing living organisms to survive.

Composition of the Atmosphere N2 – Most abundant gas from volcanoes and decay. O2 – Second most abundant gas mostly by plants.

Composition of the Atmosphere Other gases argon carbon dioxide methane water vapor Also contains particulates.

Air Pressure in Atmosphere Atmosphere is denser near the Earth’s surface due to gravity.

Layers of the Atmosphere Troposphere Stratosphere Mesosphere Thermosphere

Layers of the Atmosphere

Troposphere Temperature drops as altitude increases. Weather conditions exist here Most dense layer

Stratosphere Above troposphere Temperature drops as altitude increases Ozone layer is contained in stratosphere.

Stratosphere - Ozone Ozone = O3. Absorbs UV radiation Reduces radiation that reaches Earth. UV radiation damages cells.

Mesosphere Above the stratosphere. Coldest layer of atmosphere Temperatures can reach –93ºC.

Thermosphere N2 and O2 absorb solar radiation 2,000+ ºC. Atoms become charged (ions) Lower layer - ionosphere Ions radiate energy as light (Northern Lights) Least dense layer

Northern Lights

Layer of the Atmosphere Graphic Organizer Layer of the Atmosphere Characteristics

Energy Transfer in the Atmosphere Radiation - energy transferred directly through space. Example: Sunlight

Energy Transfer in the Atmosphere Conduction - energy transferred as heat through a material. Example: spoon in a cup of soup

Energy Transfer in the Atmosphere Convection - movement of matter due to differences in temperature results in transfer of energy as heat.

The Movement of Energy in the Atmosphere Air currents - caused by differences in temperature (density) in atmosphere. The continual cycling of warm/cool air (or water) = convection current.

Energy Transfer in the Atmosphere

Heating of the Atmosphere Solar energy reaches Earth as electromagnetic radiation

Heating of the Atmosphere Oceans and land radiate absorbed energy back into the atmosphere. Dark objects absorb more solar radiation than light objects.

Greenhouse Effect Sunlight penetrates atmosphere (warms surface of Earth). Greenhouse gases (CO2, methane, and nitrous oxide) and water vapor absorb some radiation (rest is lost to space). Causes warming of the surface and lower atmosphere of Earth Necessary for life to exist.