Atmosphere: Composition, pressure and heat Use these slides as a guide to fill in your atmosphere packet! Answer the questions at the end and do the last page

Mr. Fetch's Earth Science Class The Atmosphere A layer of gas that surrounds Earth. Created long ago by volcanic eruptions. Held around Earth by gravity. Regulates Earth’s temperature. Gravity hold air around Earth A+ Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom

Mr. Fetch's Earth Science Class The Early Atmosphere Much different than our atmosphere today. Not suitable for life: No Oxygen to breathe and no Ozone to protect from sun’s rays. Lots of Carbon Dioxide Very little Oxygen Early Atmosphere Lots of Oxygen More suitable for life on Earth Current Atmosphere Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom

Mr. Fetch's Earth Science Class The path to our current atmosphere Eventually, organisms called Cyanobacteria started making Oxygen photosynthetically. That oxygen was used to create Ozone. Ozone blocked harmful rays from the sun allowing plants to survive on Earth’s surface. Plants produce Oxygen allowing you and I to live and breathe on Earth. Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom

Mr. Fetch's Earth Science Class Composition of the Atmosphere The most abundant gasses in our atmosphere are: Nitrogen Oxygen Argon Carbon Dioxide The atmosphere also contains some solids and liquids: Dust Acids Ash Salt Water Vapor Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom

Mr. Fetch's Earth Science Class Air Pressure Air pressure is the weight of air pushing down from above. As you go up, pressure DECREASES. Air pressure makes air near Earth’s surface DENSE. Mr. Fetch's Earth Science Class Mr. Fetch’s Earth Science Classroom

Energy in the Atmosphere Mr. Fetch’s Earth Science Classroom

Energy in the Atmosphere About 30% of the incoming sunlight is “scattered or reflected,” reflecting light back into space, Scattering is what makes the sky blue, not black! About 70% of incoming sunlight is absorbed by the atmosphere or Earth’s surface, this is used and converted into heat.

Heat and Temperature Heat is a measure of the energy in a system, measured in Joules (J) Temperature is a measure of the average motion between particles (faster = hotter, slower = cooler) When you add the same amount of energy to water (at two different volumes) the resulting temperature is not the same!

Example: The warmth you feel from the sun. Radiation The transfer of heat in the form of waves. Example: The warmth you feel from the sun. Example: Sitting around a campfire. Mr. Fetch’s Earth Science Classroom

Example: A pot touching a hot stove. Conduction The transfer of heat when two objects touch. Example: A pot touching a hot stove. Example: Touching a cold ice cube. Mr. Fetch’s Earth Science Classroom

Example: Heating up water on a stove. Convection The transfer of heat through liquids or gasses. - Warm air rising - Cold air sinking Example: Heating up water on a stove. Example: Heating a room in your house. Mr. Fetch’s Earth Science Classroom

Convection Convection is the main way the atmosphere is heated. Mr. Fetch’s Earth Science Classroom

How our atmosphere is heated. . High-level energy from sun passes right through atmosphere without being absorbed. . Energy is then re-emitted to the atmosphere as “low-level” energy, which is easily trapped and absorbed by the gasses in the atmosphere, thus, causing it to warm up. . This high-level energy is then absorbed by earth’s surface. Mr. Fetch’s Earth Science Classroom