Earth’s Changing Atmosphere Chapter 15
Main Idea: Earth’s atmosphere is a mixture of gases that distributes heat and allows life on Earth to exist.
Smaller Ideas: 15.1: Characteristics of Earth’s Atmosphere 15.2: Atmospheric Heating 15.3: Local and Global Winds 15.4: Air Pollution
15.1 Characteristics of Earth’s Atmosphere Atmosphere: Mixture of gases that surround Earth. • Ends at 300 miles about Earth’s surface • Keeps Earth warm • Transports energy
How Thick is Earth’s Atmosphere? Earth: Peach Earth’s Atmosphere: Peach Fuzz
Materials in Earth’s Atmosphere: Recipe for Air: • Nitrogen Gas: 78% • Oxygen Gas: 21% • Argon Gas • Carbon Dioxide • Water Vapor Varies • Other (Inc. solids) Exact amounts of gases can change depending on time of day, location, season…
Characteristics of Earth’s Atmosphere: • Altitude: Height above sea level. Air becomes thinner as altitude increases (fewer gas molecules)
Air Pressure: Force of air molecules pushing on an object. • Density = Mass/Volume Atmosphere’s density decreases as you travel upward. Gravity pulls air molecules toward Earth’s surface.
Lower Air Pressure • Fewer Gas Molecules • Less Density • Higher Air Pressure • More Gas Molecules • Greater Density
Exit Questions: 1. Airplanes fly at the top of the troposphere. Is it more important to heat or cool the passenger cabins?
15.2 Energy from the Sun Heats the Atmosphere All the energy around us comes from the ______.
1 3 2
The Atmosphere Moves Energy From Place to Place • Radiation: Travel of heat energy by electromagnetic waves. • Conduction: Transfer of heat energy by direct contact (touch). • Convection: Transfer of heat energy by the movement of gas or liquid)
Classify the Following as Examples of : Conduction, Convection or Radiation • Transfer of energy by touch. • Transfer of energy by movement of gas or liquid. • Transfer of energy by waves. • Blacktop in the parking lot is warmed by sun. • Air directly above the blacktop gains energy from the warm blacktop.
The bottom of a fry pan becomes hot as it sits on a hot burner. • The sand on the beach burns the bottom of your feet. • The bubbles of goo rise to the top of a lava lamp.