Earth's Atmosphere and Layers

• Earth's atmosphere is about 78% nitrogen, 21% oxygen, and 1% other gases.
• The atmosphere is composed of 5 main layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere.
• The atmosphere protects life by shielding it from UV radiation.
• The atmosphere keeps the planet warm through insulation.
• The atmosphere prevents extremes between day and night temperatures.
• The sun heats layers of the atmosphere, causing convection, which drives air movement and weather patterns.

Layers of the Atmosphere

• The exosphere is the last and thinnest layer, extending to 10,000 km above Earth's surface.
• The thermosphere has very thin air and extremely hot temperatures.
• The mesosphere extends 50 miles beyond the stratosphere and is where most meteors burn up.
• The coldest place on Earth is at the top of the mesosphere.
• The stratosphere extends 32 miles after the troposphere.
• The stratosphere gets heat from the Ozone Layer absorbing radiation, so it gets warmer further from Earth.
• Weather balloons can reach into the stratosphere.
• The troposphere is closest to the ground, around 30,000-50,000 feet high, and where we live and planes fly.
• About 80% of the atmosphere's mass is in the troposphere, which is heated by Earth's surface.

Water Cycle

• The water cycle is the continuous movement of water between the atmosphere, land, oceans, and living things.
• The water cycle is driven by the Sun’s energy/heat.
• Sublimation is the change of state from a solid directly to a gas.
• Transpiration is the process by which plants release water vapor into the air through leaves or stems.
• Evaporation is the change of state from a liquid to a gas, usually at the surface of liquid water.
• Condensation is the change of state from a gas to a liquid.
• Precipitation is any form of water that falls to Earth’s surface from clouds.
• Deposition is the change of state from a gas directly to a solid.
• Infiltration is the process by which water on the ground enters the soil.
• Runoff is precipitation that flows over the land and into streams and rivers.

Vocabulary

• Wind is the natural movement of air caused by differences in density.
• Convection is the movement of matter due to differences in density and the transfer of energy due to the movement of matter.
• A convection cell is a distinct volume of circulating fluid in a fluid medium under gravity, usually found in large groupings.
• The Coriolis effect is the curving of a moving object's path due to Earth’s rotation, affecting weather patterns and ocean currents.
• The Coriolis effect makes storms swirl clockwise in the Southern Hemisphere and counterclockwise in the Northern Hemisphere.
• Global winds are the main belts of wind that move in particular directions across the Earth.
• Density is mass per unit volume, indicating the compactness of a substance.
• Salinity is the amount of salt in water.
• Ocean currents are movements of ocean water following a regular pattern.
• Forces that act upon ocean currents include wind, the Coriolis effect, breaking waves, continental deflection, tides, and temperature and salinity differences.
• Surface currents are driven by global wind systems fueled by solar energy.
• Surface currents transfer heat from the tropics to the polar regions, influencing climate.
• Deep ocean currents are driven by density and temperature gradients, known as thermohaline circulation or the ocean's conveyor belt.
• Ocean currents are the continuous, predictable, directional movement of seawater driven by gravity, wind, and water density.
• Ocean water moves horizontally as currents and vertically as upwellings or downwellings.
• Ocean currents are responsible for the transfer of heat and thus impact Earth’s climate system.
• Halocline refers to a division of water based on differences in salinity.
• Thermocline refers to a division of water based on differences in temperature.
• Gyres are large systems of rotating ocean currents, with five major gyres where the Great Pacific Garbage Patch is located.
• The Great Ocean Conveyor Belt is a system where water moves between cold depths and warm surfaces in oceans, also called thermohaline circulation.
• Estuaries are where fresh river water mixes with ocean water, supporting lots of biodiversity.
• Ocean circulation is the worldwide movement of water (currents) in the oceans.