Our Living SphereFrom Earth to Space

Scientists divide Earth into four spheres: the LITHOSPHERE, ATMOSPHERE, HYDROSPHERE and BIOSPHERE.

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The Lithosphere

Earth’s solid, rocky outer layer is called the lithosphere.

The lithosphere includes continents and islands. It extends under oceans, on plains and at the tops of mountains. The prefix litho means stone.

The AtmosphereAs you know, the atmosphere is the mixture of gases that surrounds the Earth. The atmosphere includes: Nitrogen 78% Oxygen 21% and other gases 1%

Remember that Carbon Dioxide is less than 1% of our atmosphere!

Water vapor, clouds and solid particles also make up our atmosphere.

The Hydrosphere

Earth’s oceans, rivers, lakes and ice make up the hydrosphere. Oceans cover more than two thirds of the Earth’s surface. The prefix hydro means? ______

The Biosphere*

The biosphere is our “LIVING SPHERE.” Bio means life.

The biosphere is that area on top of, below and above the Earth where life exists. Our atmosphere, lithosphere and hydrosphere all contain living things.

What does biodiversity mean?

Four Layers of the Atmosphere

Do Now For Now What happens to both the air pressure and density inside a weather balloon as it floats higher and higher through our atmosphere?

Atmospheric Density and

Pressure

DescribePressure and

DensityAs you rise through the layers of the atmosphere, both pressure and density decrease. The percentage of N2 (78%) & O2 (21%) remain the same, but there are actually less molecules of everything. This is why it is harder to breathe at higher elevations

Hiking at 14,000 feet tires you out fast.

Climbing at 29,000 feet is almost impossible without bottled O2.

The four layers of Earth’s atmosphere are classified according

to changes in TEMPERATURE!These layers include the

troposphere, stratosphere, mesosphere and thermosphere.

Troposphere!

The TroposphereThe lowest portion of Earth’s atmosphere. The Troposphere actually rests on the Earth’s surface.

Contains 80% of atmosphere’s mass and 99% of it’s water vapor and extends for about 17 km (11 miles).

Tropo means changing: This is where Earth’s weather occurs.

For every 1 km increase in altitude within the troposphere the temperature drops by 6.50 C to a maximum of -600 C at the top of the troposphere.

THE STRATOSPHERE

On top of Troposphere (from 12 to about 50 km – 6 – 30 miles).

Lower Stratosphere temps are around – 600 C.

Weather balloons usually burst in the Stratosphere

Upper Stratosphere temp are warmer due to the OZONE layer. OZONE = three oxygen atoms bonded (O3 ). OZONE absorbs ultraviolet radiation.

Without OZONE?

Without Ozone, more of the sun’s ultraviolet radiation

reaches the planet.

The MesosphereMeso means middle. Starts at 50 km and extends to about 80 km (up to 50 miles above Earth).

Much colder again up to – 800 C.

Meteriods burn in this layer. Shooting Stars!

The Mesosphere protects Earth from being hit by objects from space.

The Thermosphere

Thermo means heat. ( Up to 1,8000 C). The Thermosphere is actually quite hot.

From 80 km and beyond! The air is very thin in this layer. The Thermosphere includes the Ionosphere and the Exosphere. Less and less and less O2 & N2.

Satellites, cell phones and radio waves are found in this layer.

Thermosphere

In the Ionosphere, charged particles from the sun strike O2 and N2 molecules causing the Aurora Borealis or Northern Lights!

CO2 is a Greenhouse

gas!

The Greenhouse Effect

Humans have changed the atmosphere (even slightly) by burning fossil fuels which adds more CO2 to our air.

CO2 along with water vapor and methane trap the sun’s infrared solar energy in the Troposphere which is causing an increase in global temperatures (Global Warming).

The Greenhouse effect combined with OZONE Depletion is causing temperatures to rise on Earth.

Time to Review!

Begin with the crossword puzzle.

Look over your notes, your “Do Nows,” any activities and your textbooks (pages 22, and Chapter 15).

My notes are posted on my calendar.

We have covered Earth’s atmospheric composition and layers, the greenhouse effect and the water, carbon and nitrogen cycles.