Physical Environment

Big Bang Theory 

  • 13.7 billion years ago n Creation of all matter n Hydrogen and Helium the first n More complex elements evolved through time

The Expanding Universe 

  • The Doppler effect is used to document the expanding universe.

Hubble’s Law 

  • Red shift is related to distance 

  • The farther galaxies are moving faster than the closer galaxies

The Nebular Hypothesis 

  • The solar system formed from a collapsed nebula 1734

  • by Emanuel Swedenborg

  • Observations support this idea

  • the liquid outer core with the Earth’s rotation produces the magnetic field.

The Earth System

  • Earth is a complex system of interacting physical, chemical and biological processes, and provides a natural laboratory whose experiments have been running since the beginning of time.

Earth as a Closed System

  • Exchange of energy but negligible exchange of mass with surroundings

Earth System Science 

  • Earth is a dynamic body with many separate, but highly interacting parts or spheres. 

  • Earth system science studies Earth as a system composed of numerous parts, or subsystems.

Earth System

  • Air

  • Water

  • Land

  • Life

Earth’s Four Spheres

  • Atmosphere - gaseous envelope that surrounds the Earth and constitutes the transition between its and the vacuum of space

  • Geosphere - comprises the solid Earth and includes both Earth’s surface and the various layers of the Earth's interior.

  • Hydrosphere - includes all water on Earth (including surface water and groundwater)

  • Biosphere - the life zone of the Earth and includes all living organisms, and all organic matter that has not yet decomposed. 

  1. Geosphere 

  • is the solid Earth that includes the continental and ocean crust as well the various layers of Earth’s interior.

  • 94% of the Earth is composed of the elements oxygen, silicon, and magnesium. 

Changes occur on the Earth constantly:

  • Molten rock flows from volcanoes 

  • Hurricanes batter beaches and change coastline

  • Earthquakes shake the ground


The average diameter of the Earth is 12,756km


Seismic waves 

  • travel through different material at different rates.

  • When seismic waves change direction or speed, it means they have moved through different layers


3 layers based on Composition

  • Crust 

  • the thinnest layer of the Earth (5-20km thick) made entirely of light elements

  • Primarily Silica plus light metallic elements

  • Mantle

  • makes up 64% of the earth’s mass, (2900km thick) made of rocks of medium density.

  •  Primarily Silica plus iron and magnesium

  • Core 

  • has a radius of 3400km and is composed of the densest elements.

  • Primarily iron and nickel


5 layers based on Physical Properties

  • Lithosphere 

  • Asthenosphere 

  • Mesosphere (mantle) 

  • Outer core 

  • Inner core

Lithosphere

  • is the Earth’s outer layer.

  • Brittle Solid but nearly liquid

Tectonic Plates - It contains the crust and uppermost part of the mantle and is divided into moving sections.

Asthenosphere 

  • is the layer beneath the lithosphere.

  • is the ‘plastic’ solid layer of the Earth that the plates move on top of it.

  • Brittle Solid but nearly liquid

Mesosphere 

  • consists of the lower mantle between the asthenosphere and outer core.

  • contains molten rock which is called ‘magma’.

  • Solid

Outer core

  •  is 2200km thick and made of nickel and iron.

  •  is mostly liquid

  • liquid

 Inner core

  • is a solid sphere of iron, nickel and cobalt (radioactive)

  • The temperature of the inner core is thought to be between 4000 and 5000 degrees Celsius

  • Solid 

  • Scientists believe that cobalt in the core decays producing heat.

  • The heat from the core produces energy that makes the magma move producing earthquakes, volcanoes and plate movement.

Interactions of Geosphere with other Earth System components:

  • Atmosphere - volcanism spews significant amounts of gases into the atmosphere. For example, volcanoes inject large amounts of sulphur dioxide to the upper atmosphere, resulting in global cooling.

  • Hydrosphere: The formation of many minerals involve incorporation or release of water. Also, water speeds up chemical reactions that produce or destroy minerals, and aids in the melting of rock. 

  • Biosphere: Nutrients released from rocks during their breakdown are dissolved in water (to be used by aquatic plants).


Hydrosphere 

  • all the water found on our planet. 

  • Water found on the surface of our planet includes the ocean as well as water from lakes and rivers, streams, and creeks. 

  • Water found under the surface of our planet includes water trapped in the soil and groundwater. 

  • Water found in our atmosphere includes water vapor.

  • Frozen water on our planet includes ice caps and glaciers. 

  • Only about 3% of the water on Earth is “fresh” water, and about 70% of the fresh water is frozen in the form of glacial ice.

  • The hydrosphere includes all water on or near the Earth’s surface.

  • This includes water in the oceans, lakes, rivers, wetlands, polar ice caps, soil, rock layers beneath Earth’s surface, and clouds. 

  • 70% of the Earth’s surface is covered in water.


The Earth’s Water 

  • 97.2% of all of the water on Earth is found in the oceans.

  • Due to the salt content of ocean water, we are unable to use it.

  • Salt water can be cleaned by a process known as desalination.

  • This leaves only 2.8% of the Earth’s water is freshwater 

  • Only 0.8% of which is drinkable

Freshwater Distribution

  • 2.8% of freshwater is divided into: 

  • Glaciers and Ice Caps = 2.15% 

  • Groundwater = 0.62% 

  • Surface Water = 0.03%

Surface Water Distribution

  • 0.03% of surface water is divided into: 

  • Lakes = 0.017% 

  • Soil = 0.005% 

  • Atmosphere = 0.001% 

  • This refers to water vapor in the air 

  • Streams = 0.0001% 

  • The previous percentages referred to all the world’s water but it can be adjusted to reflect percentages based on a 100% scale.


Water Cycles

  • Water constantly moves among the oceans, the atmosphere, the solid Earth, and the biosphere. This unending circulation of Earth’s water supply is the water cycle.

Accumulation - the process in which water pools in large bodies (like oceans, seas and lakes).

Condensation -  the process in which water vapor (a gas) in the air turns into liquid water.

Evaporation - the process in which liquid water becomes water vapor (a gas).

Precipitation - the process in which water (in the form of rain, snow, sleet, or hail) falls from clouds in the sky.

Runoff - the draining away of water (or substances carried in it) from the surface of an area.

Transpiration - the process in which some water within plants evaporates into the atmosphere.


Atmosphere: Water is transferred between the hydrosphere and biosphere by evaporation and precipitation. Energy is also exchanged in this process. Biosphere: Water is necessary for the transport of nutrients and waste products in organisms. Geosphere: Water is the primary agent for the chemical and mechanical breakdown of rock (weathering), to form loose rock fragments and soil, and sculpts the surface of the Earth. Interactions of Hydrosphere with other Earth System components:

Atmosphere - Water is transferred between the hydrosphere and biosphere by evaporation and precipitation. Energy is also exchanged in this process. 

Biosphere - Water is necessary for the transport of nutrients and waste products in organisms. 

Geosphere -  Water is the primary agent for the chemical and mechanical breakdown of rock (weathering), to form loose rock fragments and soil, and sculpts the surface of the Earth.


Earth’s Atmosphere

How our Atmosphere Evolved

  1. The early atmosphere did not support life. It contained deadly gases such as Methane and Ammonia. There was very little Oxygen. 

  2. Over time, gases were added to the atmosphere by volcanic eruptions, and as a result of chemical reactions due to sunlight. 

  3. The OZONE LAYER formed as a result of the chemical reactions. Ozone is made of three oxygen atoms bonded together. It blocks out ultraviolet radiation from the sun. 

  4. The formation of the ozone layer allowed MICRO-ORGANISMS such as Blue-Green Algae to appear on earth. They take in carbon dioxide and release oxygen, so the amount of OXYGEN in the atmosphere steadily increased.

  5. Stromatolites were some of the early organisms that used Photosynthesis to convert CO2 into Oxygen.

*They still exist today and have survived 5 mass extinctions!


Basis for Layers 

  • Layers are based on TEMPERATURE CHANGE within the layer. 

  • As you move up through the troposphere, temperature decreases. 

  • As you move up through stratosphere, temperature increases. 

  • As you move up through the mesosphere, temperature decreases. 

  • As you move up through the thermosphere, temperature increases.

Characteristics of layers 

  • Troposphere - Contains Convection Currents created by the sun’s heat which cause most of our weather. 

  • Stratosphere - Contains the Ozone Layer. 

  • prevents some ultraviolet radiation UV light from reaching Earth’s surface, also where airplanes fly. 

  • Mesosphere - Meteors burn up when they hit this layer. 

  • Thermosphere - Divided into Ionosphere and Exosphere. Satellites & Radio waves travel in this layer. This is the hottest layer

Thermosphere has 2 parts:

  1. Ionosphere (Lower Thermosphere) - Contains electrically charged particles due to absorption of ultraviolet radiation and X-rays that are given off by the sun. Aurora Borealis can be seen in this layer. Radio waves travel easily in this layer. 

  2. Exosphere (Upper thermosphere) - Air is extremely thin. Satellites travel here because there is very little friction with air.


  • Aurora Borealis - A glow in the night sky produced in the upper atmosphere by ionized particles from the solar wind interacting with Earth’s magnetic field.


Transfer of Heat Heat can move in three ways: 

  1.  Conduction-  Heat is transferred through direct contact. 

  2. Convection - Heat is transferred by a hot fluid (gas or liquid) circulating or moving.

  3. Radiation - Heat is transferred by electromagnetic waves.

  • Heat moves throughout (within) our atmosphere in CONVECTION CURRENTS.


The Earth is surrounded by a blanket of air, which we call the atmosphere.


Atmosphere 

  • reaches over 560 kilometers (348 miles) up from the surface of the Earth.

  • is primarily composed of nitrogen (about 78%) and oxygen (about 21%). Other components exist in small quantities.

Troposphere (0-10km) - Climate system that maintains the conditions suitable for life on the planet's surface.

Stratosphere (10-50km) -  contains ozone that protects life on the planet by filtering harmful ultraviolet radiation from the Sun.

Mesosphere, thermosphere, and Exosphere - are zones of diffuse atmospheric components in the far reaches of the atmosphere.


Interactions of Atmosphere with other Earth System components:

Hydrosphere - The gases of the atmosphere readily exchange with those dissolved in water bodies (e.g. oceans, lakes, etc.) 

Biosphere - The atmosphere supplies oxygen and carbon dioxide that form the basis of life processes (photosynthesis and respiration). 

Geosphere - Gases in the atmosphere react with water to produce weak acids that aid in the breakdown of rock.