What is Earth Science? Earth science is the branch of science dealing with the constitution of Earth and its atmosphere How is Earth Science Different? Earth science has a global perspective, especially when it is studied using a systems approach Earth science draws from all the other sciences including physics, chemistry, biology, meteorology, and astronomy Earth science requires consideration of time. It deals with sequences of events, causes and effects and time in terms of millions or billions of years. How Does Earth Science Relate to Other Sciences Biology: study of plants, animals and their interactions with the environment Chemistry: the atomic nature of rocks, minerals, and living organisms Physics: description of movement within systems, forces at work Astronomy: formation, composition, and movement of the planets
The Branches of Earth Science Pre-Instruction Guesswork Match the branch of Earth science with its study 1. Meteorology 2. Seismology 3. Geology 4. Petrology 5. Astronomy 6. Oceanography 7. Hydrology 8. Volcanology I. Properties of Earth s water and its movement II. Celestial objects, space, and the physical universe as a whole III. Earthquakes and related phenomena IV. Volcanoes V. Physical and biological properties of the sea VI. Earth s physical structure, history, and processes VII. Processes and phenomena of the atmosphere / weather VIII. Origin, structure and composition of rocks
Major Branches Astronomy (celestial objects, space, and the physical universe as a whole) Geology (earth's physical structure, history and processes) Oceanography (physical and biological properties of the sea) Meteorology (processes and phenomena the atmosphere / weather) Minor Branches Crystallography (structure and properties of crystals) Geomorphology (physical features of the surface of the earth and their relation to its geological structures) Hydrology (properties of the earth's water and its movement) Mineralogy (study of minerals) Paleontology (fossil animals and plants) Petrology (origin, structure and composition of rocks) Seismology (earthquakes and related phenomena) Stratigraphy (order and relative position of rock layers / strata) Volcanology (volcanoes) Sedimentology (modern sediments and process of deposition) The Big Bang Theory / Solar Nebula Hypothesis 1) What were early thoughts about the universe? 2) Where did the idea of a starting point for the universe come from? 3) Why is the Big Bang Theory a problematic name? 4) Why are we uncertain about the time when the Big Bang occurred? 5) In your own words, describe the Big Bang Theory.
The Big Bang Theory we live in an expanding universe, that originated from a compressed energy/matter source in a very simple sense, all matter, energy and forces were compressed and over time expanded and changed into the universe as we know it the Big Bang has been tested to the point where it is generally accepted the Big Bang theory deals with the universe as a whole The Nebula Hypothesis deals specifically with our solar system and is an extension of the Big Bang Theory Solar Nebula Hypothesis 5 billion years ago a nebula (cloud of dust & gas) began to contract & pull inward as it contracted, it began to rotate the rotation caused flattening & faster rotation the middle settled into a hot dense protosun the remaining material settled into rings and some compressed into protoplanets planets near the sun should be small and rocky planets further should be large and gaseous this theory explains the formation of the basic parts of planets only (geosphere formation) atmospheres, hydrospheres, and biospheres come later Formation of Earth
Contrast the structure of the malt candy and apple shown. Malt Candy Apple when Earth first formed, it was a homogeneous mixture of materials the interior of Earth began to melt due to: heat from natural radioactive decay heat and pressure from asteroid & meteor collisions the melting allowed material to flow & settle based on density light materials (silicon, oxygen, aluminum, etc) are found in the crust dense materials (iron, nickel, etc) are found in the core this melting process may still be occurring today
Layers of Earth The Crust the outer layer (5-70 km thick) continental crust is mainly felsic (light coloured igneous rock) oceanic crust is mainly mafic (dark coloured igneous rock) the lithosphere is the crust & the upper part of the mantle (around 100 km) The Mantle thick (2880 km) semi-solid rock similar to peridotite (very dark igneous rock) the upper part is the asthenosphere this is a hot layer that moves plates due to convection currents The Core the outer core (2240 km) is molten iron & nickel believed to be liquid (s-waves cannot pass through it) the inner core (1280 km) is believed to be solid iron & nickel extremely high pressure & density Compositional Viewpoint (what it's made of) crust mantle core
Mechanical Viewpoint (structure) lithosphere (brittle / solid) asthenosphere (semi-solid) lower mantle (solid) outer core (liquid) inner core (solid) both viewpoints are often used in conjunction depending on what the goal is 1) Draw and label Earth's layers Quick Review 2) Which layers are considered liquid? 3) Which layer has the greatest pressure? 4) Which layer has the lowest temperatures? 5) How is Earth like an apple? 6) Callisto, a moon of Jupiter, has a solid, homogeneous interior covered in a thin layer of what may be ice and water. What was different about the formation of Earth and Callisto?
Four Main Systems Hydrosphere Atmosphere Geosphere Biosphere a system is made up of interacting parts that make up a complex whole the four systems work together to operate Earth in a beneficial way similar to the human body, if one system becomes damaged all systems suffer How have you interacted with the four spheres today? Geosphere Biosphere Hydrosphere Atmosphere How could each event impact each of the four spheres? 1) Forest fire 3) Volcanic Eruption 2) Flood 4) Hydroelectric Dam Details on Spheres Hydrosphere 71% of Earth's surface is covered in water this includes glaciers, ponds, rivers, groundwater and oceans
97% of the hydrosphere is ocean water changes through the water cycle (dynamic) Atmosphere thin, when compared to Earth's thickness a blanket of air around Earth providing oxygen (and other necessary gasses) and protection for UV radiation location of weather oxygen - carbon dioxide cycle (dynamic) Geosphere thought of as rocks, but also contains minerals and inner-earth materials the geosphere is forever changing due to plate tectonics and mantle convection (dynamic) Biosphere all living organisms and their interactions nutrients travel through food chains and are recycled through decomposition (dynamic) Dynamic Earth Earth is in a continuous state of change Examples: