ESCI-LESSONS-1-5.pdf

Q1 esci lesson 1: the universe Georges Lemaître  The main proponent of The Big Bang  IA Belgian priest and astronomer who first proposed the idea of an expanding universe, which laid the groundwork for the Big Bang theory in the 1920s.  He is a Briti...

Q1 esci lesson 1: the universe Georges Lemaître  The main proponent of The Big Bang  IA Belgian priest and astronomer who first proposed the idea of an expanding universe, which laid the groundwork for the Big Bang theory in the 1920s.  He is a British civil engineer, physicist, and cosmologist The Big Bang  13.7 billion years ago, all matter & energy concentrated into an infinitely small dense point called the singularity.  Matter reacted with antimatter, and they annihilated each other. This is where time began.  An incomprehensively large explosion sent all matter of the universe flying outward, expanding at incredible speeds Key Points of The Big Bang  The first explosion or the “Bang” happened 13.7 billion years ago when matter and anti-matter reacted and formed a singularity  The Big Bang event is divided into two (2) eras which are in turn divided into epochs  The universe continues to expand as stars continue to form other elements from hydrogen in the process called nuclear fusion.  The earth began to form 5 billion years ago Radiation Era  concentrated on the formation of stable nuclei. Matter Era  is the time which stable elements come together to form matter. It is the most extensive of the two eras. The Solar Nebular Hypothesis  The birth of our solar system began as dust and gases (nebula) started to gravitationally collapse.  The nebula contracted into a rotating disk that was heated by the conversion of gravitational energy into thermal energy.  Cooling of the nebular cloud caused rocky and metallic material to condense into tiny particles.  Repeated collisions caused the dustsize particles to gradually coalesce into asteroid-size bodies. Within a few million years these bodies accreted into the planets. Key Points of the Solar Nebular Hypothesis  The sun, after becoming a star, has gained gravity and attracted heavier atoms around it, forming a nebular cloud  Since gravitational pull is strongest near the sun, heavier atoms and elements fused together and formed the terrestrial planets: (1) Mercury, (2) Venus, (3) Earth, and (4) Mars  Less dense atoms combined and formed the outer or Jovian planers: (1) Jupiter, (2) Saturn, (3) Uranus, and (4) Neptune  The so called “asteroid belt” separates the terrestrial and Jovian planets. “Kuiper Belt” is located after the Jovian Planets. “Oort Cloud” – icy debris and edge of the Solar System  15 "Goldilocks" Factors that Allow Life on Earth to Exist 1. Proximity to the Sun allowing liquid water.  This is essentially the greens-fee for any form of life in the universe. 2. The size and composition of Earth as a Rocky Planet  The current science indicates that a rocky planet offers the best foundation for life and especially the diversity of life.  The density of planet Earth makes it stable in its orbit. The possibility of the loss of gravitational attraction between Earth and Sun is very low. 3. Stability of Earth's atmosphere and chemical composition.  An atmosphere is critical to life whether it be a gaseous atmosphere on the surface of the planet, or a saturated atmosphere. The chemical composition and density are also important.  Our atmosphere is rich in Nitrogen, Carbon Dioxide, Oxygen and other compounds that create a benign atmospheric combination. 4. The Magnetosphere.  The fact that Earth has a metallic, molten core (outer) creates a magnetic field around the planet called the Magnetosphere.  This invisible "gravity shield" deflects radiation from the sun and space and protects organisms on the planet from the solar wind. 5. Consistency of Temperatures on Earth  The average temperature on Earth not only allows liquid water to exist but also provides a relatively stable environment for organisms.  Earth is not too cold or too hot, it's just right. Temperature extremes limit the diversity of biological life forms, and while some bacteria can survive extremes, advanced organisms typically are too complex to endure the extremes. 6. Diversity of Life.  The Diversity of life on Earth has two unique advantages. For one it creates a food-chain that can sustain a variety of species  The diversity of life on Earth may be the only reason life on Earth has continued after the extinction of 65% of all living dinosaurs. 7. Earth's moon.  The moon has a remarkable, stabilizing effect on our planet. It has slowed us down to 24 hours and has also stabilized Earth's rotation on its axis.  The moon also creates tides which is an evolution machine in the tide-pools and tidal-zone between land and sea.  This repeated tidal action is thought to have encouraged evolution for animals. 8. Stability of the Sun as a star.  Our sun is actually a very average star in terms of size and activity. That means the radiant heat and radiation are typically consistent.  Our sun is also a solitary star. It's believed that 85% of stars in the Milky Way are binary stars. 9. The Ozone Layer.  Ozone is much like the Magnetosphere. It's another buffer against solar radiation especially Ultra-violet (UV) radiation  This is a result of our dense and complex atmosphere. 10. The amount of water on earth.  Water on a planet is a great way to give life a head start.  The water on earth was largely due to icy, comet collisions during the late heavy-bombardment 3.3 to 4.5 million years ago. The result was essentially a water planet with less land than sea. 11. Jupiter as a Solar System vacuum cleaner.  It’s immense gravitational field acts like a system-wide vacuum cleaner attracting rogue asteroids, comets and meteors to its surface and away from other planets including Earth. 12. The stability of the solar system.  4.5 million years ago, our Solar System was a highly unstable environment  Fortunately, our present Solar System is relatively stabilized in terms of planetary orbits. 13. Our location in the Milky Way Galaxy  Our location in the Galaxy is at the edge of a spiral arm called the Orion Arm and is about two-thirds of the way from the center of our galaxy to the edge of the starlight.  Our location is a very good one that once again provides relative stability and safety. 14. The Stability of the Galaxy.  The Milky Way galaxy is also rather small compared to some of the giants that occupy the universe.  This too could decrease the odds of dramatic and cataclysmic events that might take place in a dense, massive galaxy. 15. The Stability of our Quantum Universe  Our quantum universe seems apparently stable with firm laws of motion, energy, matter and gravity consistently applied across the universe.  We may also be living in a Goldilocks universe. __________________________________________________________________________________________________ Earth’s Subsystems Earth as a SYSTEM  a set of interdependent components that are interacting and enclosed within a defined boundary. Lithosphere  From the word lithos meaning rock  Composed of the entire earth’s crust and the rigid upper mantle  Extends from the surface of the earth to a depth of about 70-100km Hydrosphere  From the word hydro meaning water  Composed of all the planet's solid, liquid, and gaseous water  Nearly 71% of the earth’s surface is covered by bodies of water. Atmosphere  From the word atmos meaning vapor  Composed of all the planet's air. Biosphere  From the word bio meaning life  Composed of all the planet's living organisms  Biome is a major community of plants and animals with similar life forms and environmental conditions Earth System Science (ESS)  The study of the interaction between and among events and the earth’s spheres  A relatively new science (1988) Events  Changes that take place within an ecosystem  Ex. Typhoon Earthquake Volcanic Eruption Oil Spill Air Pollution Interaction  The two-way cause-and-effect relationship between an event and a sphere 10 Possible Types of Interaction  Event ↔ Lithosphere  Event ↔ Hydrosphere  Event ↔ Biosphere  Event ↔ Atmosphere  Lithosphere ↔ Hydrosphere  Lithosphere ↔ Biosphere  Lithosphere ↔ Atmosphere  Hydrosphere ↔ Biosphere  Hydrosphere ↔ Atmosphere  Biosphere ↔ Atmosphere __________________________________________________________________________________________________ MINERALS Mineral  is a homogenous, naturally occurring, inorganic solid  has a crystal structure and a definite chemical composition  are identified based on their physical properties Atom  Atoms make up minerals and are the smallest component of matter \  Each element is defined by the number of protons and must be electrically neutral  The number of protons equals the number of electrons 5 Characteristics that all minerals share  Naturally occurring  Inorganic  Solid  Crystal structure  Definite chemical composition Naturally Occurring  Naturally occurring means that the substance must occur in nature, it cannot be created/manufactured by people. Inorganic  Inorganic means that a mineral cannot come from something that was once living.  For example, although coal was formed naturally in earth’s crust it came from plants and is therefore, NOT a mineral. Solid  A solid has a definite volume and shape.  Its particles are tightly packed together and cannot move easily. Crystal Structure  Crystal form is the visible expression of a mineral’s internal arrangement of atoms.  A crystal has flat sides called faces that meet at sharp edges and corners  Ex: Gold, halite or salt crystal has a cubic crystal structure while mica has a platy crystal structure. Definite chemical composition  Definite chemical composition means that a mineral always contains certain elements in definite, or exact, proportions Ice  ice is a mineral when it forms naturally, but it is not a mineral when people play a role in producing it. Mineraloid  a material that meets some of the requirements of being a mineral but falls short. Salt  Early people collected salt before they understood how important the mineral is for survival  Mediterranean-salt cakes were used as money while Greeks traded salt for slaves Mineral Resource  A mineral resource is a concentration or natural occurrence of material which are useful and profitable for mankind __________________________________________________________________________________________________ Physical Properties Physical properties  are intrinsic rock properties, which include color, luster, streak, hardness, and cleavage or fracture. Color  Can be misleading  Many minerals will have a similar appearance, but will have different impurities  Color and appearance are not enough to distinguish minerals Luster  This is the quality of light the mineral reflects from its surface  There are two main classifications: metallic and non-metallic  Minerals with metallic luster, most of the time, contain metals  Luster may be described with various adjectives Hardness  This is the mineral’s capability to resist scratching from other materials  There is a standardized hardness value for every material in the Moh’s Scale of Hardness  Concept: If the material can scratch another, the material that is scratched has a lower hardness Hardness VS Brittleness  Hardness – resistance to scratch  Brittleness – resistance to breakage, referred to as tenacity  Diamond is the hardest substance known to humankind, but it's very brittle. Only a diamond can scratch another diamond. Streak  The color of the powdered form of the mineral called “True color” of the mineral  We find a minerals streak by rubbing it on an unglazed black or white ceramic (porcelain) plate  The color of the streak can be different than the mineral Minerals must be softer than the streak plate  The color of the mineral is not necessarily the color of the streak. Streak is a more reliable property to be used in mineral identification Cleavage & Fracture  The way the mineral breaks  Cleavage and fractures are highly dependent on the crystal structure of the mineral.  Minerals with tighter molecular packing tend to fracture. Those with weaker molecular packing tend to break in their cleavage planes Cleavage  minerals break along smooth surfaces and every fragment has the same general shape. Fracture  minerals that break at random flat with rough or jagged edges Special Properties of Minerals  Fluorescence  Chemical Reaction  Optical Properties  Taste  Radioactivity  Magnetism How Minerals are Identified  Minerals are identified based on their physical properties  Each mineral has its set of physical properties unique to it  Scientific identification of minerals include listing their physical properties observed and comparing it to a standardized set of properties from mineral manuals  Skill of mineral identification can be developed through time with practice and field experience __________________________________________________________________________________________________ Mineral Groups 1. Silicates  Silicon and oxygen combine to form a structure called the silicon-oxygen tetrahedron.  This silicon- oxygen tetrahedron provides the framework of every silicate mineral.  Silica tetrahedron form complex silicate structures to form different silicate minerals 2. Carbonates  Minerals that contain the elements carbon, oxygen, and one or more other metallic elements 3. Oxides  Minerals that contain oxygen and one or more other elements, which are usually metals 4. Sulfates and Sulfides  Minerals that contain the element sulfur 5. Halides  Minerals that contain a halogen ion plus one or more other elements 6. Native elements  Minerals that exist in relatively pure form Why are minerals grouped into basis of molecular composition?  They are grouped as such because groups tend to have similar physical properties which narrow down the mineral identification process  Every mineral group has a distinctive characteristic attached to it:  Complex silicates tend to be good construction materials because of their stable form  Carbonates tend to react with acid  Sulfides and sulphates usually indicate presence of metallic deposits