Earth Science lesson 1-4.docx

**Lesson 1: Universe and Solar System** **Formation of the Universe** **Big Bang Theory** The big bang theory is a cosmological model that explains how the universe began. It suggests that the universe started its expansion about [ **13.8 billion years ago**] based on latest calculations....

**Lesson 1: Universe and Solar System** **Formation of the Universe** **Big Bang Theory** The big bang theory is a cosmological model that explains how the universe began. It suggests that the universe started its expansion about [ **13.8 billion years ago**] based on latest calculations. The concept of big bang is **[not a literal explosion]** of something that led to the creation of the universe. **Cosmic Inflation Theory** Proposed by physicists **[Alan Guth and Andrei Linde]** in the 1980s. It states that the early universe was a **[rapidly expanding bubble of pure vacuum]** energy. It did not have any matter or radiation. After the expansion and cooling due to the inflation, the [potential energy was converted into kinetic energy] of the matter and radiation. Then a big bang occurred because of the extremely hot dense condition of matter. **Steady State Theory** It states that the universe is always **[expanding and new matter is constantly formed]** as the universe continues to expand. This theory further claims that the **[universe has no beginning or end]** in time, and even though it is expanding, its appearance remains the same over time. ⚫It was [first proposed by Sir James Jeans in 1920] and it gained popularity after it was [revised by Sir Fred Hoyle, Sir Hermann Bondi, and Thomas Gold] in 1948 as an alternative to the big bang theory. **Formation of Solar System** **Nebular hypothesis** It was developed by [Immanuel Kant (1724-1804) and Pierre-Simon Laplace (1749-1827)] in the 18th century.  It presupposes that around 4.5 billion years ago, a star system was formed from a **rotating cloud of gas and dust-or nebula- of extremely hot gas.** **Planetesimal Theory** Proposed by **(a)Viktor S. Safronov (1917-1999) in 1941** and developed by (b)T.C Chamberlin (1843-1928) and (c)F.R. Moulton (1872-1952) states that in the early period of the solar system, planets were formed from the accretion of small space bodies. **Tidal theory** ⚫ It was developed by **James Jeans (1877-1946) and Sir Harold** **Jeffreys (1891-1989)** in 1917.  A star passed close to the sun where the tidal force or the secondary effect of gravitational pull between the passing star and the sun drew large amounts of matter out of the sun and the passing star. Lesson 2: Earth The Beginnings of Earth The theory of the nebular hypothesis states that Earth, just like the other planets that moved out of the solar nebula, started out as immensely hot gaseous mass. · Uniqueness of Earth There is life on Earth. Earth is where energy flows continuously within its system. WATER IS LIFE ATMOSPHERE **Lesson 3: Earth System** **The Systems of Earth** Earth\'s system refers to Earth\'s interacting physical, chemical, and biological processes. ✓ Atmosphere ✓ Geosphere ✓ Hydrosphere ✓ Biosphere **Gaia hypothesis**- states that [organisms interact with their inorganic surroundings] and establish a self- regulating, complex system that helps maintain the conditions necessary for life on the planet. **Geosphere** It is the solid portion of the Earth includes the interior structure, rocks and minerals, landforms, down to the deep depths of the core, and the processes that shape Earth\'s surface. **STRUCTURE OF THE EARTH** **Crust** It consists of a 5- to 70-km thick layer of oceanic and continental crust overlaying another thick layers of rocks and metals. The [oceanic crust is thicker than oceanic crust.] Most of the crust is composed of elements that include oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium.  **Mohorovicic Discontinuity or Moho** This boundary was discovered by Croatian seismologist Andrija Mohorovicic (1857-1936) in 1909 while [studying the seismic waves in an earthquake in Croatia.] It is now recognized as the transitional boundary that divides the crust from the mantle. **Mantle** It is made of [solid rock, is the largest part of the earth, and makes up 84%] of Earth\'s total volume. At the upper part of the [mantle directly below the crust is the asthenosphere]. The extreme temperature and pressure in the asthenosphere causes the rocks to [become ductile and thus move like liquid]. **Gutenberg discontinuity** The transitional boundary between the mantle and the core. It was named after its German discoverer, Beno Gutenberg (1889-1960). **Core** It is made up of iron (Fe) and nickel (Ni). The [iron in the outer core is in liquid form], which is why the iron core is known to be liquid while [the inner core is solid]. **Lehmann discontinuity** The transitional boundary between the inner and the outer core which was [discovered in 1929 by Danish seismologist **Inge Lehmann (1888-1993)**] when a large earthquake occurred near New Zealand. **The Hydrosphere** It is the total amount of water found on Earth. This includes water in [various forms-whether in ice, vapor, or liquid, found on or below the surface] of Earth and in gas in the atmosphere. **The Hydrological Cycle** Water moves through the hydrosphere in a cycle. The sun\'s energy is the power that drives the water cycle. Light and heat causes water to evaporate from oceans, lakes, rivers, and other sources of water. Distribution of Water on Earth While earth is surrounded with 70% water, only less than 2.5% of it canbe used for human needs. The waters are divided into two groups: surface water and groundwater. **Surface water** Surface water may either be [salt water or freshwater]. Salt waters have [higher salt content and are found in larger bodies of water such as oceans, seas, bays and gulfs.] Freshwater [are those found in lakes, rivers, streams, and falls] which, because of lower content, are the best source of drinking water for all organisms. **Groundwater** It is the water found beneath Earth\'s surface in the zone of saturation (where every pore space between rock and soil particles is saturated with water. **The Atmosphere** The earth is enveloped by thin layer of gas called the atmosphere. **Composition of the Atmosphere** The present atmosphere is composed of [78% nitrogen, 21% oxygen, and 1% other gases such as carbon dioxide, argon, and water vapor.] **Layers of the Atmosphere** The atmosphere is composed of various layers which differ in thickness, temperature, and density. It is these layers that protect Earth from many external threats in space, such as impacts from celestial bodies, and radiation. ✓ Troposphere ✓ Thermosphere ✓ Stratosphere ✓ Exosphere ✓ Mesosphere **Troposphere** The densest among the layers of the atmosphere because of the weight of all the other layers compressing it. Most types of clouds are in troposphere as high as 12 miles or 65 000 feet near the equator and 4 miles or 20 000 feet over the poles in winter. **Stratosphere** The air in this layer has strong, steady horizontal winds which are advantageous to long-distance flights. At its upper region is the ozone layer at about 6.2 miles or about 33 000 feet above Earth\'s surface which contains a high concentration of ozone. **Mesosphere** The temperature here reaches a minimum of - 90°C and is considered to be the coldest layer. The mesosphere is important in protecting Earth from planetary debris. **Thermosphere** The hottest because it absorbs highly energetic heat from the sun. The lower part of the thermosphere is the ionosphere where most collision of oxygen and nitrogen particles are electrically charge by the solar wind. **Exosphere** The temperature of the exosphere can reach up to 2,700 °F (1,500 °C) during intense solar storms. The gravity in the exosphere is very weak. **The Biosphere** It is a closed system that makes up all the living components of Earth. The biosphere interacts and exchanges matter and energy with the other systems.  Lesson 4 : Rock and Minerals **MINERALS** It is a [naturally occurring, inorganic, homogeneous solid, with a definite chemical composition, and an ordered crystalline structure].  **PHYSICAL PROPERTIES OF MINERALS** **COLOR** -It refers to certain wavelengths of light that are reflected by a mineral and is perceived by the observer. **STREAK** - The color of the powdered form of a mineral. **LUSTER** - The appearance of a mineral\'s surface and is dependent on how it reflects light. **CRYSTAL HABIT** - The characteristic shape in which a mineral arows and is a proiection of the mineral\'s crystal structure. **CLEAVAGE** - The tendency of some minerals to break along flat surfaces. **FRACTURE** - The pattern in which the mineral breaks aside from its planes of cleavage. **HARDNESS** - The resistance of the minerals to scratching. **SPECIFIC GRAVITY** - The ratio of a minerals\' weight to the weight of an equal volume of water. **CHEMICAL PROPERTIES OF MINERALS** **SOLUBILITY** - The ability of a substance to dissolve in a solvent at a specified temperature. **MELTING POINT** - The temperature at which solid turns into liquid. **TYPES OF ROCKS** **IGNEOUS ROCKS** - laneous rocks are [formed from solidification of magma or lava] which flows out from depth.  TYPES OF IGNEOUS ROCKS An **EXTRUSIVE IGNEOUS** **ROCK** forms [when magma or volcanic fragments erupt and solidify on Earth\'s surface] which results in very fine-arained rock with very small crystals that could not be seen through naked eye. **(LAVA)** An I**NTRUSIVE IGNEOUS ROCK** forms when [magma crystallizes within the crust] and is composed of medium to coarse arains. It is also known as a **plutonic rock**. (MAGMA)  **SEDIMENTARY ROCKS** Sedimentary rocks were formed from [organic, mechanical or chemical sediments]. A process called **lithification** is where harden sediments become sedimentary rocks. **TYPES OF SEDIMENTARY ROCK** Clastic Sedimentary Rocks are [made up of sediments from preexisting rocks.] Ex. Breccia, Conglomerate, Sandstone **Chemical Sedimentary Rocks** form from [chemical precipitation.] Ex. Gyspum, Rock salt, Chert, Travetine **Biological Sedimentary Rocks** are [lithified accumulation of dead organisms.] Ex. Chalk, Limestone with fossil, coal **METAMORPHIC ROCKS** **Metamorphic rocks** are rocks that have been altered, changed, or transformed in the solid state due to changes in [pressure, temperature conditions, and chemical actions of hot fluids.]  **FORMATION OF METAMORPHIC ROCKS** Metamorphism refers to the alteration of rocks due to different factors like temperature and pressure. Regional Metamorphism Contact Metamorphism **TYPES OF METAMORPHISM** **Contact Metamorphism** occurs only at a local area adjacent to large intrusions and along fractures that are in contact with hot fluids. **Regional Metamorphism** occurs when there are major igneous intrusions. presence of extreme pressure and heat due to deep burial.  **Foliated Metamorphic Rocks** are formed when parallel planes of platy or elongated minerals creating what is called as **foliations**. **Nonfoliated Metamorphic Rocks** do not have lauered appearance. Examples are marble. quartzite. and anthracite.