Science Lessons 1-5 PDF

# 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 the latest calculations. - The concept of big bang is not a literal explosion of something that led to th...

# 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 the latest calculations. - The concept of big bang is not a literal explosion of something that led to the creation of the universe. ## Big Bang Theory and the Bread-Raisin Model - The bread represents the universe, while raisins are the galaxies. - The galaxies, represented by the dots, are not expanding. - Distances in relation to other galaxies just increase because of the expanding universe. ## Singularity - The universe started as a “singularity,” an area predicted to be in the core of a black hole with very high temperature and density. - The intense heat resulted in the formation of matter and antimatter particles that were destroyed every time they collided with each other. ## Nucleosynthesis - Is the formation of elements, such as H and He. - Presence of these elements led to the formation of stars and galaxies. - The presence of stars led to the formation of other cosmic bodies, such as planets, comets, and asteroids. ## Evidence That Support the Big Bang Theory - The expansion of the universe is supported by the observation that galaxies are receding from us. - The high amount of light elements, such as H, He, and Li. These elements were formed through the fusion of protons and neutrons immediately after the big bang. - The detection of the cosmic microwave background (CMB) radiation, which is the residue or heat leftover from the big bang. ## Proponents of the Big Bang Theory ### Georges Henri Joseph Edouard Lemaître - Was the first proponent of the theory. He suggested the idea of the expanding universe. ### Edwin Powell Hubble - Established the Hubble's law, which provided an evidence that the universe was not static but expanding. ### Arno Penzias and Robert Wilson - Discovered that microwaves with wavelengths of about 7 cm were present in space. - These waves were referred to as the cosmic microwave background (CMB) radiation. ## Drawbacks of the Big Bang Theory - It fails to explain how the universe was created. - It just explains how the universe evolves and not where it originated. - It also fails to explain how the galaxies formed. # Steady-State Theory - The steady-state theory is another view that proposes that the universe has always been expanding. - As the universe expands, new stars and galaxies are formed at the same rate that old ones become unobservable due to distance and recession velocity. - Despite the continuous expansion, the average density of the universe remains the same; hence, the name steady state. ## The universe, according to the Steady-State Theory: - Has no beginning and has no end. - Has always been here and will always be present. - Always looks the same in any time and space. - Creates new matter as it continuously expands. # Nebular Theory - According to the nebular theory, the solar system originated from a nebula. - It is the widely accepted view about the formation of the solar system some 4.5 billion years ago. - A nebula is defined by NASA as giant cloud of gas and dust in space. - This interstellar cloud of dust contains hydrogen, helium and other ionized gases. ## Major Steps in the Formation of the Solar System ### (1) Cloud collapse - Hypothetically, a shockwave from a supernova or the effect of a passing star may cause a cloud collapse. - The collapse at the center of the cloud due to gravity occurs when gas pressure becomes insufficient to support the mass of the cloud. # Encounter Theory - The encounter theory proposes that the planets were formed from the material ejected from the sun during an encounter with another celestial object, such as another star. - Two forms: planetesimal and tidal theories ## Planetesimal Theory - It proposes that a passing star termed as intruding star nearly collided with the protosun. - The massive gravitational pull of the intruding star causes the protosun to eject filaments of material which then condensed into planetesimals. - This theory describes how Earth started from a solid mass smaller than its present size. ### Proponents of the Planetesimal Theory - Thomas Chrowder Chamberlin proposed that accretion of minute solid particles created planets and their moons rather than by # Accretion - Accretion is one of the leading theories about the formation of planet Earth. - It is a process that occurs when gravity attracts tiny bits of matter towards an object. - Accretion forms planetesimals, which form protoplanets. - A protoplanet is a planetary embryo that consists of a collection of matter, from which a planet is formed. ## Steps of Accretion - Clump of dust grains - Physical collision - Planetesimals - Protoplanet ## Homogeneous Accretion - It is when Earth accreted from materials of the same composition after condensation. - Homogeneous accretion is a process where a celestial body, like a planet, forms from a uniform mix of materials. ## Heterogeneous Accretion # The Origin of Water on Earth - The prevailing hypothesis on the origin of water on Earth suggests that water came from comets that collided with Earth. - Other studies suggest that water was already present within Earth since formation as volatiles trapped in magma. ## Key Points - Hydrosphere is the water environment on Earth. - Saltwater is found in bodies of water like oceans and seas. As the name implies, saltwater contains salt. - Freshwater may still have salts but in very low concentrations. Freshwater can be present in the form of rain and snow, and it can even be found in permanently frozen soil known as permafrost. It can also be stored in rivers, streams, ponds, lakes, marshes, glaciers, and polar caps. - Water has the right density, transition temperatures, and heat capacity that enable the existence and perpetuation of life. - There are two primary theories about the origin of water on Earth. # The Sun - The Sun is the Earth's main source of energy, and powers many of the processes in the planet. - Plants are dependent on the sun for photosynthesis. ## Solar Energy is Renewable - As long as the sun shines, solar energy is available for everyone to utilize. - This is advantageous since the sun is an environmentally friendly source of energy. # Earth's Energy Budget - Earth's energy budget is the balance of energy absorbed and energy reflected. - 30% of the energy from the sun is reflected and scattered by clouds, atmosphere, and Earth's light-colored surfaces. ## Factors Affecting Earth's Energy Budget - The amount of light-colored surfaces - Amount of radiation received - Earth's axial tilt - Presence of greenhouse gases. ## Key Points - Albedo is the ability of a material to reflect light. - Earth's energy budget ensures that the absorbed solar radiation is balanced with the radiated ones. Keeping Earth's energy budget ensures that the average temperature on Earth remains stable and that life continues to exist. # Ozone - Ozone is a special kind of oxygen found in the Earth's atmosphere. While regular oxygen molecules have two oxygen atoms (O2), ozone molecules have three oxygen atoms (O3). Ozone is important because it forms a layer high up in the atmosphere, called the ozone layer, which protects us by absorbing most of the Sun's harmful ultraviolet (UV) radiation. - This "sunscreen" helps prevent skin cancer and other damage caused by too much UV exposure. ## Layers of the Atmosphere - Troposphere is where humans and most of the biosphere reside and is the lowest layer. - Stratosphere contains the ozone layer. - Mesosphere is where meteorites burn up. - Thermosphere is a layer with extremely high temperatures. - Exosphere is the outermost layer of the atmosphere, and the layer in contact with outer space. - To easily remember the layers of the atmosphere, use the mnemonic “The Smart Man Takes the Elevator”. ## The Stratospheric and Tropospheric Ozone - Stratospheric ozone is good while tropospheric ozone is bad. - These harmful ozones when inhaled, can irritate the lungs and breakdown lung tissues. ## Atmosphere's Role in the Hydrologic Cycle - The atmosphere is a crucial part of the water cycle. It serves as the reservoir of large amounts of water. - Therefore, the atmosphere is an efficient medium to move water around the globe. # Earth System Science - It is the study of Earth as an integrated system. It seeks to understand the past, current, and future state of our planet. - The interdisciplinary nature of ESS led to the development of new ideas for research, as well as promoting scientific studies to people of different backgrounds. ## Contributor Scientists - Alexander Humboldt – Organism dispersal and distribution - Vladimir Vernadsky – The noosphere - James Hutton – Father of modern geology - James Lovelock & Lynn Margulis – The Gaia Hypothesis ## The Gaia Hypothesis - The Gaia Hypothesis states that the Earth is a self-regulating system. - Organisms interact with their surroundings and other organisms. These interactions make Earth self-sustaining. ## NASA ESS Committee - NASA scientists aim to understand Earth's systems by using satellites for long-term observations. - Scientists and data analysts process the data for human use. Examples of uses are for weather, atmospheric analysis, and many more. ## Satellite Imagery - Satellites can take photos of the Earth from space for various purposes. ## Key Points - An Earth System Science Committee was formed by NASA in 1983. - Several scientists have contributed to the study of ESS. - Knowledge on Earth System Science is essential to understand Earth's components that are essential in our daily lives and useful in drafting policies for conservation of our planet. ## Four Subsystems of Earth # Hydrosphere - It is composed of all water on Earth in any form: water vapor, liquid water, and ice. - It is comprised of 97.5% saltwater and 2.5% freshwater. # Biosphere - It includes all the organisms on Earth and their interrelations. - Biosphere consists of all living things including the microorganisms. ## Key Points - Atmosphere includes the gases, and has five distinct layers. - Geosphere includes the ground, and has three distinct layers. - Hydrosphere includes all of the watery environments on the planet. - Biosphere includes all the planet's living organisms that interact with each other. # Earth's Climates System - Weather - short-term changes - Climate - long-term patterns ## Factors Affecting the Climate - Greenhouse Gases - These are gases that trap heat. - Examples are water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O,) and ozone (03). - Hydrosphere # Biogeochemical Cycles - How do plants take carbon dioxide and water from its environment then return it in the form of oxygen and carbon- based materials? - Interactions between the subsystems and living organisms allow recycling of these materials to make Earth a self-regulating system. -The Earth has multiple cycles of energy and matter that affect many of its subsystems. Complete topic - Some of these cycles even affect multiple subsystems at the same time. ## The Hydrologic Cycle - The movement of water from the ocean to the atmosphere to land and back to the ocean is called the water or hydrologic cycle. ## Steps of the Hydrologic Cycle - Evapotranspiration: Liquid water to gas. Water from oceans, lakes, rivers, and the soil evaporates into the atmosphere as water vapor. Plants also contribute by releasing water vapor through transpiration. - Condensation: The formation of clouds. The water vapor rises and cools in the atmosphere, condensing into tiny droplets to form clouds. - Precipitation: The release of water from the clouds. When the droplets in the clouds become too heavy, they fall back to Earth as precipitation, such as rain, snow, or sleet, replenishing water sources and continuing the cycle. ## The Nitrogen Cycle - It refers to the transference and conversion of nitrogen across many forms. - Both organisms and natural processes (like lightning) play a role in the nitrogen cycle. ## Steps of the Nitrogen Cycle - Nitrogen Fixation: Atmospheric nitrogen (N2) is converted into ammonia (NH3) or related compounds by bacteria in the soil or through industrial processes, making nitrogen available to plants. - Nitrification: Soil bacteria convert ammonia into nitrites (NO2¯) and then into nitrates (NO3¯), which plants can absorb and use to grow. - Assimilation: Plants take up nitrates from the soil and use them to build proteins and other essential molecules. Animals then # Rock Forming 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 refers to certain wavelengths of light that are reflected by a mineral and is perceived by the observer. - Streak is the color of the powdered form of a mineral. - Luster is the appearance of a mineral's surface and is dependent on how it reflects light. - Crystal habit is the characteristic shape in which a mineral grows and is a projection of the mineral's crystal structure. - Cleavage is the tendency of some minerals to break along flat surfaces. - Fracture is the pattern in which the mineral breaks aside from its planes of cleavage. - Hardness is the resistance of the minerals to scratching. - Specific gravity is the ratio of a minerals' weight to the weight of an equal volume of water. ## Chemical Properties of Minerals - Solubility refers the ability of substance to dissolve ins a solvent at specified temperature. - Melting point refers to the temperature at which solid turns into liquid. ## Analysis of the Composition and Crystal Structure of Minerals - Wet chemical analysis - involves dissolving a mineral in an acid and analyzing the solution. - Spectroscopic techniques - involve quantitative analysis of mineral components depending on the light absorbance of the compounds. ## Rock Forming Minerals - Quartz has a chemical composition of SiO2 . It is a glass-like hard substance with white streaks. - Feldspar has a chemical composition of XAlSi3O8, where X is potassium (K), calcium (Ca), or sodium (Na). - Mica is soft, with hardness ranging from 2 to 2.5. It is easily identified by its perfect cleavage, reducing it to thin smooth flakes. # Igneous Rocks - Igneous rocks are formed from solidification of magma or lava which flows out from depth. - Minerals such as quartz, feldspar, pyroxene, olivine, amphibole, and mica are the components of almost all types of igneous rocks. ## Formation of Igneous Rock - Igneous rocks are characterized by intergrowth of crystals and/or volcanic glass. - Crystal size is directly proportional to the cooling rate of magma. - Big crystals are formed deep underground, while smaller crystals are formed near the surface. - Bowen’s reaction series is a general model created to show the progression of silicate crystallization at specific temperature. ## 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-grained rock with very small crystals that could not be seen through naked eye. - An intrusive igneous rock forms when magma crystallizes within the crust and is composed of medium to coarse grains. It is also known as a plutonic rock. ## Naming of Igneous Rocks - Igneous rocks can be named using the binary system which is mainly based on its texture and composition of the rock. ## Key Points - Igneous rock is formed from solidification of magigned fero whisks hawatomposition. - Classifying igneous rock bas - Composition (silica content) re condition. - Texture - Felsic - Intermediate - Mafic - extrusive (volcanic) rhyolite - basalt - gabbro - andesite # Sedimentary Rocks - Sedimentary rocks were formed from harden sediments become sedimentary rocks. - A process called lithification is where harden sediments become sedimentary rocks. ## Formation of Sedimentary Rock - Diagenesis is a collective process where sediments are lithified (becomes rock). It has four main parts: - Compaction - Cementation - Recrystallization # 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. There are many ways by which this occurs. - Recrystallization occurs when small crystals of one mineral will slowly convert to fewer, larger crystals of the same mineral without melting the rock. - Neomorphism is the process whereby minerals not only recrystallize, but also form different minerals from the same chemical elements. - Metasomatism is the addition or loss of elements new minerals form with only some of the original elements, and new elements were added through hydrothermal migration. ## Types of Metamorphic Rocks - 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 hear due to deep burial. - Foliated metamorphic rocks are formed when parallel planes of platy or elongated minerals creating what is called as foliations. (Ex: Slate, Schist) - Nonfoliated metamorphic rocks do not have layered appearance. Examples are marble, quartzite, and anthracite. (Ex: Quartzite, marble) ## Rock Cycle - The rock cycle shows that all rocks are related to each other. - Igneous rocks can change into sedimentary or metamorphic rocks. - Sedimentary rocks may also transform into igneous or metamorphic rocks. - Metamorphic rocks can change into all the three rock types. ## Factors Affecting Weathering of Rocks - Goldich stability series illustrates the relative stability or weathering rate of numerous minerals. This series is roughly the inverse order of original crystallization for minerals found in the Bowen’s reaction series. ## Key Points # Weather - Weathering is the process of breaking down rocks present at Earth’s surface. - Weathering can happen in the presence of the action of rainwater, variable extreme temperature, and different biological activities. ## Mechanical Weathering - Mechanical weathering is a process wherein rocks are broken down into smaller pieces without changing their chemical composition due to several factors like fluctuating temperatures and pressure, and biological activity. ## Types of Mechanical Weathering - Frost wedging - Is a process that involves repeated cycles of freezing and thawing of ice. - Frost wedging happens when there is sufficient moisture, pre-existing cracks, and when temperatures frequently rise and fall. - Salt crystal growth - Is a process that happens when seawater penetrates crevices in rocks which are found mostly in rocky shorelines and arid regions. - Salt crystals expand when subjected to an increase in temperature that causes the widening of crack. - Biological activity - is the action of organisms, including plants and animals, that reduces the size of rocks and minerals which make rocks more susceptible to chemical weathering. - Unloading - happens when, through erosion or uplift, thick layers of sediments overlying deeply buried in rocks are removed. ## Chemical Weathering - Chemical weathering is a process wherein rock materials are changed into other substances that have different physical and chemical compositions. ## Types of Chemical weathering - Dissolution is a process wherein a solid (i.e., halite) dissolves in a liquid (i.e., water). - Hydrolysis is a process where water reacts with a mineral to form a new mineral. - Oxidation occurs when there is chemical combination of oxygen with a mineral to form an entirely different mineral in which at least one of the elements has a higher ionic charge. # Erosion - Erosion is the transportation of weathered rocks. - Agents like running water or rivers, wind, gravity, groundwater, wave currents, and glaciers contribute to erosion. - Erosion has different types: water erosion, wind erosion, and glacial erosion. ## Types of Erosion - Water erosion - is a type of erosion where water carries the sediments to different bodies of water such as rivers. - The high amount of rainfall contributes to susceptibility of the soil to water erosion. - Wind erosion - happens when light materials, such as small rocks and pebbles, are carried by the wind to different places. - Glacial erosion - happens when a glacier, or a river of highly- compact ice, move downhill due to its weight. - It plucks chunks of rocks and causes scraping between the ice and the rock. ## Causes of Erosion - Soil erodibility is the vulnerability of soil to erosion caused by rainfall intensity, soil properties, crop cover, and slope. - The texture of the soil is the most significant contributing factor to erodibility although structure, organic matter, and permeability may also affect it. - Overgrazing by livestock or by indigenous animals may remove vegetation leaving the soil more vulnerable to erosion. - Cutting of trees and removal of vegetation to provide lumber can also result in large amounts of erosion. - Use of pesticides, herbicides, and fuel oils also pollutes the soil. Salt can also contaminate soil due to the high salinity of irrigation water as it passes over croplands. - Cutting of trees and removal of vegetation to provide lumber can also result in large amounts of erosion. - Use of pesticides, herbicides, and fuel oils also pollutes the soil. Salt can also contaminate soil due to the high salinity of irrigation water as it passes over croplands. ## Preventing Soil Erosion - Shaping steep terrains to produce flat areas - Reducing farmland conversion - Planting vegetation - Application of organic fertilizer # Mass Wasting - Mass wasting is a downslope movement of rock, regolith/unconsolidated material, and soil under the influence of gravity. - It is different from erosion because mass wasting does not need any transporting medium such as wind, water, or glacial ice. ## Factors that Cause Weakening of Slopes - Creep is the slow, downhill movement of rock or soil under the influence of gravity. - A debris flow is composed of a mixture of clay, silt, sand, and rock fragments in which more than half of the components are more abundant than sand. - Mudflow has a consistency of wet concrete due to its high water content. ## Types of Mass Wasting - An earthflow contains less water and therefore less fluid than a mudflow. - Solifluction happens when water-saturated soil moves downslope. - A slump occurs when blocks of material move downhill over a gently curved fracture in rock or regolith. - During a rockslide, bedrock slides downslope over a fracture plane. - The fastest type of mass wasting is fall. It is characterized by rapid, free- falling rocks. ## Measures to Prevent Disasters - Hazard maps are used to identify areas susceptible to landslides. - Engineering measures are also applied before any hillslope development. - Soft mitigating measures such as information and educational campaigns and monitoring and early warning systems are also conducted by the local government. # Sediments and Sedimentation - Sediments are loose, unconsolidated, solid particles from weathering and erosion of pre-existing rocks, precipitation of minerals dissolved in water, and remains of plants and animals. - The process in which solid materials are deposited horizontally after it is transported by different agents of sediment transport such as water and wind is called sedimentation. ## Properties of Sediments - Sphericity refers to the degree by which a material approaches the shape of a sphere. - Roundness is the degree of abrasion as shown by the sharpness of the sediment edges and corners. - Sorting describes the degree of uniformity of grain sizes of sediments. Sediments are sorted based on their density caused by the energy of the transporting medium. ## Effects of Sedimentation - Natural sedimentation helps add nutrients to the soil and most of the time develops the coastal habitats such as coral reefs, lagoons, and wetlands. - Corals are mostly affected when there is excessive sedimentation. Since corals do not move, sediments simply lie on top of them and later on killing them. - Siltation is a type of pollution that occurs when silt or clay dominates a body of water. - It refers to the increased amount of suspended sediments and accumulation of fine particles at the bottom of a stream.