Lesson 2: Earth and Life Science PDF

1st Quarter LESSON 2 Week 2 Earth and Life Science  OBJECTIVES At the end of the lesson the student must be able to: Define minerals and rocks Describe different properties of minerals Identify common rock-forming minerals Classify rocks into igneous,...

1st Quarter LESSON 2 Week 2 Earth and Life Science  OBJECTIVES At the end of the lesson the student must be able to: Define minerals and rocks Describe different properties of minerals Identify common rock-forming minerals Classify rocks into igneous, sedimentary and metamorphic.  INTRODUCTION Earth, being a terrestrial planet, is composed of rocks and minerals as part of the geosphere. The geosphere is solid and it includes the lithosphere, with the outermost layer of our planet composed of the crust and the upper mantle. The lithosphere extends to a depth of about 100 kilometers down the surface containing different rocks and minerals from both the continents and the oceans.  MINERALS Minerals are naturally occurring, inorganic solid with orderly crystalline structure and a definite chemical composition. These are the basic building blocks of rocks. Water is not a mineral since it is not solid and crystalline. Tube ice is not because it is not naturally occurring. Snow flake meets all requirements in defining a mineral  PROPERTIES OF MINERALS 1. LUSTER Luster is the quality and intensity of reflected light exhibited by the mineral a. Metallic – generally opaque and exhibit a resplendent shine similar to a polished metal b. Non-metallic – vitreous (glassy), adamantine (brilliant/diamond-like), resinous, silky, pearly, dull (earthy), greasy, etc.  PROPERTIES OF MINERALS 2. HARDNESS OF A MINERAL It is a measure of resistance of mineral to scratching or abrasion; test using Moh’s Scale of hardness by scratching them with common objects of known hardness (e.g. copper coin -3.0-3.5).  PROPERTIES OF MINERALS 3. COLOR Physical color of mineral with impurities, unreliable for identification of mineral. One mineral can come in many colors. For example, Hematite- comes in black, red and brown  PROPERTIES OF MINERALS 4. STREAK It is the inherent color of the mineral, usually in powdered form (done when scratching) Example: pyrite (FeS2) has a golden color, known as Fools gold, but has a black or dark gray streak. PROPERTIES OF MINERALS 5. CRYSTAL FORM/HABIT The external shape of a crystal or The form reflects the groups of crystals is displayed / supposedly internal observed as these crystals grow in structure (of atoms and open spaces. ions) of the crystal (mineral). It is the natural shape of the mineral before the development of any cleavage or fracture.  PROPERTIES OF MINERALS CRYSTAL FORM/HABIT Examples include prismatic, tabular, bladed, platy, reniform and equant. A mineral that do not have a crystal structure is described as amorphous.  PROPERTIES OF MINERALS 6. CLEAVAGE It is the property of some minerals to break along parallel repetitive planes of weakness to form smooth, flat surfaces. These planes of weakness are inherent in the bonding of atoms that makes up the mineral. These planes of weakness are parallel to the atomic planes and appear to be repeating within the mineral. PROPERTIES OF MINERALS CLEAVAGE When minerals break evenly in more than one direction, cleavage is described by the number of cleavage directions and the angle(s) between planes (e.g. cleavage in 2 directions at 90 degrees to each other).  PROPERTIES OF MINERALS 7. FRACTURE Some minerals may not have cleavages but exhibit broken surfaces that are irregular and non- planar. Quartz for example has an inherent weakness in the crystal structure that is not planar. Examples of fracture are conchoidal, fibrous, hackly, and uneven among others.  PROPERTIES OF MINERALS 8. SPECIFIC GRAVITY It is the ratio of the weight of a mineral to the weight of an equal volume of water. It is a measure to express the density (mass per unit volume) of a mineral over the density of water (1g/mL). The specific gravity of a mineral has no unit. ROCKS Rocks are inorganic, solid combinations of minerals such as fossils and glass. Just as minerals are the building blocks of rocks, rocks are the natural building blocks of Earth’s Lithosphere. Example: Granite is rock composed of minerals: Quartz, Feldspar, Mica IGNEOUS ROCKS These rocks were formed from the solidification of molten rock material. The process of solidification involves the formation of crystalline solids called minerals. Molten rock material can solidify below the surface of the earth (plutonic igneous rocks) or solidify at the surface of the Earth (volcanic igneous rocks)  IGNEOUS ROCKS TYPES OF IGNEOUS ROCKS a. Intrusive/Plutonic- igneous rocks crystallize below Earth's surface b. Extrusive/ Volcanic - igneous rocks crystallize at the Earth's surface  SEDIMENTARY ROCKS Rocks that were formed through the accumulation, compaction, and cementation of sediments. Sedimentary rocks form at surface or near surface conditions. SANDSTONE Example: sandstone, a sedimentary rock that formed from sand grains and a limestone, a sedimentary rock made of calcium carbonate that formed under water indirectly from the remains of tiny LIMESTONE marine organisms.  METAMORPHIC ROCKS These are rocks that were formed through the transformation of pre- existing rocks (igneous, sedimentary, or metamorphic rocks) through the process of metamorphism. Metamorphism can involve changes in LIMESTONE the physical and chemical properties of rocks in response to heat, pressure, and/or chemically active fluids. REFERENCES Olivar, Ramos et al.,(2016).Exploring Life Through Science Series: Earth and Life Science. Philippines. Phoenix Publishing House, Inc. Earth and Life Science Teacher’s Guide Earth and Life Science Teacher’s Manual Earth and Life Science Learner’s Material