Transcript Slide 1
Let’s Get Well Grounded Roberta Johnson, Lisa Alter, Richard Jones, Michelle Harris, Missy Holzer, Dave Mastie, Parker Pennington IV National Earth Science Teachers Association, Boulder, CO Fall, 2011 Workshop Overview • Introduction to Geology • Silicon Tetrahedron • Let’s Take a Rock Apart • Milky Way Tectonics • Cookie Mining • Terrabagga Earth • The third planet from the Sun, it is the largest of the inner planets. • Earth is the only planet known to support life and to have liquid water at the surface. • Earth has a substantial atmosphere and magnetic field, both of which are critical for sustaining life on Earth. Earth’s Interior • Earth's interior consists of rock and metal. It is made up of four main layers: - the inner core: a solid nickel iron metal core - the outer core: a liquid molten nickel iron core - the mantle: dense and mostly solid silicate rock - the crust: thin silicate rock material • • • Temperatures in the inner core rise to 9000 F. Intense heat from the inner core causes material in the molten outer core and mantle to move. Movement of material deep within the Earth causes large plates made of the crust and upper mantle, called the lithospheric plates, to move slowly over the Earth’s surface. Currents in the Earth’s outer core generate the magnetic field. Plate Tectonics • • • • Plate tectonics is the main force that shapes our planet’s surface over long amounts of time. The lithosphere is made of relatively low density plates which fit together like a jigsaw puzzle. Movements deep within the Earth, which carry heat from the hot interior, cause the plates to move very slowly on the surface - about 2 inches per year. Subduction zones and mountain ranges form when plates crash into each other, spreading ridges when plates pull away from each other, and large faults when plates slide past each other. Seafloor Spreading and Plate Tectonics Minerals • Minerals are the building blocks of rocks. • Different types of minerals have different crystal shapes. Most minerals can grow into crystal shapes if they have enough space as they grow. – Silicate minerals are the most common mineral group on Earth, most commonly forming when molten rock cools. – Non-silicate minerals form in a number of ways, including when magma cools, when water evaporates away, or when other minerals decompose. • Minerals can be identified by their physical properties. Sedimentary Silicates • • • • Silicates can also form through deposition of dissolved silicates in sedimentary rock. Cherts (flint, agate, and jasper) are hard, glassy sedimentary rock composed of silica precipitated from water. Chert nodules (geodes), are commonly found in limestones, forming in pockets once occupied by other material that has since been removed. Cherts also occur as continuous layers in sedimentary rocks, and usually composes at least half of the layered rock in banded iron formations, crystallizing in shallow seas (an important source of iron). Granite • The most common type of intrusive igneous rock that we have at the Earth’s surface. • Composed of crystals of common silicate minerals such as quartz, plagioclase feldspar and orthoclase feldspar. • May also contain small amounts of mica. • Because granite is very hard, it often used to make buildings, kitchen countertops, tombstones, and sculptures. Silicon Tetrahedron, SiO44• • • • • • More than 90% of the minerals in the Earth's crust are members of the silicate family. In all silicates, the silica tetrahedron is the basic building block. The silica tetrahedron consists of 4 Oxygen atoms (raisins) bonded to 1 Silicon atom (bubble blown in middle of pyramid). Bonding with other ions allows the charge to be reduced, forming diverse silicate minerals What other common molecules have tetrahedral Model building allowing students to structure? visualize a complex structure • Methane (CH4) and Ammonium ion (NH+4) Use as a starter for discussion about • The central angle between any two vertices silicate minerals or crystal structure. of a perfect tetrahedron is approximately 109.47°) Let’s Take a Rock Apart Earth’s Natural Resources There are two broad categories of resources • • Renewable – which can be replenished from – plants – water, sun, and wind Nonrenewable – which cannot be replenished over geologically “short” intervals – Metals, stone – Fossil fuels Why we mine… • Many products we use today require minerals and metals that are only available within the Earth. • In many communities, the energy that fuels our lives comes from coal, which must be mined. • Mining in a way that minimizes damage to the environment poses real challenges. Types of Coal Mining http://www.uky.edu/KGS/coal/coal_mining.htm Cookie Mining… Milky Way Tectonics Terrabagga activity Windows to the Universe Educator Newsletter Sign up now! Questions? www.windows2universe.org Friday, November 11 All events in Ernest N. Morial Convention Center, R09! 8:00 – 9:00 am, Let’s Get Well Grounded! 9:30 – 10:30 am, Climate Change Classroom Toolkit 11:00 am - noon, Activities Across the Earth System 2:00 – 3:00, NESTA Share-a-Thon 3:30 – 4:30, NESTA Rock and Mineral Raffle! Session evaluations are available at http://www.nsta.org/conferences/evaluations Please join us at the NESTA Share-a-Thon. 2-3 pm Rock and Mineral Raffle, 3:30 – 4:30 pm This room, today! Great classroom Activities! Rocks & Mineral Fossils & Maps Kits, and many other goodies! No one goes away empty handed!