Earth Science

1. Earth Science NHSPE Preparation and Tutoring

2. 3 Main Topics • Atmospheric Processes and the Water Cycle • Solar System and Universe • Earth’s Composition and Structure

3. 1. Atmospheric Processes and the Water Cycle • The Sun is the major source of Earth’s energy, and provides the energy driving Earth’s weather and climate. • The composition of Earth’s atmosphere has changed in the past and is changing today. • The greenhouse effect is an essential process to maintaining a habitable temperature range on Earth. • Convection and radiation play important roles in moving heat energy in the Earth system. • Earth’s rotation affects winds and ocean currents.

4. Interactions-Sun and Earth • More than 99% of the Earth’s energy comes from the Sun through visible light. • The Earth also sends energy back into outer space, mostly as infrared radiation. • On average, this transfer of this incoming and outgoing energy is nearly equal. • Of the Sun’s incoming energy: • --about 30% is reflected back to space. • --another 19% of the incoming solar energy is absorbed by the Earth’s atmosphere and clouds. • --the remaining 51% is absorbed by the Earth’s surface.

5. Energy – From Earth to Where? • To maintain equilibrium, the Earth returns the energy it receives from the Sun back to space as infrared light. • Only 6% of the energy goes directly from the Earth’s surface to space. • About 15% of the Earth’s surface energy is absorbed by water vapor, carbon dioxide and other gases in the atmosphere. (greenhouse effect) • The remainder of Earth’s surface energy is transferred to the atmosphere in a more complex exchange involving sensible and latent heat. • Sensible heat is the energy associated with the temperature of a body. A warm surface will be at a higher temperature. Sensible heat flows from the surface to the atmosphere via convection (air circulations) or conduction (molecular motion). • Latent heat is the energy associated with phase changes. In the atmosphere, water vapor condenses forming clouds and precipitation. This releases latent heat to the atmosphere. Latent heat also flows from the atmosphere to the surface during evaporation. Evaporation cools the atmosphere. • So, infrared radiative transfer combined with flux of sensible and latent heat provides the energy to the atmosphere. This energy, which ultimately originated from the Sun, drives all of Earth’s weather and climate.

6. What Does The Sun Energy Do On Earth? • Powers the water cycle. (and many of the other biochemical cycles). • Warms the atmosphere and surface • Drives weather and climate through the uneven heating of the Earth’s surface. • Provides needed energy for photosynthesis in plants

7. Diagram It!

8. The Water Cycle • Water: essential for life on earth. It is recycled through the water or hydrologic cycle. • Amount of water on earth remains nearly constant and is continually recycled through time. • Water molecules may remain in one form for a very long period of time and in other forms for very short times. • Remember, this is all driven by energy from the sun!

9. Water Cycle Processes • Evaporation: changing of water from a liquid to a gas • Condensation: changing of water from a gas to a liquid • Sublimation: changing of water from a solid to a gas • Precipitation: water molecules condense to form drops heavy enough to fall to the earth's surface

10. Water Cycle Processes • Transpiration: moisture is carried through plants from roots to leaves, where it changes to vapor and is released to the atmosphere • Surface runoff, the flowing of water over the land from higher to lower ground • Infiltration: the process of water filling the porous spaces of soil • Percolation: groundwater moving in the saturated zone below the earth's surface

11. Diagram It!

12. Atmosphere –Its Role • Atmosphere Role: protects the Earth’s surface from the sun’s radiation and helps regulate the temperature of the Earth’s surface. • What is the atmosphere? • A mixture of gases the surrounds a planet. • All weather on Earth occurs in the atmosphere and it is essential to life.

13. Atmosphere Composition • Composition of the atmosphere: • Nitrogen 78% • Oxygen 21% • Carbon dioxide 0.03% • Other gases 0.17% • Water vapor (variable) 1-3%

14. Layers of the Atmosphere(The Most Important Ones) • Troposphere: closest to the Earth’s surface and where weather occurs. You can find the majority of the water vapor and carbon dioxide here (hey, it’s the greenhouse glass!) • Stratosphere: from the top of the troposphere (known as the tropopause) to altitude of 50km. Ozone lives here (well almost all of it). • Mesosphere: from the stratopause (the top of the stratosphere) to altitude of 80km. Coldest temperatures in the atmosphere! • Thermosphere: Almost to the top. The only thing beyond is the ionosphere (aurora borealis zone) and exosphere (transition to space). Nitrogen and oxygen absorb solar radiation here.

15. Greenhouse Gases and the Greenhouse Effect • Greenhouse gases: carbon dioxide, methane, water vapor • Importance of greenhouse gases: these gases help keep some of the radiation from going back to space. They help regulate the temperature of Earth and keep it habitable for life. • Note: Interference from humans can cause increases of greenhouse gases in the atmosphere. When this happens, the Earth may get too hot!

16. Sources of Greenhouse Gases • Naturally through the biochemical cycles (Water cycle, carbon cycle, nitrogen cycle, etc), volcanes, etc. • Human interference through CFC emissions and industrial activities.

17. Atmosphere & Ocean • Oceans cover nearly three-quarters of the earth's surface and play an important role in exchanging and transporting heat and moisture in the atmosphere. • Most of the water vapor in the atmosphere comes from the oceans. • Most of the precipitation falling over land finds its way back to oceans. • About two-thirds returns to the atmosphere via the water cycle. • You may have figured out by now that the oceans and atmosphere interact extensively. Oceans not only act as an abundant moisture source for the atmosphere but also as a heat source and sink (storage).

18. Atmosphere-Ocean • Ocean currents play a significant role in transferring this heat poleward. Major currents, such as the northward flowing Gulf Stream, transport tremendous amounts of heat poleward and contribute to the development of many types of weather phenomena. They also warm the climate of nearby locations. Conversely, cold southward flowing currents, such as the California current, cool the climate of nearby locations.

19. Energy Heat Transfer • Energy is transferred between the earth's surface and the atmosphere via conduction, convection, and radiation. • Conduction:process by which heat energy is transmitted through contact with neighboring molecules. • Convection transmits heat by transporting groups of molecules from place to place within a substance. Occurs in fluids such as water and air, which move freely. • Radiation: the transfer of heat energy without the involvement of a physical substance in the transmission. Radiation can transmit heat through a vacuum.

20. Diagram It!

21. Conduction • Air and water are relatively poor conductors. • Most energy transfer by conduction occurs right at the earth's surface. • At night, the ground cools and the cold ground conducts heat away from the adjacent air. • During the day, solar radiation heats the ground, which heats the air next to it by conduction.

22. Convection • In the atmosphere, convection includes large- and small-scale rising and sinking of air masses and smaller air parcels. • These vertical motions effectively distribute heat and moisture throughout the atmospheric column and contribute to cloud and storm development (where rising motion occurs) and dissipation (where sinking motion occurs).

23. Convection Cells • Convection cells distribute heat over the whole earth. • Consider a simplified, smooth earth with no land/sea interactions and a slow rotation. Under these conditions, the equator is warmed by the sun more than the poles. The warm, light air at the equator rises and spreads northward and southward, and the cool dense air at the poles sinks and spreads toward the equator. As a result, two convection cells are formed. • Meanwhile, the slow rotation of the earth toward the east causes the air to be deflected toward the right in the northern hemisphere and toward the left in the southern hemisphere. This deflection of the wind by the earth's rotation is known as theCoriolis effect.

24. Diagram It!

25. Radiation • Energy travels from the sun to the earth by means of electromagnetic waves. • The shorter the wavelength, the higher the energy associated with it. • Most of the sun's radiant energy is concentrated in the visible and near-visible portions of the spectrum. Shorter-than-visible wavelengths account for a small percentage of the total but are extremely important because they have much higher energy. These are known as ultraviolet wavelengths.

26. 2. Solar System and Universe • Stars: The most important characteristics to know are color, temperature, mass, and luminosity. • Stars are powered by nuclear fusion of lighter elements into heavier elements, which results in the release of large amounts of energy. • Technology has increased understanding of the universe. • Study of the ongoing processes involved in star formation and destructionhelp us to understand what is happening in our Sun. • Scientific evidence suggest that the universe is expanding.

27. Stars: Color and Temperature • Most stars appear white to our eyes, however, the predominant color is dependent upon their surface temperature. • The hotter the star, the more blue light it emits; conversely, cooler stars emit more red light • If different colors are emitted with each about the same intensity, the star will appear white. • Note that these temperatures, though much hotter than what we encounter in our lives, are still quite small compared to the temperature at the star’s core (which can be tens to hundreds of millions of degrees!)

28. Stars: Mass • Mass: the most important characteristic and determines the life span and ultimate fate of a star. • The lower the mass, the longer the life span. The higher the mass, the shorter the life span. • Example: Our Sun, 1 solar mass = 10B years. Another star, 30 solar mass = 15M years • Ultimate fate: Low mass = red giant, planetary nebula, white dwarf. High Mass = Giant/Supergiant, supernova, black hole, neutron star

29. Stars: Luminosity • Luminosity: total amount of energy emitted by star every second. • Diameter and temperature determine luminosity. • Diameter determined by mass. • A star’s luminosity and temperature are frequently plotted on a graph called the Hertzsprung-Russell, or H-R, Diagram. • Temperature (or sometimes its spectral class, which is related) is plotted on the horizontal axis, with the values decreasing to the right. • Luminosity is plotted on the vertical axis, using a logarithmic scale. • When the corresponding values for a large number of stars are then plotted on this graph, groupings of stars can be easily identified, including the main sequence.

30. Nuclear Fusion? • The primary source of energy in our Sun and all stars is nuclear fusion. • Four hydrogen ions (simply protons) are combined through collisions to create one helium ion (containing two protons and two neutrons). • The high temperatures and densities required for nuclear fusion can be found in the cores of stars. • The gravitational attraction between the gas particles pulls them into a very small region and causes them to move incredibly fast.

31. Nuclear Fusion? • The fusion of hydrogen into helium constitutes what astronomers call the star’s “main sequence” lifetime • The most massive stars undergo fusion at an extremely high rate, and so use up their fuel very quickly – thus existing on the main sequence for a shorter length of time than less massive stars. • After the main sequence phase, helium can also undergo nuclear fusion, as can other elements.

32. Space Technology • The telescope is humankind’s single greatest technological step toward understanding our universe. • Galileo: made five important observations that directly contradicted the mythological view of our universe: • discovering that Jupiter has moons that rotate about the planet; • observing that Venus has phases, a finding that could only be explained by 
Venus orbiting the Sun; • discovering that the Moon has mountains, valleys, and craters that are similar
to features on Earth; • observing that the Sun has blemishes (sunspots) and rotates about once 
every month; and • observing that the Milky Way is not a smooth field of light, but is made up
of thousands of stars.

33. Space Technology • Telescopes: • observe light and it is through this light that scientists gather all their information about the universe beyond Earth. • The first telescopes, But visible is only a small part of the entire light spectrum. • In the 20th century, scientists began to use all other frequencies of the electromagnetic spectrum (radio, microwave, infrared, ultraviolet, x-ray, and gamma-ray) • By observing these wavelengths, astronomers were able to discover a vast universe of phenomena, such as black holes, neutron stars, extrasolar planets, and active galaxies.

34. Hubble Space Telescope • Space-based observatories. • No atmospheric filter • Some light frequencies, such as infrared, x-ray, and gamma ray, are only observed from space (or high in Earth’s atmosphere) because these frequencies do not penetrate to Earth’s surface. • Hubble Space Telescope is the most famous and has provided a view of the universe in the visible and ultraviolet light that has not yet been equaled from much larger Earth-based telescopes. • Chandra X-ray Observatory and the Spitzer Space Telescope, have been equally as important to science as Hubble because they provided very high-resolution views of our universe in frequencies outside the visible.

35. Star Life Cycle • http://www.bighistoryproject.com/~/media/Files/BigHistory/Star%20Stages%202012-03-20.pdf • How does this work? Gravity. • A star must maintain equilibrium and offset gravity by the energy that it pushes outward. • Main sequence: A star is fusing hydrogen into helium.

36. Expanding Universe • Early 1920s, an astronomer at Mount Wilson Observatory named Edwin Hubble • Hubble observed that the spectral signatures of almost all galaxies were redshifted, indicating that they were moving away from Earth. • Furthermore, the farther away the galaxy is, the greater its redshift. In other words, galaxies were moving away from Earth at a rate proportional to their distance from us. This relationship is now called Hubble’s Law and is an indication that the universe is expanding.

37. 3. Earth’s Composition & Structure • Diagram

38. Objectives • Objective 1: Students know how successive rock strata and fossils can be used to confirm the age, history, and changing life forms of the Earth, including how this evidence is affected by the folding, breaking, and uplifting of layers. • Explain the basics of the process of fossil formation. • Apply the principles of superposition to relative dating of rock layers. • Describe the process of absolute dating. • Sequence the age, history, and changing life forms of Earth using strata and fossil evidence. • Describe how folding, breaking, and uplifting of strata complicate geological evidence. • Objective 2: Students understand the concept of plate tectonics including the evidence that supports it (structural, geophysical and paleontological evidence). • Describe how convection in Earth’s mantle has changed the locations + shapes of continents based on tectonic plate movement. • Identify the evidence for seafloor spreading. • Identify the three major types of tectonic plate boundaries.

39. Objectives • Objective 3: Students know elements exist in fixed amounts and move through solid earth, oceans, atmosphere and living things as part of biogeochemical cycles. • Explain how matter and energy are transferred chemically through systems that include living and non‐living components. • Objective 4: Students know processes of obtaining, using, and recycling of renewable and non‐renewable resources. • Identify the differences between renewable and non‐renewable resources. • Explain how recycling reduces the rate of depletion of nonrenewable resources. • Identify the processes used to obtain natural resources (e.g., mining, oil production, water, and agriculture). • Objective 5: Students know soil, derived from weathered rocks and decomposed organic material, is found in layers. • Describe the structure of soil, its components, and its formation

40. Key Ideas

41. Fossils • Different rock layers contain different fossils (key to dating the geologic past) • Fossils: the remains of animals or plants that lived in a previous geologic time • Paleontology: the study of fossils • Fossils provide information to the relative and absolute ages of rocks, as well as provide clues to past geologic events, climates, and evolutiom

42. Fossilization • Generally, only the hard parts of organisms become fossils. Fossilization processes are: • Mummification • Amber: hardened tree sap • Tar Seeps • Freezing: almost completely preserved • Petrification: replica of the original organism

43. Fossil Types • Trace fossil: a fossilized mark that formed in sedimentary rock by the movement of an animal on or within soft sediment • Index fossil: fossils that occur only in rock layers of a particular geologic age (used to determine the relative age of rock layers) • Must be present in rocks scattered over a large region • Must have features that clearly distinguish it from other fossils • Organism must have lived during a short span of geologic time • Must occur in fairly large numbers within the rock layers

44. Rock Cycle • Rocks: naturally occurring aggregates of one or more minerals. • Composed of material that has been present on Earth since it first formed – excluding that material which has been delivered by meteorites • Rock Cycle: a model that illustrates the changes to rocks that have taken place through time. • Rocks are recycled into other rocks through processes which occur in mainly two locations; at or near Earth’s surface such as weathering, erosion, and deposition; and deep below the surface such as melting and increased heat and pressure. Most rocks are formed from other rocks and a “rock” may take more than one path through the rock cycle.

45. Diagram It!

46. Rock Cycle and Rock Types • Metamorphic rock: metamorphic rock would need to experience an increase in temperature to the point of melting it, creating magma. • Eventually this magma body would enter an environment where the heat contained would transfer from it (cooling) and the process of solidification (crystallization) occurs. This rock is now classified as an igneous rock. • Igneous rock: several more changes must occur in order to turn this igneous rock into a sedimentary rock. • The igneous rock needs to be subjected to the agents of weathering and erosion, which over geologic time creates pieces or fragments of rock called sediment. As this sediment piles up, compaction and cementation turn the loose sediment into a solid rock through the process of lithification. This rock is now classified as a sedimentary rock. • Continuing clockwise this sedimentary rock will become a metamorphic rock with the addition of heat and pressure causing a partial melting of some of the minerals in the sediment. This process is referred to as metamorphism and results in creation of a metamorphic rock. The straight arrows within the rock cycle diagram indicate that any one rock type can turn into any other rock type by passing through several common processes.

47. Rocks and Minerals • Key Points: • Fossils • Superposition • Absolute dating • Rock Types • Mineral Information

48. External Forces • Processes that wear the Earth’s surface down • 1. Weathering: the breaking down of rocks into smaller pieces (assists in the formation of soil) • Physical weathering • Chemical weathering • 2. Erosion: the process by which rock material at Earth’s surface is removed and carried away • Gravity and water • Glacier • Wind

49. Physical Weathering • Rock is broken into smaller fragments by physical agents • Example: water seeps into cracks, in a rocks and freezes, the water expands, breaking the rock apart • Example: roots of plants growing in cracks can also force rocks apart

50. Check for Understanding