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Grade 8 Earth Science.

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Presentation on theme: "Grade 8 Earth Science."— Presentation transcript:

1 Grade 8 Earth Science

2 Chapters 14 & 16: Atmosphere & Climate

3 Composition of Earth’s Atmosphere

4 Layers of Earth’s Atmosphere

5 Info. Relating to the Atmosphere
Troposphere- Ionosphere- Where does weather occur? Why does the frequency of radio stations break up?

6 Ozone Layer What is ozone? What is the ozone layer?
Where is the ozone layer located? How does ultraviolet radiation affect you? Describe CFC’s (chlorofluorocarbons)…

7 Energy From the Sun Type of Energy Transfer Description Example
Radiation Transfer of energy through electromagnetic waves Conduction Transfer of energy that occurs when molecules bump into one another Convection Transfer of heat by the flow of heated material

8 Water Cycle Words to Know
What is a cycle? Evaporation- Transpiration- Condensation- Precipitation-


10 Movement of Air Winds are caused by the uneven heating between the Equator & the Poles Hot air rises Cool air settles Coriolis Effect: deflects all free-moving objects (such as air and water) to the right north of the equator and left to the south

11 Wind Systems The Prevailing Winds are caused by the rotation of the earth and the position of the continents. SURFACE WINDS Easterlies – Westerlies - Trade Winds – Doldrums -


Jet Stream – winds at high altitude (where the jets fly). Flows from west to east in northern hemisphere and opposite direction in the southern hemisphere Local Winds – are caused by convection currents examples are Sea and Land Breezes

14 Climate Words to Know: Tropics- Polar Zones- Temperate Zones-

15 What is the difference between weather & climate?

16 El Nino ~ La Nina Some climatic changes last longer than a season…
El Nino is a climatic event that starts in the tropical Pacific Ocean and sets off changes in the atmosphere (unusually warm ocean temperatures) La Nina is El Nino’s counterpart which causes unusually cold ocean temperatures

17 Climatic Changes Greenhouse Gases- Global Warming (Climate Change)


19 How do oceans affect you? How do you affect oceans?
Chapter 17: Ocean Motion How do oceans affect you? How do you affect oceans?

20 Composition of Oceans Earth’s surface is ______% ocean.
_________ is a measure of the amount of solids dissolved in seawater. It has remained nearly ____________ for years.

21 Elements & Compounds in Ocean Water

22 Surface Currents Move water horizontally Parallel to earths surface
Powered by winds Importance: distribute equatorial heat to other areas of earth

23 The Gulf Stream

24 Upwelling & Density Currents
Circulation of ocean that brings deep, cold, nutrient-rich water to the surface TOP to BOTTOM Important for fishing! Contributes to San Francisco’s “famous fogs” More dense seawater sinks under less dense seawater HORIZONTAL

25 Ocean Waves & Tides Wave- rhythmic movement that carries energy through ________ or _______ Ocean Waves carry energy through _________

26 Breaker- collapsing wave onto the shore

27 TIDES Tide = ______ and ______ in sea level Tidal Range =
the difference between the level of the ocean at ______ _______ and ______ _______ Tides are affected by the gravitational pull of the _______ and _____ on the earth’s waters. The moon is closer to earth, and therefore, exerts a _________ gravitational pull.

28 How Tides Work…

29 Tapping Tidal Energy A Tidal Dam Works Well…
A Tidal Dam Creates Problems…

30 Oceanography- Chapter 18

31 The Seafloor Ocean Basin Features Continental shelf-
Continental slope- Abyssal plains- Plate Boundary Structures Mid ocean ridge- trench


33 Mining the Ocean Floor Salt has always been collected from the ocean water. Now, we also collect oil, gas & minerals from the sea.

34 Life in the Ocean Energy Relationships: - photosynthetic organisms capture the sun’s energy and make food using light energy, carbon dioxide, and water through _______________ - chemosynthetic organisms do not rely on sunlight; instead, they rely on ____________


36 Ocean Life PLANKTON NEKTON BENTHOS -Tiny marine algae & animals
-drift with currents -actively swim -plants, algae & animals that live on the lowest levels of the ocean Examples:


38 Pollution & Marine Life

39 Chapter 22: Sun-Earth-Moon System
ASTRONOMY!!! Chapter 22: Sun-Earth-Moon System

40 Planet Earth Data Sphere: round, 3-D object whose surface at all points is the same distance from its center Axis: imaginary line around which earth spins Rotation: spinning of Earth on its axis causes day & night 1 rotation takes 24 hours


42 Earth’s Magnetic Field

43 Earth’s Revolution Revolution: yearly orbit around the sun
Earth’s orbit is an ellipse (NOT “circle” or “eclipse”) Revolution around the sun takes 365 days

44 SEASONS Earth’s TILT on its axis causes the seasons
Hemisphere tilted toward the sun receives more hours of sunlight & direct rays

45 Equinoxes & Solstices

46 Earth’s Moon The moon rotates on its axis and revolves around the earth once every 27.3 days. Because these two motions take the same amount of time, we only see ONE side of the moon.

47 Moon Phases Moon Phase: apparent change in the shape of the moon as seen from earth Depends upon the relative positions of the earth, sun and moon WAXING = more of the moon becomes visible WANING = less of the moon becomes visible



50 Solar Eclipse- moon comes between the earth & sun, casts a shadow on earth

51 Lunar Eclipse- earth comes between the moon & sun, blocks sunlight from reaching moon

52 The Solar System Collection of planets & other objects that orbit the sun Inner Planets (rocky, solid core) Outer Planets (gaseous)

53 # of Earth Days to Orbit the Sun
The Inner Planets Size & Composition Atmosphere Temperatures Surface Features Moons (number/names) # of Earth Days to Orbit the Sun

54 # of Earth Days to Orbit the Sun
The Outer Planets Size & Composition Atmosphere Below the Atmosphere Notable Features Moons (number/names) # of Earth Days to Orbit the Sun

55 OTHER OBJECTS IN SPACE Comets (Cupids, Donner, Blitzen) orbit the sun
Composed of dust and rock particles mixed in with frozen water and gases. The most well-known comet is Halley’s Comet. It is visible on Earth every76 years.

56 Meteors Meteoroids - A large rock traveling through space, composed of nickel and iron. Meteor – A meteoroid that reaches the earth’s atmosphere. AKA: “shooting star” Meteorite – A meteor that hits the earth’s surface

57 Asteroids – are pieces of rock that orbit the sun between Mars and Jupiter (The Asteroid Belt)… What are they doing there?

58 Stars and Galaxies Chapter 24

59 Constellations Constellations – groups of stars that form patterns that look like familiar objects or characters Modern astronomers have divided the sky into 88 constellations

60 Polaris is the North Star
Circumpolar Constellations 5 constellations that circle Polaris and are visible all year long in the Northern Hemisphere

61 Magnitude Apparent Magnitude Absolute Magnitude
Measure of the amount of light received by earth Absolute Magnitude Measure of amount of light actually given off by a star

62 Distance to Stars Parallax Light Year
Apparent shift in the position of an object when viewed from 2 different positions Light Year Distance light travels in 1 year Light travels FAST (300,000 km/s)

63 Star Temperature

64 The Sun STATS: Layers & Atmosphere Average, middle-aged, yellow star
Produces energy by fusing hydrogen into helium in its core Layers & Atmosphere Photosphere Chromosphere corona

65 Features of the Sun Sunspots, prominences, flares
All caused by the intense magnetic field of the sun

66 H-R Diagram

67 Evolution of Stars


69 GALAXIES: large group of stars, gas, & dust held together by gravity
Elliptical Spiral Irregular

70 The Milky Way What you know as HOME Spiral galaxy

71 Doppler Shift The Doppler Shift causes wavelengths of light coming from galaxies to be compressed or stretched Used to determine whether objects are moving toward or away from the earth Red Shift (appear to move away) Blue Shift (appear to move toward object)


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