8 th Grade Science Content Strand 4

Transcription

1 8 th Grade Science Content Strand 4

2 Lithosphere solid, rigid, rocky divided into plates, sits on top of asthenosphere Includes crust & upper rocky mantle Asthenosphere plastic, flowing, hot, convection currents Upper movable mantle

3 Oceanic crust thinner, more dense, sits lower in the mantle Subducts(sinks) & melts Continental crust thicker, less dense, sits higher in the mantle Rises, buckles & crumbles

4 Faulting tension forces, pulling apart Folding compression forces, squeezing together, no breaks

5 What are convection currents & how do they affect plate tectonics? Heat from the core heats up rocks in the mantle causing them to become less dense and rise up, as the rock hits the rocky mantle it cools becomes more dense and sinks back down Causes lithospheric plates to move like sitting on a conveyor belt

6 What is Pangaea? supercontinent 200 million years ago What are some evidences of pangea? Similar fossils on different continents Fit together like a puzzle Warm weather fossils in Antarctica

7

8 What is a Convergent boundary? come together Compressional forces What forms at an Oceanic- continental convergent boundary? What forms at an Oceanic- Oceanic convergent boundary? oceanic plate sinks & melts to for an ocean trench, & continental volcanoes mountains along the coast Deep ocean trench, under-water volcanic mountains that can rise above sea level to form island arcs What forms at an Continental- continental convergent boundary? Thick continental mountains ranges

9 Divergent Move apart (divide) Tension forces What forms at an Oceanic-oceanic divergent boundary? What forms at a Continentalcontinental divergent boundary? seafloor spreading, mid-ocean ridge, underwater volcanoes Ex. Mid-Atlantic ridge rift valley, flat volcanoes Ex. East African Rift Valley

10 slide past each other Transform boundaries Shearing forces Causes Earthquakes Ex. San Andreas Fault

11

12 Primary waves Faster First to arrive Move back & forth (compressional) Move through solids & liquids Secondary waves 2 nd to arrive Only travel through solids Move side to side Surface waves cause most damage Last to arrive Move up & down Why do waves move faster through solids than liquids? Solids are more dense that liquids and can transfer energy faster Ex. Seismic waves travel faster through the solid crust than through the liquid outer core

13 Cold front cooler temperatures after the front passes, thunderstorms or heavy precipitation Warm front- High pressure Low pressure- Isobars warmer temperatures, light rain clear, sunny Rising pressure : less chance of rain Moisture on the ground cloudy, rainy All fronts are low pressure Moisture rises, falling pressure greater chance of rain lines that connect areas of equal air pressure

14

15

16 Coriolis effect Deflection of wind and weather due to the rotation of Earth

17 Trade winds (easterlies) blow from east to west near the equator below the 30 north latitude line Steer hurricanes northwest Westerlies- blow from west to east above 30 North steer hurricanes northeast

18 Polar jet steam Cold air from north Tropic jet stream Warm air from the south

19 Ingredients for a hurricane Lower air pressure= faster winds Trade winds- move hurricanes to west Westerlies- blow them back to the east Warm water- strengthens hurricanes Cold water- weakens

20 Weakens a hurricane Rising pressure air pressure Cold water Moving over land Strengthens a hurricane falling pressure air pressure warm water

21

22 Causes: Too much CO 2 Burning fossil fuels (coal, oil, natural gas) Deforestation (cutting down trees) Ways to Reduce (conservation): Recycle Walk or ride bicycle Energy efficient appliances Fluorescent bulbs Public transportation Use renewable energy Fuel efficient cars

23 greenhouse effect natural trapping of the Sun s heat by the Earth s atmosphere What are the 3 greenhouse gases *****Carbon dioxide Water vapor methane

24 Renewable Solar-sun wind Hydroelectricwater Geothermalinside earth Biomassrecently living material (trees) Nonrenewable fossil fuels Coal Oil Natural gas metals nuclear (uranium) Alternate Resources nuclear

25 Nitrogen cycle draw & label What is responsible for converting most nitrogen into usable compounds Nitrogen fixing bacteria located in the roots of some

26 What gives off carbon? Plants & animal respiration (cellular respiration), factories, decaying organism, burning fossil fuels (CO2) What takes in carbon? Plants (photosynthesis), absorbed by the ocean

27 Draw the cycle on the front & put the answers on the back

28 Rotation Spin on axis Causes day & night 24 hours Revolution Revolves around the Sun with the axis is tilted at 23.5 degrees 365 ¼ days (year; every 4 years is a leap year The axis is always pointed in the same direction Causes seasons & length of year

29 Solstice Summer solstice: longest day light day of the year June 21 st (northern hemisphere) Sun s rays are at highest angle Sun s rays are most direct over the Tropic of Cancer in the Northern Hemisphere (receive the most energy) North pole receives 24 hours of sunlight Winter solstice: shortest daylight day of the year Dec 21 st (northern hemisphere) Sun s rays are at lowest angle Sun s rays are most direct over the Tropic of Capricorn in the Southern Hemisphere (receive the least energy) North pole receives 24 hours of darkness

30 Spring & Fall Equinox: Equal daylight & darkness Mar. 21 st Spring (Vernal) (northern hemisphere) Sept. 22 nd Autumn (northern hemisphere) Sun s rays are most direct over the Equator (receive the equal amounts energy) Both Poles receives 12 hours of sunlight

31

32 1. During a summer solstice in the Northern Hemisphere which area of earth receives the most day light? 2. Which area receives the most direct energy? #1The north pole receives the most daylight #2 Tropic of Cancer

33 Tropical- near equator warm year round most direct sunlight least amount of temperature variation receive about 12 hours of sunlight year round Temperate- middle latitudes 4 distinct seasons warm summers, cool winters greatest amounts of temperature variations receive varying amounts of sunlight with each season Polar- Short summer & long winter receive 24 hours or darkness or 24 hours of daylight 6 months out of the year

34 Tropical- near equator, warm year round, most direct sunlight Temperate- middle latitudes, warm summers, cool winters Polar- summer temperatures much higher than winter

35 What is the approximate Age of the Universe 13.7 billion years List the hierarchical structure of the universe from Largest to smallest using our address in space Universe, Virgo supercluster, Local Group, galaxy, solar system, Earth What is the name of our galaxy & describe is shape? Milky Way- spiral galaxy Where are we located within our Galaxy? Our Sun is located in a spiral arm about 25,000 light years from the edge

36 Red shift Wavelength gets stretched and becomes longer because the object is moving away from us Blue Shift Wavelength gets compressed and becomes shorter because the object is moving towards us What type of shift do most objects in the universe have and what does this provide evidence for? Red shift Evidence of our universe expanding

37 What type of energy(radiation) do telescopes detect in order to study the universe? All types of electromagnetic radiation form the spectrum Radio, micro, infrared, visible, UV, x- rays, gamma Why do we have to launch telescopes into orbit outside our atmosphere? Our atmosphere traps most of the high energy radiation & distorts the information, so we get a clearer image once we get passed the atmosphere

38 What does the wavelength of a star help us learn? Shorter the wavelength the higher the temperature (more energy)

39 What are natural products? any useful substance found in nature & made by a living organism that is used for technology in the development and commercialization of potentially useful products What are some Examples of natural products? Use of plants to make medicines Use of natural plant resistance to improve crops though selective breeding or genetic engineering (hybrid seeds or plants that are insect resistant) Using renewable resources instead of nonrenewable (faster growing trees for hardwood flooring)