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Objective 5 Earth and Space Systems Middle School Science Science STAAR Need to Know 1 Changes in the Earth over time Weathering- the process of rocks being broken down into smaller pieces. 2 Two types of Weathering Mechanical Rocks break into smaller pieces by physical means – Water, ice, wind, gravity, organisms & changing temperatures Chemical Rocks break into smaller pieces by chemical reactions – Air, water, acid & salts react with minerals in rocks to form new substances 3 Erosion Destructive The movement of particles from one location to another is erosion Weathered particles of rock are transported by gravity, living organisms, water, glaciers & wind. TAKS Need to Know 4 Deposition Constructive The settling (depositing) of eroded particles as sediments wherever they are transported by wind or water. TAKS Need to Know 5 TAKS Need to Know 6 WHO: Alfred Wegener Proposed that Earth’s continent were all joined in a single land mass called PANGAEA, which means “All land” 7 Fossil Clues: A. fossils of Messosaurus (dinosaur) found in South America and in Africa. Lived in freshwater and on land – continents separated by salt water – no way it could swim from one to the other. B. Glossopteris (plant) fossil found in Africa, Australia, South America, and Antarctica. So many different areas and climates. 8 Climatic Clues – fossils of warm weather plants found on island of Spitsbergen in Artic Ocean, Evidence of Glaciers in temperate and tropical areas 9 Rock Clues – similar rock structures found on different continents showing similarities – East South America and West Africa coastlines have same rock structure 10 11 Plate Tectonics The force behind tectonic plate movement is thought to be currents of magma flowing in Earth’s mantle. TAKS Need to Know 12 Plate boundaries Tectonic plates slowly collide against one another along plate boundaries. Sections of the plates may break off and be pushed down, up, or to the side. Mountain ranges, ocean trenches, earthquakes & volcanic activity are all common along plate boundaries. TAKS Need to Know Pacific Plate is the largest 13 14 A map that shows the shape and elevation of the land surface using contour lines , and shows other land features using symbols and colors 15 The most important thing to remember is that CLOSE contour lines mean STEEP terrain and OPEN contour lines mean FLATT terrain. 16 Neap Tides occur during quarter moons, produce an especially weak high tides 17 Spring tides are especially high tides, occur when Earth , sun and moon are lined up – occur during full and new moons 18 TAKS Need to Know 19 20 Warm Front – when warm air advances into a region of colder air – warm air mass slides up and over the cold air mass. Produces long period of steady precipitation over a wide area. After front passes the skies clear , wind direction changes and temperature rises. Cold Front – occurs when cold air mass advances and pushes under a warm air mass. Warm air is forced up. Produces short periods of storms with heavy precipitation. After front passes, winds change direction, skies begin to clear and 21 temperature usually drops Stationary Front – occurs where a warm air mass and a cold air mass meet but neither advances. Produces cloudiness and steady precipitation. Occluded Front – occurs when a fastmoving cold front overtakes a slower moving warm front, produces cloudy weather with precipitation 22 High Pressure - Winds blow outward, clock-wise; air pressure is highest at center – usually bring clear skies and fair, cool weather Low Pressure – Winds blow inward toward center, counterclockwise; air pressure is lowest at center – usually brings cloudy skies, precipitation and warm weather 23 Provides energy that drives convection in the atmosphere and oceans which causes weather Produces wind and ocean currents. 24 TAKS Need to Know 25 All the land that drains into a specific body of water. Groundwater and surface water both contribute to the water in a watershed. Surface water becomes groundwater by soaking into the sand and soil or by traveling through cracks in rock. TAKS Need to Know 26 TAKS Need to Know 27 Two important ways that oceans affect climate on land 1. Land heats up faster than water because land has a lower specific heat than water does. This causes the air over land to heat faster than the air over water. The warm air rises, starting a convection current that pulls air toward land from the ocean. This keeps air over the land from getting too hot and brings moist ocean air inland. 2. Warm air holds more water vapor than cold air does. When warm, moist air is cooled, clouds form and can produce precipitation. This warm air can be cooled by rising into the colder upper atmosphere, by moving over cold ocean or lakes, or by mixing with colder air. (Ex. Front boundary- the edge where cool, dry air meets warm, moist air. Often causes stormy weather) TAKS Need to Know 28 Nitrogen Cycle Nitrogen changes back & forth from nitrogen gas to the nitrogen compounds used by plants & animals. Nitrogen is passed from plants to other organisms through food webs in the ecosystem. Once plants & animals use the nitrogen it returns to the atmosphere as a gas, completing the cycle. Some fertilizers contain nitrogen compounds because plants need nitrogen to grow. Though there is plenty of nitrogen gas in the atmosphere, plants can’t use this form. In nature nitrogen can be changed from a gas to a form that plants can use by lightning or by soil bacteria and fungi in a process called nitrogen fixation. 29 Problems if too much Nitrogen in environment 30 Carbon Cycle TAKS Need to Know 31 TAKS Need to Know 32 33 Effects of carbon on environment One of the biggest ways humans affect the carbon cycle is by burning fossil fuels. Burning fossil fuels transforms carbon into carbon dioxide. Higher levels of carbon dioxide cause the atmosphere to hold more heat energy. This may be the cause of warmer temperatures measured in recent years on Earth. (Called “The Greenhouse Effect”) This could affect the climate in many places. The kinds of plants and animals in these climates may change if the warming continues. 34 Without the carbon and nitrogen cycles, there would be no life on earth! 35 Catastrophic events affect the earth 36 Ways humans affect the earth Two common forms of pollution: 1. Gases released into the atmosphere 2. Chemicals that are carried by water into a watershed TAKS Need to Know 37 Humans can cause extinctions Human can change: •The quality of the air, water & soil we use •Ecosystems by removing plants & animals & by introducing new species, such as invasive plants & pets •Invasive species don’t naturally live in the ecosystem where they are introduced. •Invasive species compete with/or drive out native species (species that live naturally in an ecosystem) FIRE ANTS- invasive species- accidentally introduced to North America from South America. They have few predators in NA & aggressively attack & kill many kinds of native plants & animals. They have upset the balance of ecosystems in many southern states. 38 Eclipses TAKS Need to Know 39 Solar eclipse When the moon is aligned so that its shadow falls on Earth’s surface, the sun’s light is blocked from reaching part of the Earth. Called solar eclipse because it’s the sun that is being blocked from our view. TAKS Need to Know 40 Lunar Eclipse A lunar eclipse occurs when Earth blocks sunlight from reaching the moon. This puts the moon in Earth’s shadow. 41 4 main Phases of the Moon TAKS Need to Know 42 Moon phase diagram TAKS Need to Know 43 44 Moon’s Revolution & Rotation 45 Have you ever noticed that the sun travels lower across the sky in winter than in summer? This is because Earth is tilted on its axis at a 23.5o angle. Seasons During winter part of Earth tilts away from the sun. This causes the sun’s rays to strike that part of Earth at a lower angle than in the summer. 46 Seasons- Remember it’s the TILT of the Earth that causes the seasons 47 Winter Solsticeshortest day of the year Days are shorter & nights are longer during winter. This occurs in December in the Northern Hemisphere & in June in the Southern Hemisphere. Each hemisphere receives less sunlight & therefore less heat energy during the winter. This is why temperatures are colder during winter. 48 Summer Solsticelongest day of the year This occurs in June in the Northern Hemisphere and in December in the Southern Hemisphere. Earth’s revolution around the sun causes part of the Earth to tilt toward the sun at different times of the year. This causes that part of the Earth to receive more sunlight at a more direct angle. This is why days are longer and nights are shorter. 49 Equinox Equinox- means “Equal Night” Daytime lasts exactly as long as nighttime on the first day of autumn – the Autumnal Equinox (about September 21) and the first day of spring the Vernal Equinox (about March 21). 50 The Sun & Gravity 51 The Sun is a Star Our sun is a medium-size yellow star. In the sun, hydrogen undergoes nuclear fusion, a process that releases vast amounts of energy. During fusion hydrogen atoms join to form helium atoms. Hydrogen fusion is the source of light, heat, and other radiation from the sun. 52 Comets Comets are made of various solids (like dirt & dust) and ice crystals. When their orbits take them close to the sun, dust and ice heat up to produce a “tail” behind the comet. Larger comets may even become visible without the aid of a telescope. 53 Asteroids Asteroids are rocky and usually follow regular orbits around the sun. Asteroid belt- the area between Mars and Jupiter that contains many asteroids orbiting the sun. 54 Nebulae Nebulae are huge clouds of dust and gas. Some scientists think that our solar system was formed from nebula. 55 Galaxies are groups of millions or billions of stars. The galaxy we live in is the Milky Way galaxy and has over 100 billion stars. It would take 100,000 light years to travel across it! 56 300,000,000 meters per second is the same as 300,000 kilometers per second. That’s the Speed of Light! 57 58 Based on the speed of light and is a measure of DISTANCE not TIME 9.5 X 10¹² Km/yr 59 Gravity is the force that governs motion of our solar system. 60 Closest star to Earth (besides the Sun) Proxima Centauri is the nearest star to our Solar System. Traveling at the speed of light, it would take about 4 years & 3 months to reach it from Earth. (That makes it about 280,000 times farther away from Earth than our sun!) 61 H-R Diagram In the Hertzsprung-Russell diagram each star is represented by a dot. Stars are plotted by their luminosity (brightness) and surface temperature. TAKS Need to Know 62 A huge, slowly-spinning tropical storm that forms over water and has winds of at least 119 km/hr (78 mph) 63 Recipe to start development of a HURRICANE!! 1.Water temperature 80 ̊ F or 26 ̊ C and up to 150 feet deep 2.Low Air Pressure 3.High Moisture content 4.Warm water mixes with warm air makes heat build up quickly 5.Winds move into storm center from High Pressure areas 6.Thunderstorms 64 June 1st through November 30th Warm Temperatures, clear skies and calm conditions Atlantic ocean – start in warm waters off west coast of Africa and travel W/NW towards United States 65 Hurricane Development 1.Tropical Disturbance 2.Tropical Depression 3.Tropical Storm 4.Hurricane 66