STAAR REVIEW Earth and Space Systems. Changes in the Earth Over Time. Weathering- the process of rocks being broken down into smaller pieces. Mechanical Rocks break into smaller pieces by physical means – Water, ice, wind, gravity, organisms & changing temperatures. Chemical
Weathering- the process of rocks being broken down into smaller pieces.
Rocks break into smaller pieces by physical means –
Water, ice, wind, gravity, organisms & changing temperatures
Rocks break into smaller pieces by chemical reactions – Air, water, acid & salts react with minerals in rocks to form new substancesTwo Types of Weathering
Plate tectonics explains the movement of large sections of Earth’s crust called tectonic plates. The force behind tectonic plate movement is thought to be currents of magma flowing in Earth’s mantle.
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.
Pacific Plate is the largest
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.
How do these to systems feed into each other?
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.
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.
Without the carbon and nitrogen cycles, there would be no life on earth!
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.
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.
A lunar eclipse occurs when Earth blocks sunlight from reaching the moon. This puts the moon in Earth’s shadow.
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 23.5oangle.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.
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.
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.
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).
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.
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.
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.
Nebulae are huge clouds of dust and gas. Some scientists think that our solar system was formed from nebula.
Spiral sky in winter than in summer? This is because Earth is tilted on its axis at a 23.5
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!
300,000,000 meters per second is the same as 300,000 kilometers per second.
That’s theSpeed of Light!
In the Hertzsprung-Russell diagram each star is represented by a dot. Stars are plotted by their luminosity (brightness) and surface temperature.
http://www.cet.edu/ete/modules/msese/earthsysflr/rock.html kilometers per second.