Chemical Weathering
* rain water reacting with the mineral grains in rocks to form new minerals (clays) and soluble salts. These reactions occur particularly when the water is slightly acidic (changes in their chemical composition, ex. change in paper after being burned)
Earth's Basic Structure
Core, Mantle, Crust
Physical Weathering
*caused by the effects of changing temperature on rocks, causing the rock to break apart. The process is sometimes assisted by water. (freeze-thaw, ex. ripping piece of paper-changes size, still paper)
Magnetic Field
It's thought that the Earth's magnetic field is generated by the molten iron core at the centre of the planet. The molten iron has currents of its own, just like an ocean, and these moving currents create the magnetic field
Sedimenatary Rock
formed from particles of sand, shells, pebbles, & other fragments of material. Accumulates in layers, over time hardens, fairly soft, easily crumbles. ONLY type that contains fossils (usually) Ex. conglomerate & Limestone
Metamorphic Rock
formed under the surface of the earth from the metamorphosis (change) that occurs due to intense heat and pressure (squeezing). Ribbon-like layers, shiny crystals. Ex. gneiss & marble
Igneous Rock
formed when magma (molten rock deep w/in earth) cools & hardens. Magma cools inside earth, as well as erupts onto the surface (volcano lava). Lava cools quickly, no crystals form, rock looks shiny & glasslike or gas bubbles leave holes in rock. Ex. basalt
Minerals
Geologists define a mineral as: A naturally occurring, inorganic, solid, crystalline substance which has a fixed structure and a chemical composition which is either fixed or which may vary within certain defined limits.
Weathering
The breakdown of rocks at the Earth's surface, by the action of rainwater, extremes of temperature, and biological activity.
3 types of weathering, physical, chemical and biological.
Erosion
Erosion is the process by which soil and rock particles are worn away and moved elsewhere by wind, water or ice.
Deposition
sediment settles out of the water or wind that is carrying it, and is deposited in a new location. Carried by wind, water, or ice. Sediment can be transported as pebbles, sand & mud, or as salts dissolved in water.
Plate Tectonic Theory
Plate tectonics is the theory that the outer rigid layer of the earth (the lithosphere) is divided into a couple of dozen "plates" that move around across the earth's surface relative to each other, like slabs of ice on a lake.
The Water Cycle
Importance of Fossils
Fossils are the result of dead animals and plants being preserved, which is usual in most places and times. They are important because they show the types of animals and plants that were on the earth at different times in the past.
Rock Record
the rocks that currently exist. The rock record does not show an orderly progression of geologic events. Rock formations are eroded, buried, torn apart, melted, squashed together, even turned upside down. The only parts of the Earth history "recorded" are
Waves
transfers energy from one place to another. Oceans/large lakes they are caused by wind blowing over the surface of the water. (size determined by how far, fast, long wind blows)
Currents
the horizontal, unidirectional flow of water. Influenced by the weather in coastal areas. Scientists tract them by releasing floating buoys and track their positions.
Tides
rise and fall of sea levels caused by the combined effects of gravitational forces exerted by the Moon, Sun, and rotation of the Earth.
Oceans
1. Pacific - largest
2. Atlantic
3. Indian
4. Southern
5. Arctic
How Tides Work
Factors: Moon, Sun, Earth & gravitational pull
-Moon is biggest factor, assert gravitational pull on earth
-moon pulls oceans=high tide
-Low tide on opposite sides
Seas
- small than oceans
- salt water
- somewhat surrounded by land
- Mediterannean, Baltic, Caspian, Coral, Carribbean
Lakes
Bodies of water in a depression on earth's surface (ex. great lakes- HOMES- Huron, Ontario, Michigan, Erie, Superior)
Stream
A flow of water in a channel or bed, as a brook, rivulet, or small river.
River
Formed by runnoff, rain, or snow. Channeled flow of water, starts as a spring or stream. Flows higher to lower, empties into stream or ocean. (ex. Amazon, Arkansas, Nile, Ganges, Mississippi)
Polar Ice Caps
dome-shaped sheets of ice found near the North and South Poles. They form because high-latitude polar regions receive less heat from the sun than other areas on Earth. As a result, average temperatures at the poles can be very cold
Iceburg
a large floating mass of ice detached from a glacier or ice sheet and carried out to sea.
Glacier
a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles.
Groundwater
the water located beneath Earth's surface in soil pore spaces and in the fractures of rock formations. Found underground in cracks and spaces in soil, sand and rocks.
Earth's Atmosphere
a mixture of nitrogen (78%), oxygen (21%), and other gases (1%) that surrounds Earth. 5 layers (Troposphere, Stratosphere & Ozone Layer, Mesosphere & Ionosphere)
Hurricanes
huge storm up to 600 miles across with strong winds spiraling inward and upward at speeds of 75 to 200 mph. Moves 10-20 miles per hour over the open ocean. Gathers heat and energy through contact with warm ocean waters.
Clouds
a visible mass of condensed water vapor floating in the atmosphere, typically high above the ground.
Precipitation
any form of water - liquid or solid - falling from the sky. It includes rain, sleet, snow, hail and drizzle plus a few less common occurrences such as ice pellets, diamond dust and freezing rain.
Solar System
Asteroid
a small rocky body orbiting the sun. Large numbers of these, ranging in size from nearly 600 miles (1,000 km) across (Ceres) to dust particles, are found (as the asteroid belt ) especially between the orbits of Mars and Jupiter, though some have more ecce
Comet
a celestial body that appears as a fuzzy head usually surrounding a bright nucleus, that has a usually highly eccentric orbit, that consists primarily of ice and dust, and that often develops one or more long tails when near the sun.
Galaxy
a system of millions or billions of stars, together with gas and dust, held together by gravitational attraction. (Sun belongs to galaxy milky way)
Seasons
Earth's seasons are because of its axis. Winter certain hemisphere's axis are tilted away from the sun. Summer certain hemmisphere's axis are tilted towards sun.
Lunar Eclipse
an eclipse in which the moon appears darkened as it passes into the earth's shadow (umbra). Happens at least 2x/year
Star
A huge ball of gas held together by gravity. The central core of a star is extremely hot and produces energy. Some of this energy is released as visible light, which makes the star glow.
Universe
all existing matter and space considered as a whole; the cosmos. The universe is believed to be at least 10 billion light years in diameter and contains a vast number of galaxies
Black Hole
A black hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.