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Ms. Neuner's Science Classes

Environmental Science
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Class Notes for 9/8-9/16

The Earth Within the Universe

I. The Solar System

- our solar system is in the Milky Way galaxy

- the solar system is 6 billion years old

A. The Sun

- the Sun is the star at the center (solar = sun)

- the Sun is the largest body in the solar system

- has a diameter of 870,000 miles (1,390,000 km)

B. The Planets

- there are 10 planets in our solar system as of January 5, 2005

- the first four are classified as the terrestrial planets (Mercury, Venus, Earth, and Mars)

- the next four are classified as the gaseous giants (Jupiter, Saturn, Uranus, and Neptune)

- Pluto is a tiny planet with an irregular orbit

- the new tenth planet is temporarily called 2003 UB313 and is very similar to PlutoC. Other Bodies in the Solar System

- comets are dirty snowballs that travel in orbits around the sun

- asteroids are large boulder- to mountain-sized rocks that are found mainly in a belt between Mars and Jupiter

- meteoroids are rocks that are smaller than asteroids

- called a meteor if it enters Earth's atmosphere and is seen as a streak of light

- if the meteor does not burn up in the atmosphere and crashes into the Earth, it is called a meteorite

II. Planet Earth

- Earth is unique because of its water, oxygen, and nitrogen

A. The Moon

- Earth's only natural satellite is the Moon

- the Moon reflects some of the Sun's light and appears to shine

- amount of light reflected varies, so we see the Moon in phases

- full moon, new gibbous (waning), first quarter, new crescent, new moon, old crescent, last quarter, old gibbous (waxing)

- revolves around the Earth and rotates on its own axis

- always shows the same side to the Earth because the rates of revolution and rotation are the same

- takes 27.3 days to make one complete revolution around Earth

- the Moon affects the ocean's tides

- there are 2 high tides and 2 low tides every 24 hours

- the full moon causes very high tides

B. Time on Earth

- the Earth spins (rotates) on its axis and revolves around the Sun

- one complete turn on the axis is one day (24 hours)

- one complete turn around the Sun is one year (365.4 days)

C. Seasons

- seasons occur because the Earth is tilted 23.5 degrees on its axis

- this tilt allows some areas of the planet to get more sunlight than others

- the equator divides the Earth into the Northern Hemisphere and Southern Hemisphere

- the hemisphere must be tilted towards the sun in order for summer to occur as a result of direct rays

- New York is in the Northern Hemisphere

-first day of winter is on December 21 (winter solstice)

- shortest day of the year with the direct sunlight on the Tropic of Capricorn

- first day of summer is on June 21 (summer solstice)

- longest day of the year with direct sunlight on the Tropic of Cancer

- first day of spring is on March 21 (vernal equinox), and the first day of autumn is on September 23 (autumnal equinox)

- both days have 12 hours of sunlight with the direct rays on the equator

The Anatomy of Earth

I. Overview of Earth’s Composition

- the lithosphere is the outer layer of the Earth (the crust)

- the crust is made up of rock, soil, and some common elements (O2, Si, Al, Fe, Ca, Na, K, Mg)

- 71% of the crust is covered with water

- all areas of water make up the hydrosphere

- the atmosphere is made up of gases that sit on the crust (78% N2, 21% O2, 1% Ar, CO2, H2O)

- the core of the Earth is molten and made out of Fe and Ni

- the core is denser than the lithosphere

II. The Crust

- made of minerals like gold, copper, carbon, feldspar, mica, quartz, and calcite

- minerals can form crystals if they are changed by heat and pressure

- igneous rocks are made when magma cools

- magma can also flow out of the crust as lava

- sedimentary rocks are made of particles that become cemented together

- metamorphic rocks are made when existing rocks are changed by heat and pressure

A. The Continents

- at the present, there are seven continents (Africa, Asia, Europe, Australia, Antarctica, North America, South America)

- in 1912, Alfred Wegener proposed that there was once one giant continental landmass called Pangaea

- Pangaea means all Earth

- continental drift caused Pangaea to break up into pieces and move on the crust

- Gondwanaland was in the south, and Eurasia was in the North

- theory was proven to be correct because of the puzzle-like fit of Africa and South America, the similarities of rock formations, and similarities of fossils in both continents

- Wegener’s theory was not accepted until the 1960s

- ridges and cracks were found in the sea floor

- magma flowed out of the Earth and widened the sea floor, pushing the continents apart

B. Crust Under the Sea

- the mid-ocean ridge is the largest mountain chain on Earth

- there are rift valleys

- the sea floor surfaces to form volcanoes

- there are faults (cracks) in the sea floor where movement occurs

- the farther away from the mid-ocean ridge a rock is, the older it is

- new magma flows out of the faults and pushes the old rocks away

- old rocks are pushed into deep trenches in the crust and may melt (subduction)

- the deepest trench in the world is the Mariana Trench

- a series of trenches in the Pacific Ocean make up the Ring of Fire, an area of immense volcanic activity

C. Plate Tectonics

- the continents and the sea floor rest on plates

- plates are large pieces of crust that float on the mantle

- there are 12 very large plates and several smaller ones

- the continental plates are lighter than the sea floor plates

- the plates move constantly

- volcanoes form when the sea floor plates push under the continental plates

- mountains form when continental plates collide

- areas known as transform boundaries where there is a lot of plate movement are earthquake sites

- the plates grind together, as on the San Andreas fault line

D. The Future of the Earth’s Crust

- the Atlantic Ocean will become wider, whereas the Pacific Ocean will become narrower

- Africa will move north

- the Mediterranean Sea will dry up

- a new mountain range will stretch from Africa to Turkey when African crashes into Asia

- Australia will move north

- California will separate from North America and become a series of islands

 

St. Edmund Preparatory HS Science