EAS 201 First Midterm

Biosphere

Living Things

Geosphere

the solid earth

minerals, rocks and rock cycle

time

tectonic system (earthquakes, volcanos, and plates

Earth Science Observations

many observations are made outdoors in field investigations

however this is less easy to control than lab conditions

scientists must be selective and focus on data relevant to the ideas being tested

Hypotheses

An idea about how observations are related to each other

statement of how observations can be explained

testable by comparing its predictions with future observations or experiment

Theory

a hypothesis that has survived a number of tests and explains more than just one phenomenon

Scientific Law

A theory or part of a theory that explains many observations and has passed many tests may be trusted to the point

Principle of Stratigraphic Superposition

In any succession of sedimentary strata, the order in which strata were deposited is from the bottom to the top

Useful theory but it isn’t always true as there could be magma that flowed through a crack

Model

Simplified version of the natural world

could be physical or a mathematical algorithm

Paradigm

When a whole branch of science is revolutionized by a new theory that is coupled with new ways of making observations and thinking

factors

Uniformitarianism

Features observed in ancient rocks can be explained by processes operating at the present day

was too strict

Principle of Actualism

The natural laws that allowed the formation of ancient features of the Earth are the same as those in operation today

Present is key to the past

System

A portion of the universe that can be separated from the rest for the purpose of observing and understanding changes

eg Atmosphere, Hydrosphere, Biosphere, Geosphere

systems can exist inside one another

Types of Systems

Isolated

Closed

Open

Isolated System

No matter or energy is lost or gained

imaginary concept

the solar system could be treated as one as not much matter escapes or comes in

Closed System

No matter lost or gained; energy may be exchanged with surroundings

Earth is approximately a closed system as only small amount of gas are lost and tiny amounts of material are added

Open System

Matter and energy are exchanged with the surroundings

atmosphere, ruver, island, forest, body, etc

Cycles

We can trace the flow of energy and material through earth systems by looking at cycles

eg energy, water, carbon, rock cycles

quantfied'= on a budget, eg resovior

Reservoir

Location where a quantity of material or energy sits

Flux

the rate at which material moves from one reservoir to another

eg heat from sun evaporating water from oceans

Largest to Smallest Reservoirs of Water

Oceans

Glaciers and other ice

Groundwater

Surface water on land

Water in the atmosphere

Water in the biosphere

Evaporation

heat from the sun evaporating water from oceans, lakes, rivers, etc

Evapo-transpiration

emissions from water vapor from plants

Water Budget

Flow in and out of each reservoir is roughly constant

Residence time of Water

in a reservoir is the average length of time a water molecule spends there

divide volume of reservoir by the rate of flow in or out

Climate Change Impact of Hydrologic Water Cycle

Flow in, and out of some reservoirs is not equal

reservoir may contract or expand

eg glaceirs are melting faster than they are replaced, and the ocean is expanding

What is included in a solar system

A single star

Numerous objects orbiting the sun

Planets, dwarfs and minor planets, asteroids, meteoroids

Comets

Satellites orbiting planets

Origin of the solar system

Entire solar system condensed from gaseous nebula by gravitationalattraction. Central dense body became sun remaining dust and gas formed disk disk eventually condensed to form planets and other bodies “

Gravity

objects in a solar system are maintained in orbit by gravity

Remain in balance between gravity pulling inward and momentum of the object

Orbits are ellipsis

Gravitational pull varies on distance

Shape of orbits

Ellipse

Sun at one focus

Speed varies faster when closer

Comets

Small bodies in highly elliptical orbits

Comet tail always points away from the sun

Compositions similar to Jovian planets

Asteroids and meteoroids

when they strike earth they become meteors as they burn up in the atmosphere

if a meteoroid makes it to the ground, it is called a meteorite

many are remmnants of plants that broke up or collided early in solar system history

samples early solar systems (chondrites)

chondrites

samples of early solar systems

maybe found in meteorites

Jovian Planets

outer 4 planets are similar in size and probable structure

neptune, uranus, Saturn, jupiter

thick hydrogen-rich atmosphere

liquid hydrogen core

denser rock core

Terrestrial planets

inner 4 planets and Earth’s moon are simialr in size and probable structure

mars, earth, venus, mercury,

Metallic core, mostly iron

denser rocky mantle (silicon, oxygen, magnesium, iron)

Mantle

Denser rocky mantle mostly silicon, oxygen, magnesium, iron

thin rocky crust and is vary variable as it depends on the rock cycle affecting each planet

Venus

almost same size as earth but very hard to study the crust, as the atmosphere is CO2 mostly aso the surface temperature just increases

mostly covered in clouds

Mercury

small planet with weak gravity and no atmosphere

Satellites

Orbit around planets

most are very small compared with the parent planet

the moon is the exception as it is similar to a terrestrial planet

Tilts of the Earths axis

the earths axis is tilted and the north and south pole take turns being tilted toward the sun

currently 23.5 degrees

Solstices

poles are tilted towards/away from the sun

Equinoxes

are when tilt is in parallel to the orbit

tilted parallelly

Precession of Equinoxes (Axial Precession)

Tilt direction rotates relative to elliptical orbit

23 000 year period

moves position of solsitices and equinoxes relative to elliptical orbit

Changes in Obliquity

41 000 year period of wobble from 21.5 degrees to 24.5 degrees and back again

Changes in Eccentricity

orbit shape

100 000 period

varies in degree of 6 ish

circular and most elliptical

Tides

The gravity of moon and lesser extent of Sun generates tides on earth

Spring Tide

full or new moon tides mean very high and very low tides when the moon and sun are in line with each other

if it is right angle to sun it makes less intense tides

Sun

sun is a typical star with a 700 00 km radius

109 times the Earth’s diameter

Electromagnetic Radiation

is the represented as waves

wavelength is inversely related to frequency

Solar Spectrum

radio waves, infared light, visible light, ultra-violet

Energy Cycle

atmospheres

gaseous envelopes that surround planets and other large bodies in the solar system

Mixture of gases and aerosols

Aerosols

liquid droplets, solid particles, that are small enough to remain suspended in the atmosphere

Earth’s Atmosphere

Extends above the land and ocean surface and fades into space between 100-1000km depending on criteria used

supports and protects life, stores moisture and solar energy, and moves earths materials

troposphere

lowest part of the earths atmosphere constantly changes from seconds to months which results in weather

longer term changes from months to billions of years are described as climate

30 years is an average time period for calculating climate averages

Temperature

measure of the average kinetic energy of molecules

Heat

Total kinetic of all molecules in a substances

changes with amount of material

Pressure

Gases are compressible

molecules exert a force on the walls of a container due to collisions

force per unit area

Pressure Variation with Altitude

Gases are very compressible

molecules are forced together by the mass of air above so density and pressure of air decrease with altitude

Isobars

contours of constant air pressure

air tends to flow from regions of high pressure to low pressure which drives winds and weather

Adiabatic

no heat is transferred between the gas and its surroundings

as gas rises in the atmosphere and expands, it does work expanding against the pressure of the surrounding gas; therefore, it cools