Ch 1esnew

Introduction to Earth Science

Chapter 1

Biogeosciences

Earth sciences today incorporates biology.Some once thought to be inorganic processes

may in fact be geochemical……….Bacteria have been found everywhere there is

water, including the tiny pore spaces between mineral grains. Many minerals are made by biological processes.

Find some examples…………EXTRA CREDIT OPPORTUNITY

Earth Science is………

The name for the group of sciences the deals with Earth and its neighbors in space.

1. Geology – “study of Earth”

a. physical geology – includes the materials and processes that shape the Earth.

b. historical geology – tries to establish a timeline for the vast number of physical and biological changes that have occurred in the past.

Oceanography – integrates chemistry, physics, geology, and biology.

a. Composition and movements of seawater, coastal processes, seafloor topography, and marine life

Meteorology – The composition of Earth’s atmosphere.

a. Earth’s motions and energy from the sun cause the atmosphere to produce different weather conditions. This in turn, creates the basic pattern of global climates

Astronomy – is the understanding of Earth’s position in the universe.

a. Learning about other members of our solar system and the universe may help us understand Earth.

How do you think the Earth formed? Catastrophic – The earth formed rapidly in

a series of “catastrophic” events. This occurred approximately 4.56 billion

years ago………What are some catastrophic events?Volcanic events, earthquakes, tsunami,

asteroid impacts.You must ask yourself… What kind of impact

do these events have?

Another Possibly

Uniformitarianism – The earth formed over a long period of time through the geologic process at work in the world today…….

Plate tectonics or continental drift is a example of a slow continuous process.

As It Turns Out

Both theories were part correct….

The earth probably did form quickly, but cooled slowly and continuously since that time.

A Closer Look… at the Solar System.. Protoplanet Hypothesis

What kinds of things does the solar system have in common..

1. All planets orbit the sun in the same direction (counter-clockwise)

2. Most planets have moons that orbit their planets in the same direction (counter-clockwise)

3. Most planets rotate the same direction (counter-clockwise)

4. The sun rotates in the same direction as the planets rotate

What does all this mean?

Formation of Earth

Nebular hypothesis – suggests that the bodies of the solar system evolved from an enormous cloud called the solar nebula.

This cloud was made of mostly hydrogen and helium with a small percentage of heavier elements

What Happened Next….

High temperatures and weak gravity characterized the inner planets. As a result they could not hold onto the lighter gases in the nebula.

The lighter gases hydrogen and helium were whisked away to toward the heavier planets by the solar wind.

Earth, Mars, and Venus were able to hold some of these heavier gases including water vapor and CO2

The outer planets have water vapor, CO2, ammonia, and methane.

Earth’s Place in the Universe

In the 1900s Edwin Hubble demonstrated that the Milky Way is one of perhaps hundreds of billions of galaxies in the universe.

How old is our universe?

Between 13 & 14 billion years old

How do we think the universe formed? It formed from a dense, hot mass that

violently exploded. Within seconds the temperature of the

expanding universe cooled 10 billion degrees.

Basic atomic structures formed like protons and neutrons.

After a few minutes simple atoms of hydrogen and helium formed.

Layers form on Earth

Shortly after the Earth formed radio active elements combined with heat released from colliding particles, produced some melting of the interior.

This allows heavier elements like iron and nickel to sink.

The lighter rocky components floated to the surface.

This differences in density allowed a layering to occur with each layer having its own properties.

Gases escaped the surface much like with volcanic eruptions today.

The atmosphere as well as the oceans formed from gases that were released from within the the Earth.

Earth’s Major Spheres

1. Hydrosphere

2. Atmosphere

3. Geosphere

4. Biosphere

Hydrosphere

All the water on the Earth 97% of all water is salt water 3% is freshwater

– 2% of the freshwater is locked up in ice– 1% of the freshwater is usable

Atmosphere

90% is within 16 kilometers of the surface Importance:

– Breathable air– Protection from the sun’s intense heat and

radiation– Weather and climate patterns– Weathering and erosion

Geosphere

Is not uniform, is divided into three main parts based on composition– Crust – (lithosphere) least dense layer.

• Continental crust

• Ocean crust

• Asthenosphere – partially molten, this allow the pieces of the crust to flow

– Mantle

– Core – most dense layer• Outer core

• Inner core

Biosphere

It extends from the ocean floor to several kilometers above the Earth’s surface

Plants and animals depend on this biosphere Organisms help maintain and alter their

physical environment

A Dynamic Planet

Earth’s ever changing surface Two types of forces

– Destructive forces - weathering and erosion– Constructive forces – volcanism and mountain

building

Plate Tectonics This theory provided scientists with a model to

explain how earthquake and volcanic eruptions occur. How continents move.

The lithosphere is broken into sections called plates.

The plates move as a result of unequal distribution of heat within the Earth.

This movement of the plates generates earthquakes, volcanoes, and forms mountains.

Plate Tectonics

There are two types of forces that affect the Earth’s surface.

1. Destructive forces – like weathering and erosion. These forces tend to flatten the surface of the Earth

2. Constructive forces – volcanism and mountain building. These build up the surface of the Earth and in some cases from new land. These forces are driven by the Earth’s internal heat.

The Model

The theory that emerged, called plate tectonics, provided geologists with a model to explain how earthquakes and volcanic eruptions occur and how continents move.

Representing Earth’s Surface

How do we determine our location on the Earth?

We use 2 measurements

1. latitude - is the distance north or south of the …………..

equator and is measured in degrees

2. longitude – is the distance east or west from the

prime meridian and is measured in degrees

Lines of latitude and longitude form a global grid.

The Need for Maps……..

Globes are great, but………

Maps – are flat representations of the Earth’s surface.

No matter what kind of map is made, some portion of the surface will always look to small, to large, or out of place.

Map makers have found ways to limit the distortion.

Mercator Projection

Geradus Mercator, (1569)

His map was designed for use by sailors. It is great for navigation, but distorts sizes of landmasses.

Robinson Projection

Widely used Shows most distances and sizes without

much distortion

Conic Projection

Only the lines that touch the cone are accurate.

Good for making road and weather maps

Gnonomic Projection

Distances and directions are distorted

Good for short or straight line navigation at sea and when flying.

Topographic map

Represents the three dimensional Earth on a two dimensional map.

These maps show elevation by means of contour lines.

Topographic map terms

Contour interval – determines the distance between contour lines.

Index contour – darker in color they represent 100s of feet

Scale – distance measure made to scale with the land surface

Depression – a hole in the ground Declination – difference between true north and

magnetic north

Topographic Maps

Are designed to show the “ relief “ of the land ( shape of the land ).

They are made to a scale.Smaller scaled maps show

greater detail

Maps Scale

Map scale is a ratio

1:52000 means?1 inch on the map = 52000 inches on

the ground

Map Scale

Topographic Map ColorsBrown - Contour lines

Thick Brown - Index contour lines

Black - Man made objects

Green - vegetationRed - some roads

Blue - water

Contour lines

Vegetation

Road

Man made

Water

STEEP SLOPE

GRADUAL SLOPE

Hill top

Hill top

Valley

ValleyValley

Actual surveyed spotgives latitude, longitude and elevation abovesea level

Map Scale

Tenths of a mile0

Declination

the angle of difference between magnetic north and true north.

Contour linesThe distance between

contour lines is the contour interval.

It is printed under the map scale on the bottom- center of each map.

They are measured from sea level

Calculating average slope

Ave. slope = change in elevation (ft.) distance (mi)

Ave. slope = 1060 ft – 960 ft = 100ft = 25 ft/mi 4 mi 4 mi

1210 ft.1160 ft. south or S-E

144.4 ft./mi.

Steep slope

1190 ft.

S-E

1170 ft.

1270 ft.

920 ft.

Geologic Maps Show types and ages of rocks exposed on

the Earth’s surface.

Advanced Technology

Satellites for remote sensing, GPS devices, etc.

Earth System Science

The Earth is seen as being dynamic planet with separate but interactive parts or spheres which are also interconnected.

Each interactive and interconnected sphere is a subsystem…..

EX: geology, physics, chemistry, biology, etc. Earth needs to be seen as a whole and not

separated from its subsystems.

What is a System

Can be any size group of interactive parts that form a complex whole.

Most natural systems are driven by sources of energy that move matter and/or energy from one place to another.

EX: Cooling system of a car. This is a closed system. Energy moves through the system and eventually out. No matter enters or leaves this system.

Most natural systems are open systems.

Both energy and matter flow into and out of the system.

Ex: A river system… the amount of water flowing changes all the time as well as the water temperature and even the ground temperature.

Earth as a System The Earth system is powered by two heat

sources…….1. the sun …this powers the atmosphere,

hydrosphere at the Earth’s surface.2. interior heat produced by radioactive materials

and frictionThe parts of the Earth system are linked so that a

change in one part can cause changes in another part or even the whole Earth.

Ex: A new volcanic island forms… What are the changes that can happen?

Human Effect

Burning fuels Getting rid of wastes Construction

The list is almost endless.

People and the Environment

The environment is everything that surrounds and influences and organism.

These influences can be both living and non-living factors…Name some?

All this comes under the heading of environmental science.

Environmental science is used for things that focus on relationships between people and the natural environment.

Resources

Include:

Water

Soil

Metallic and non-metallic minerals

Energy

Resources divided into 2 categories

Renewable – can replenish over a short period of time.

Ex: plants, animals and their products, water, wind for energy.

Nonrenewable – iron, aluminum, copper, other minerals, also fossil fuels.

The processes that form these are very slow perhaps millions of years.

Environmental problems May occur locally or regionally They include significant threats to the

environment which includes:Air pollutionSoil pollution and lossNatural hazardsAcid rainOzone deletionGlobal warming

What is Scientific Inquiry?

All science is based on two assumptions:

1. the natural world behaves in a consistent and predictable manner.

2. Through careful, systematic study, we can understand and explain the natural world’s behavior.

Developing New Scientific Knowledge Requires….. Gathering data through observation and

measurement. Forming a (n) hypothesis – this is a possible

explanation . Testing the hypothesis… If found to have merit

then…. Form a theory – which has been tested and widely

accepted by the scientific community and best explains certain observable facts.

This is the basis of the scientific method.