Earth Science –Bennett HS—Q4 –Notebook

The following notes should be entered into your notebooks (a spiral notebook or loose leaf paper in a 3-ring binder), in chronological order and will be collected and graded during the last week of the marking period.. Blank lines and any information that appears in brackets “[xxxx]” is information that should have been entered by each student and will vary for each student.

--Ms. Milligan

4/18/2005

Weathering, Erosion & Deposition (WED)

Introduction

· weathering, erosion, and deposition are a main force behind landscape types

· But they are not the only reason for a plain, plateau, and mountain region to form

o Other factors such as glaciation and tectonic activity lead to landscape building

§ In New York State, glaciation is one of the main causes of many types of landscape regions

o the water cycle or hydrologic cycle (see graphic below) is the driving force behind WED (weathering, erosion, and deposition)

o winds also help form the surface landscape

o But without gravity and the sun this whole process would not occur

Water Cycle Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

The water cycle process looks like this:

Evaporation Þ condensation Þ precipitation Þ infiltration Þ run-off

Without this process, weathering, erosion, and deposition would have a difficult time occurring on Earth.   

Weathering

-- chemical and physical processes that change the characteristics of rocks on the Earth’s surface.

o for weathering to occur, the rock sample must change and rock needs to be exposed to water and air

o Human processes such as pollution, (like acid rain) along with the acts of other living organisms, can cause chemical weathering to occur at faster rates. 

Weathering Process
The weathering process occurs when rocks are exposed to the hydrosphere (water) and atmosphere (air).

· These agents can change the physical and chemical characteristics of rocks.

· As rocks are broken down (weathered), they can be classified as different types of sediments, which are:

o boulders, cobbles, pebbles, sand, silt, clay, and colloids.

Fill in the following table using page 6 of the Earth Science Reference Tables, the graph that shows particle sizes:

Name of Particle

Minimum Diameter (cm)

Maximum Diameter (cm)

4/20/2005

Physical Weathering
-- when rocks are broken in to smaller pieces without changing the chemical composition of the rock.

· Think of a physical change (e.g., ripping a piece of paper) -- will change size, but all other characteristics will remain the same

· Types of physical weathering:

o Frost action/ice wedging -- breakup of rock caused by the freezing and thawing (contracting and expansion) of water. A very similar process occurs on roads, which causes potholes.

Frost Wedging Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

o Abrasion --physical wearing down of rocks as they rub or bounce against each other--most common in windy areas, under glaciers, or in stream channels.

o Exfoliation --peeling away of large sheets of loosened materials at the surface of a rock. Common in shale, slate, and mica.

4/21/2005

Chemical Weathering
--when a rock is broken down by chemical action resulting in a change in the composition of a rock.

· Such as the change a piece of paper would go through after being burned.

· Main agents of chemical weathering are oxygen, rainwater, carbon dioxide, and acids produced by decaying plants and animals that leads to the formation of soil.

· There are a few types of chemical weathering such as:

o Oxidation -- when oxygen interacts chemically with minerals.

o Hydration -- when water interacts chemically with minerals.

o Carbonation -- when carbon dioxide interacts chemically with minerals.

What climatic conditions normally produce the greatest amount of chemical weathering and why?

_______________________________________________

_______________________________________________

_______________________________________________

_______________________________________________

4/25/2005

Type Type

Changes

Examples

Weathering Rates

--depend on 3 different factors:

o Particle size/surface area exposed to the surface

--smaller particle sizes weathered faster

--larger exposed surface area weathered faster

o Mineral composition

o Climate –wet & warm climates increase weathering rates

Soil Formation

· One of the major products of weathering is soil

· Soil -- combination of particles of rocks, minerals, and organic matter

· Soil contains the necessary nutrients to support plant and animal life

· As a result of the weathering processes and biologic activity, soil horizons (layers) form

The below diagram is a mature soil profile common to New York State:

Soil Profile Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

· Horizon O -- organic material on the upper most part of the profile (this layer is usually very thin)

· Horizon A -- commonly known as topsoil

o would probably include organic material (humus), such as fallen leaves, twigs, decaying plant and animal remains.

o helps prevent erosion, holds moisture, and decays to form a very rich soil known as humus.

· Horizon B -- the subsoil.

o usually will contain a fair amount of clay and iron oxides

· Horizon C --mostly of weatherized big rocks known as Parent material (the rock that the soil formed from)

· Horizon D -- is not shown in this illustration, usually contains solid bedrock.

4/26/2005

FACTORS THAT AFFECT THE WEATHERING RATE

4/27/2005

Erosion

Erosion refers to the transportation of rock, soil, and mineral particles.

· moving element.

· main driving force is gravity.

· Without gravity wind, running water, glaciers, waves, and rain would not occur.

Factors Affecting Transportation of Sediments

· Running water

· Factors affecting the movement of sediments in a stream:

o Gradient (slope)

o Discharge

o channel shape

· sediments rounded due to the grinding action, a process called abrasion

· The watershed of a stream is the area drained by a stream and its tributaries (smaller feeder streams).

· The average velocity (speed) of a stream depends on its slope and discharge, which in turn can explain the carrying power of a stream.

4/28/2005

Fill in the following table using page 6 of the Earth Science Reference Tables, the graph that shows the relationship between stream velocity and particle size transport:

Stream Velocity (cm/sec)	Maximum Diameter (cm) transported	Name of largest Particle moved
25
75
100
250
400
600

· Meanders (see diagram below)

o Deposits-velocity is lowest along the inner banks

o Along a straight channel segment, fastest in mid-channel, near the surface.

o Erosion-around a bend, the zone of high velocity swings to the outside of the channel.

o another landform -- an oxbow lake -- can develop-- forming an independent loop that will become a lake

Oxbow Lake Formation Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

Valleys Eroded by Streams and Glaciers

· Valleys that have been eroded:

o by streams are v-shaped

o by glaciers are u-shaped

Effect of Humans on Erosion
Humans add greatly to the natural processes of land erosion through activities, such as:

· highway and construction,

· destruction of forests (clear-cutting),

· set forest fires,

· poor landfill projects, etc…

· Today, human activities contribute more than ever to the erosion on the Earth’s surface

4/29/2005

Fill in the following graphic organizer with the information for your notes about erosion:

EROSION

AGENTS

OF

EROSION

Fill in the following Venn Diagram with the elements of Weathering an Erosion from your notes:

WEATHERING EROSION

5/4/2005

Deposition

-- Rock particles are deposited somewhere else --the final step in the erosional-depositional system.

· agents of erosion become agents of deposition

· Final deposition of particles (sediments) usually occurs at the mouth of a stream--a process called horizontal sorting takes place:

o The sediments that were once carried down the stream are arranged from largest to smallest.

Stream Horizontal Sorting Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

5/5/2005

Factors Affecting Deposition
The major factors that affect the rate of deposition are:

· particle size, shape, density, and the velocity of the transporting stream:

o Size: smaller particles settle more slowly than the larger particles, due to gravity. The smaller particles tend to stay in suspension for longer periods of time. This form of deposition is called graded bedding or vertical sorting. The diagram below shows graded bedding.

Graded Bedding Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

· Shape: A round sediment compared to a flat (skipping stone) sediment of equal size will settle faster in a body of water. The graphic below shows the relationship.

Rate of Settling Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

· Density: If particles are the same size but have different densities the higher density particle will settle faster

· Velocity:

o If the stream slows down during a drought period, the carrying power will decrease and the particle sizes carried and deposited will also decrease.

o If a stream is flowing faster due to flood conditions, then the carrying power of the stream will increase and the sizes of particles deposited will increase as well.

Glacial Deposition
Glacial ice deposits --very different from stream (water) deposits.

· Glacial deposits of gravel, boulders, and sand are unsorted with no layer as in graded bedding.

· Till which is the accumulation of sediments carried by a glacier is very sharp like broken glass.

The diagram below shows the unsorted nature of glacial deposits:

Glacial Deposits Diagram

[click here to see the diagram and copy it (including the labels) into your notes]

5/16/2005

WATER

“Water – a clear, pure crisp drink for any time of day or night. Choicest combination of hydrogen and oxygen atoms, aged billions of years and recycled through natural processes. From the coldest glaciers to the depths of the oceans, water has been the elixir of life since life began. First choice of discrimination plants, animals, and other living things.”

5/16/2005

Electromagnetic Spectrum & Solar Energy

· All matter at temperatures above absolute zero (-273°C) radiates à gives off energy

· Our Sun produces energy in all frequencies of the Electromagnetic (EM) Spectrum

· The energy travels to our Earth in the form of waves

Fill in the following table using pg. 14 ESRT

Name of EM wave

Wavelength range (cm)

· Visible light à smallest part of the EM spectrum, but the greatest intensity of these are received by Earth

· Ultraviolet & Infrared à most energy received by Sun

· The shorter the wavelength, the greater the risk to human health

Name the two types of EM waves that have the shortest wavelength:

_____________ & _________________

5/19/2005

In Insolation

· Incoming Solar Radiation à can be absorbed, reflected, & re-radiated

· The sun heats the Earth unevenly through out the day

· The angle of incidence of the Sun changes (Sun at different angles above the horizon)

· At lower angles, the surface area of contact (insolation) is greater—spreading out that energy à less intense

Sun’s Angle of Incidence

[click here to see the diagram and copy it (including the labels) into your notes]

At which angle is the radiation the most intense? ______

What time of day are the Sun’s rays at a 90° angle to the surface of the Earth? ________

· Smooth & light colored surfaces are good reflectors, poor absorbers of radiation (examples: snow, water)

· Rough (more surface area) & dark surfaces are good absorbers, poor reflectors of radiation

(examples: dirt, dark blue cotton shirt)

5/23/2005

In Specific Heat

· Specific Heat à the amount of energy required to raise the temperature 1 degree Celsius of a material with a mass of 1 gram

· A material’s Specific Heat determines if it is a good absorber of energy (radiation)

· Each material has a unique Specific Heat

· The lower the Specific Heat, the faster that material heats up and cools down

· See pg. 1 of ESRT—answer these questions below:

What two materials heat up the fastest and cool down the fastest? ______________ & ___________________

What two materials heat up the slowest and cool down the slowest? ______________ & ___________________

What area would most likely have the most temperature changes near and around it, land or water? _____________

Is the weather over the water or land less predictable? _______________

Why? _________________________________________

______________________________________________

_____________________________________________________________________________

5/24/2005

How many words about weather do you know?

List the words below…..

5/26/2005

In Weather

· Weather àShort-term condition of the atmosphere caused by unequal heating of the Earth’s surface

· The two main factors that affect weather are the angle of Insolation and the surface conditions

· Morning à angle of Insolation is low, low heating

· Noon à angle of Insolation (90°) is greatest, greatest heating

· Afternoon à cools down again, since angle is decreasing again

· Land heats up faster than water. Why?_________________________________________________________________________________

· Atmospheric variables that can be measured and used by scientists to predict weather:

1. air pressure

2. precipitation

3. air temperature

4. humidity

5. dew point temperature

6. wind speed

7. wind direction

5/26/2005

BARAMETRIC PRESSURE
What I Know	Think I Know	Want to Know
1. 2. 3.	1. 2. 3.	1. 2. 3.

5/31/2005

List how many words you know to describe humidity:

6/1/2005

In Cloud Formation & Precipitation (Rain)

· Clouds form when:

à warm, moist air rises

à cools to the dewpoint temperature

à condense on condensation nuclei

(particles of dust, dirt, pollution)

· Precipitation (Rain) occurs when:

à cloud droplets increase to a diameter of about 2mm

à they begin to fall as precipitation

à two natural processes that cause

the droplets to get bigger:

1. coalescence—drops combine with smaller drops

2. supercooling—cooled below freezing, condensation, sublimation point without changing state

6/6/2005

Wind

· Wind is large horizontal movement of air

· Cause of wind is: differences in air temperature, which causes pressure differences

· Winds move from high pressure to low pressure

· Winds blow around high pressure systems:

Outward, clockwise (HOC)

· Winds blow around low pressure systems:

inward, counter-clockwise (LICC)

Winds in the Northern Hemisphere

[click here to see the diagram and copy it (including the labels) into your notes]

6/7/2005

Weather Station Models

Sample Weather Station Model

[click here to see the diagram and copy it (including the labels) into your notes]

· Pressure is reported to the nearest tenth of a millibar.

· Add either a 10 or 9 in front based on which would bring the value closer to 1000.

· The pressure here is 999.8 millibars (mb).

· If < 500, put decimal at tenths place and add a “10” in front

· If > 500, put decimal at tenths place and add a “9” in front

Examples:

Model pressure = 196 à 1019.6 mb

Model pressure = 51 à 1005.1 mb

Model pressure = 696 à 969.6 mb

Adapted from: Regents Exam Prep Center http://regentsprep.org/Regents/earthsci/earthsci.cfm

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