Earth’s changing surface

Earth’s changing surface Earth’s changing surface Book “G” chapter 1 page 4

Section 1 page 6 exploring Earths surface

Section 1 page 6 exploring Earths surface

• Topography: the shape of the land determined by elevation, relief, and landforms. – Examples: what is the topography where our

school sits? what is it where your house is? Is it all the same?

Elevation Elevation

• Elevation: The height above sea level of a point on earth. – Sea level: is where we start at zero. Then we

go up from there. – Why sea level ? What makes sea level so

universal – What measurements do we use when talking

about elevation?• Feet

Relief Relief

• Relief :the difference in elevation between the highest and lowest parts of an area.– Low relief = low rolling hill measured agents

flat plains.– High relief = rocky mountains measured

agents valleys.

LandformsLandforms

• Landforms : a feature of topography formed by the processes that shape Earths surface.– Mountains– plateaus– Plains– Oceans, rivers

Mountains Mountains

• Mountains : a landform with high elevation and high relief.– Mountain range : a group of mountains

closely related in shape, structure, and age.• Rocky mountains• Sierra Nevada mountains• Himalaya mountains • Wasatch mountains

Plains Plains

• Plains : is a landform that is made up of nearly flat or gently rolling land with low relief. – Coastal plains

• Along the Eastern and Western coastlines of the U.S.

– Great plains• In the middle of the U.S. from Oklahoma and

Texas to Canada.

Plateaus Plateaus

• Plateaus : a landform that has high elevation and more or less level surface.– These are rarely flat and smooth, there are

usually rivers and streams that cut into the surface.

Earth Models Earth Models

• Earth models are used to show the earth in a scale in the forms of maps and globes.

Maps Maps

• Map: a flat model of all or part of the Earths surface as seen from above.– Scale: relates distance on a map to a distance

on the Earths surface. Scale is often given as a ratio.

• Example: one unit on a map could equal 25,000 units on the ground. So one centimeter on the map would equal 0.25 of a km on the ground.

Key’s & legends Key’s & legends

• Map makers use keys and legends to help the reader of the map understand the symbols used on the map and what they mean.

• Now lets see what it is I’m talking about.

Globes Globes

• Globes : is a sphere the represents the Earths entire surface. – The advantage of a globe is that it can

accurately represent the Earth in relative scale because its round.

– A map is flat so it looses some of the proportions.

Measuring in Degrees Measuring in Degrees

• We are not talking about tempature. – The Earth is dived into equal degrees.

• How many degrees is it divided into?– 360

• To locate positions on the Earth’s surface scientists use units called degrees. These units are quiet large to make precise measurements.

– So we came up with smaller units does anybody know what they are.

» Degrees are divide up into minutes and seconds.

Divided in half?Divided in half?

• Now that we have the Earth divided into equal segments what's left?– There are two way the earth is divided in half

who knows what they are?• The Equator

– Is an imaginary line that circles Earth half way between the North and South poles.

• Prime Meridian– Is an imaginary line that makes a half circle from the

North pole to the South pole and passes through Greenwich ,England

There’s MoreThere’s More

• Now that we have 360 degrees that equally divides that Earth, minutes and seconds that give us a precise way to locate something on a large globe. An equator and prim meridian that separated the North, South, East, West from Each other. What else could we possibly need?

From top to bottom From top to bottom

• Latitude : The distance in degrees North or South of the Equator.– Were do you start?

• The equator and its degree is 0

– Between the equator and each pole are 90 evenly spaced degrees. Each one is equal to 111 km

From side to side From side to side

• Longitude : the distance in degrees East or West of the Prime meridian.– Were do we start?

• prime meridian– There are 360 lines

that run North and South and meet at the poles. Each degree represents about 111 km at the equator.

Topographic maps Topographic maps

• A topographic map: is a map showing the surface features of an area. – Topographic maps use symbols to portray the

land as if you were looking down at it from above. Map makes use contour lines to represent elevation, relief , and slope on the map.

• the unit of measurement are feet in the U.S. other places use meters.

– Are they useful?» Vary useful for hunting, hiking, building, mining, ect.

Chapter 2 weathering and soil formation.

Chapter 2 weathering and soil formation.

There are two typesThere are two types

• What are the two types of weathering?– Mechanical weathering: Is when rock is

physical broken into smaller pieces.• This type of weathering doesn’t change the

composition of the rock. Its like hitting a rock with a hammer, the rock is smaller but its still the same as it was before.

– Examples of this would be rocks in plies below an outcrop, smaller pieces have been broken off.

Types of weathering continuedTypes of weathering continued

• The other type is?– Chemical weathering: this brakes down rock

through chemical changes. • These process include the actions of water,

oxygen, carbon dioxide, living organisms, and acid rain.

– Mechanical and chemical weather usually work together. Chemical weathering produced holes in the rock that makes it easier to break into small pieces which creates more surface area which allows chemical weathering to act faster.

WICH OF THESE IS THE MOST IMPORTANT?

WICH OF THESE IS THE MOST IMPORTANT?

• There are five ways that chemical weathering can occur. But which one is the most IMPORTANT?– Water : water is by far the most important.

Water dissolves rock and that allows the “stuff” to mix with the water making a solution.

– The others play important parts but water is the most important .

The finished productThe finished product

• So what do we have after chemical weathering?– For example: granite contains many different

elements and minerals some of these are feldspar, quarts and mica.

• As a result of chemical weathering feldspar changes into clay minerals. That’s why our valley here has so much clay because our mountain’s are granite.

• TIME FOR THE FIZZING ANTACID EXPERIMENT

Erosion Erosion

• Now that the rocks are broken up and made smaller by weathering how do we move them?– Erosion: the process by which water, ice,

wind, or gravity moves weathered rock and soil.

• This is how the rocks are moved from the mountain down to the valley

Rate of weathering Rate of weathering

• What is rate?– Is the time it takes or the speed at which

something occurs.

• What are the two things that can effect rate?– Type of rock

• If the rock is vary hard or vary soft this will effect the rate

– Climate• If the climate is wet or dry this will effect the rate.

Section 2 how soils form.Section 2 how soils form.

• First we need to know what soil is. – Soil : is the loose weathered material on

Earths surface in which plants can grow. • This is what rocks end up as after weathering and

erosion. Soil is a mixture of rock particles, minerals, decayed organic material, water, and air.

– Humus is a very important part of a soil it is a dark colored substance that forms as plant and animal remains decay. This is what makes soil fertil.

• There are two part to the soil level top soil and sub soil.

Soil conservation Soil conservation

• What is soil conservation?– The ability to keep soil from being lost due to

erosion forces.• Why is this important?

– Because everything on land depends directly or indirectly on soil.

» Plants

» Animals that eat plants.

» Animals that eat animal that eat plants.

– Ways to keep soil include reducing erosion by increasing plants, diverting rivers, proper land management techniques

Chapter 3 Erosion and DepositionChapter 3 Erosion and Deposition

• We know what erosion is, but what is deposition?– Deposition : Is the process in which sediment

id deposited or laid down in a new location.– Sediment : may consist of pieces of rock or

soil or the remains of plants and animals.• What force is the major player in this process?

– Gravity » Gravity causes the movement of sediment and

causes it to be laid down, it can also cause mass movement of sediment.

Mass movement Mass movement

There are different types of mass movement and they include landslides, mudflows, slumps, and creeps.

which of these do you think is the most destructive?

landslides.

Landslides Landslides

• Landslide: occurs when rock and soil slide quickly down a steep slope.– Why do landslides happen?

• There are many reasons why, Earth quakes, cutting into a hill. When vegetation is removed by fire or grazing.

Landslide picLandslide pic

MUDFLOWMUDFLOW

• Mudflow : is the rapid downhill movement of water, rocks, and soil.– Mudflow happen all of the time Earth quakes

can set them off, as well as a light rain. – It all depends on how saturated the soil is.

Mudflow picsMudflow pics

Slumps Slumps

• Slump: a mass of rock and soil suddenly slips down a slope.– Unlike a landslide a slump is when material

suddenly moves in one large mass.

Slump picSlump pic

CreepCreep

• Creep : is a very slow downhill movement of rock and soil. It can even occur on gentle slopes. – what do thing causes soil to creep?

• Usally is happens from freezing and thawing in water of cracked layers of rock beneath the soil.

– It happens so slow that you cont really see it happen while you are watching it. Like a flower opening, but over time you can see the effect , on telephone poles, fence posts, and grave stones.

Water Erosion Water Erosion

• Moving water is the major agent of erosion that has shaped the Earths surface since water has been on land.– Water erosion includes spring runoff, rivers,

streams, lakes, rain, snow, Ice,• All of this water, has to go somewhere. What do

we call it?– Flood plain: the flat\ wide area of land along a river.

» All of the water on earth that comes from the different types of precipitation end up in rivers streams, and then in some form of a stable body of water. Oceans, lakes and reservoirs.

Flood plain Flood plain

Water Erosion continued Water Erosion continued

• The water carries sediments in it and deposits these sediments in the flood plain, and deltas of the body of water.– How dose this impact us?

• Who knows what they want to do to lake Powell?– They want to drain it because they say its filling up with

sediment form the Colorado river.

• Look at the picture on pages 78-79 in book “G” of your science book.

Deltas Deltas

Ground water Erosion Ground water Erosion

• When rain and snow fall not all of evaporates or runs off into the rivers and streams. A lot of it goes directly into the ground. – Ground water: is water the fills the cracks and

spaces in underground soil and rock layers. • What effect can this have?

– When water enters the ground it combines with CO2 to form carbonic acid. This acid can dissolve limestone, which over long period of time can result in underground caves.

» It can also have other effects, when there is a drought , the soil will absorb water instead of allowing it to go into the lakes and rivers.

Glaciers Glaciers

• Our continent has had a lot of influence from glaciers. Glaciers created the great lakes. They smoothed out the great plains, and here in our stat they carved out many of our canyons. All of the large granite boulders that you see at the entrance of the canyons were moved there by glaciers– Glacier : is ant large mass of ice that moves

slowly over land.

Two types of glaciresTwo types of glacires

• Continental glaciers : is a glacier that covers much of a continent or large island.

• Valley glaciers: is a long, narrow glacier that forms when snow and ice build up high in a mountain valley. – How do glaciers form?

• High in mountain valleys temperatures seldom rise above freezing. Snow build up year after year, and the weight compact everything at the bottom into ice. When its big enough gravity pulls it downhill.

– Glaciers can only form in an area where more snow falls than melts.

Waves Waves

• How are waves formed?– Wind ; some of the energy from wind is

transferred to the water creating waves. • Waves are the major force of erosion along the

coastline. Waves shape the coast through the constant pounding of water; breaking down rock and transporting sand and other sediment.

– Where do beaches come from.• As waves reach the shore, they drop the sediment

they carry forming a beach. – Beach : is an area of wave- washed sediment along the

coast.

Wind Wind

• How does wind cause erosion?– Wind causes erosion by deflation and

abrasion. • The main way wind causes erosion is by deflation.

– Deflation : wind erosion that removed surface material

• The other way is abrasion– Abrasion :the grinding away of rock by other rock

particles carried in water, ice, or wind.» Wind can carry sediments across the oceans. And

create an entirely new place in the desert in the form of sand dunes.