Science 7 Earth’s Crust...The crust is very thin under the ocean. It can range from being 5 km thick to over 60 km. 2. _____ The mantle is found underneath the crust. It is made

Science 7

Earth’s Crust Miss Tse

Name: __________________________________

Class: ___________________________________

Tse Science 7 Name: _______________________

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Unit 4: Topic 1

Minerals

Rock:

Minerals:

Minerals are quite rare since some of them are found in Earth’s ______________. This is

the thin outermost layer of Earth.

A mineral can be an ___________________, which a pure

substance or a ________________, which is two or more

elements combined.

There are multiple different ways to identify a mineral!

1. Mohs Hardness Scale:

A substance’s “scratch ability” can be used for mineral identification.

Science Friedrich Mohs developed a scale of ten minerals with a “hardness” value of 1 to 10.

Tse Science 7 Name: _______________________

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2. Crystals

Using crystal formation is a cool way to identify minerals.

Crystals:

Crystals occur naturally and have straight edges, flat sides, and regular angles.

There are six major crystal systems:

3. Lustre:

The surface of a mineral can reflect light in many different ways.

If a mineral shines like a polished metal surface, it is said to have a metallic lustre.

If a mineral has a duller shine, it has a _______________________________

lustre.

Tse Science 7 Name: _______________________

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4. Colors:

The problem with using color as an identification tool is that not all minerals are the

same color all the time. Color alone cannot identify a mineral.

5. Streak:

This occurs when a mineral is rubbed across a piece of unglazed porcelain tile.

When you examine the streak, you can distinguish different minerals.

Ex. Gold leaves a gold streak on the tile whereas pyrite (which is gold in color) leaves a

greenish-black or brown-black streak.

Minerals with a __________________________ hardness than the porcelain tile will not

leave a streak.

Some minerals that have a weak standing on the Mohs hardness scale will be crushed

when you try to test them on the porcelain plate.

6. Cleavage:

But not all minerals have cleavage.

Minerals that break with rough or jagged edges have __________________________.

Tse Science 7 Name: _______________________

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Unit 4: Topic 2

Rocks and the Rock Cycle

Rocks are grouped into three major families.

1. Igneous Rock:

Magma:

Lava:

Any rock heated at great depths can melt into magma. Under high pressure, the

magma can push away or dissolve the surrounding rock, making room for itself. This

causes magma to push up to the surface through cracks in the Earth’s crust.

There are two different types of igneous rocks. Geologists classify igneous rock based on

whether it was formed above or below Earth’s surface.

a) Intrusive Rock:

b) Extrusive Rock:

2. Sedimentary Rock

Sedimentary rock makes up about 75% of all rock that we can see on Earth’s

surface.

Sedimentary Rock is made from _____________________, which is loose material

such as rock, minerals, plant and animal remains that have been packed in layers and

cemented together.

Tse Science 7 Name: _______________________

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When you can see this arrangement, the

different layers in a piece of rock, it is

called

_________________________________.

This process of stratification normally

occurs in lakes and oceans where the

sediment settles over top of each other.

Each layer of sediment is squeezed together by the weight of other sediment and the

water on top of it.

This is called _______________________________.

Sometimes, minerals dissolve as the water soaks into

the rock. This forms natural cement that sticks the

larger pieces of sediment together. This process is

called __________________________.

3. Metamorphic Rock

Even though a rock has formed, it can still change its form!

Metamorphic Rock:

Parent rock:

Metamorphic rock can change so completely that it no longer looks like the parent rock.

But geologists can tell if rocks were related due to the common characteristics they

have.

Tse Science 7 Name: _______________________

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Rock Cycle

Rocks continue to change in an ongoing process called the rock cycle!

Sediment and Soil

How does soil form?

A layer of __________________ and _____________________ covers Earth. Plants

and animals add organic matter, such as leaves, twigs, dead insects and worms. The

organic matter creates spaces that can be filled with air or water.

All of these combine to form soil. Soil is a material that can ______________

plants.

Many factors affect soil formation such as climate, the type of rock, and the

amount of moisture. As well, small living creatures can affect the process of soil

formation.

Compost:

Compost mixes up with other decaying matter to form ______________, which is

very rich in nutrients and dark colored type of soil.

Humus helps keep water in the soil and is very good for plants.

Tse Science 7 Name: _______________________

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Fertile Soil:

Soil can actually take thousands of years to form! They range in thickness all over the

world. Some soil can be 60 meters thick and some can be just a few centimeters!

Scientists have exposed layers of soil with clear differences in appearance and

composition.

Soil profile:

Topsoil:

__________________________: The removal of soil materials dissolved in water

Tse Science 7 Name: _______________________

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Unit 4: Topic 3

Erosion

Erosion:

Do you remember the word sediments?

Sediments are formed due to ________________ and __________________________.

Weathering:

There are 3 different types of weathering.

1. Mechanical Weathering:

For example, when gravity causes rocks to shear off

from a mountain, the rocks roll down the slope and

become smoother and rounder.

_____________________________ can also cause mechanical weathering. In early spring, the

days are warm but at night, the temperatures become very cold. This time of year is known as the

freeze-thaw period.

During this period, the snow and ice melt during the warm daytime, which causes water

to seep into cracks of the rock. At night, the water freezes and expands which pushes the

cracks farther apart! After this happens over and over again, the rock breaks apart.

This entire process is called _________________________.

___________ and ________________ can wear away the surfaces of rock and carry the pieces to

another place. These pieces build up at this new location.

___________________________ is the part of the process responsible for “building up”.

Tse Science 7 Name: _______________________

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2. Chemical Weathering:

Chemical reactions can speed up the process of erosion. An example of chemical

weathering is _______________________.

Acid rain reacts very easily with limestone. The rain

causes the limestone to dissolve and wash away!

3. Biological Weathering:

For example, physical breakdown occurs when a plant root wedges

into a rock by forcing its way into a crack. As the root grows and

expands, so does the crack, and the rock is pushed apart until it

eventually crumbles and expands.

The Changing Surface of Earth

Glaciers are capable of changing the surface of the Earth. It

happens very slowly over many thousands of years. As glaciers pass over land, they erode it by

pushing sediments and scratching bedrock.

As well, wind can erode rock particles. When it blows across dry ground, wind picks up loose

sediment. These particles strike rock and wear it down.

This is called _______________________.

Water can also cause erosion. It can erode banks and fast moving water can carry away large

amounts of soil. Sometimes, water can break down rock and cause the coastline to lose several

meters every year.

Tse Science 7 Name: _______________________

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Unit 5: Topic 4

The Moving Crust

Did you know that Earth’s crust moves?

Scientists have been trying to solve the mystery of

the moving crust for thousands of years.

We are going to learn about the layers of the Earth.

1. __________________

This is the part of Earth that you walk on! It is home to

humans, animals, plants, and soil. It also has deep areas

where minerals are mined and oil and gas are formed.

The crust is very thin under the ocean.

It can range from being 5 km thick to over 60 km.

2. _____________________

The mantle is found underneath the crust. It is made of

rock material.

There are two mantles:

a)

This mantle is made out of solid material. This mantle combines with the

Earth’s crust to form the __________________________.

b)

This mantle is partially melted. Rock material in the mantle can flow

very slowly.

3. __________________________

It is made out of iron and nickel. The temperature in this section is over 5500° C. It is so

hot that the iron and nickel are in liquid state!

4. _____________________

This layer has such an intense pressure due to all the other layers of the Earth. This

pressure forces the inner core to form a solid ball. The temperature of the inner core is

over 6000° C.

Tse Science 7 Name: _______________________

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Continental Drift

Take a look at the map below. If the continents are fixed in place, why do they look like they

could fit together?

There was a scientist named Alfred Wegener

who wondered if the continents really did fit

together at one time.

He researched all over the world and found

that there were certain fossils of similar plants

and animals that could be found on different

continents.

Some of these fossils indicated that the

species could not swim so how did the

Lystrosaurus be in Africa AND South

America?

Some explanations are:

There was a bridge of land that connected the continents

that had existed and maybe it had disappeared over time

Trees might have fallen into the water and created a

bridge for the animals to walk over

Wegener studied his results and concluded that the continents had once been joined together.

Over millions of years, the continents had gradually moved to their present locations. He called

this ______________________________.

Advances in Technology

Due to the advancement of technology, a lot of information has been collected about Earth’s crust

from the sea floor by using sonar.

Sonar (Sound wave Technology):

This technology showed us that there were mountains on the sea floor.

Tse Science 7 Name: _______________________

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Plate Tectonics

The _____________________________ helps to explain how the crust moves!

The theory states that Earth’s crust is broken up into pieces called ____________. These

plates are always moving on Earth’s mantle.

If the plates are pushing together, they are called ______________________________.

If the plates are pulling apart, they are called ___________________________________.

A Canadian scientist named J. Tuzo Wilson made an important discovery however! He developed

the concept of a third kind of movement of the plates.

Instead of pushing or pulling apart, he said that the plates were sliding past each other.

Convection Currents:

Many scientists believe that convection currents are moving Earth’s plates.

When a plate touches another plate, this is called _______________________________.

Although these plates move very slowly, each movement affects another plate.

If converging plates are both continental, their edges may crumble and form mountains

If oceanic plate slides under a continental plate, melting occurs and volcanoes form

If two converging plates are oceanic, either plate might subduct, causing island arcs and

volcanoes

Subduction Zones:

Tse Science 7 Name: _______________________

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Unit 4: Topic 5

Earthquakes

Measuring Earthquakes

__________________________ use a special machine called a _____________________ to

measure earthquakes.

These seismographs must be attached to ___________________. This is solid rock that

lies beneath the soil and looser rocks. It has to be attached so that the machine can feel the

vibrations that result from an earthquake.

Inside the machine, a marking pen hangs over a rotating

drum so it can record the vibrations marked by the pen. When an

earthquake strikes, it shakes the bedrock, causing the pen to move

while the paper drum stays still.

Seismologists use a method of measurement called the Richter scale.

Richter Scale:

The scale starts as zero and goes as high as necessary. The amount of energy released

increases greatly as the numbers increase.

Tse Science 7 Name: _______________________

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Earthquake Waves

Seismic Waves:

Aftershocks:

These are actually smaller earthquakes that can cause damage to buildings and cause

them to collapse.

There are three kinds of earthquake waves:

1.

These waves travel the fastest and can pass through solids, liquids, and gases.

They cause a small vibration that would rattle plates on shelves. These vibrations warn

people in earthquake areas that an earthquake is about to happen.

2.

These waves travel more slowly than P waves.

They can only pass through solids, not liquids or gases.

3.

These are the slowest waves but their rolling

motion breaks up roads and buildings. They can cause

part of a building to move up while another part to go

down, causing a structure to collapse. These waves do

the most damage.

Tse Science 7 Name: _______________________

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Locating an Earthquake

We now know that P waves travel faster than S waves. Since this happens, it is possible to

determine the location of an earthquake by the interval between the P and S waves.

The farther apart the P and S waves are, the farther away the earthquake.

Scientists have two names for the source of an earthquake:

Focus:

Epicenter:

Types of Rock Movement in Earthquakes

1. Normal Faults

2. Reverse Faults

3. Strike-Slip or Transform Faults

Tse Science 7 Name: _______________________

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Preparing for Earthquakes

People who live in earthquake zones learn how to prepare for earthquakes.

In many homes, people attach their furniture to the walls. This prevents the walls from shifting

and falling over during an earthquake.

They store heavier items on shelves that are nearer the floor so heavy items do not fall off the

shelves and onto a person during the quakes.

Engineers try to construct buildings and roads to be earthquake resistant. Rigid structures of

bricks or solid concrete break during an earthquake because they have little flexibility.

Other Effects of Earthquakes

Some earthquakes happen under the sea. The water displaced by an earthquake can become huge

waves called ____________________. Tsunamis can travel across oceans and cause great

damage when they break on the shore.

In mountains, earthquakes can trigger avalanches or rock slides.

Tse Science 7 Name: _______________________

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Unit 4: Topic 6

Volcanoes

Volcano:

These openings are called __________________.

When a volcano is not active, it is called a _________________ volcano. Scientists study these

dormant volcanoes to predict when they will erupt so that the people living near them can avoid

injury or death.

Volcanoes can be formed when rock surfaces beneath Earth’s crust push against one another. The

part of the crust that is pushed downward reaches very hot areas where it melts and becomes

magma.

After a while, there is so much magma, it is forced up through the opening and erupts!

Ring of Fire:

There are many interesting volcano videos on YouTube!

Tse Science 7 Name: _______________________

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Unit 4: Topic 7

Mountains

Mountain building takes many years. Each mountain range has a distinctive and fascinating

geological history due to plate tectonics.

Most mountains are large areas that have been

uplifted due to the movement or heating of plates.

The plates can converge, diverge or slide past

each other. The movement along these boundaries

can create great heat and pressure. The pressure

can cause the rocks to fold and fault, creating

mountains.

Sedimentary rocks that are placed under slow

gradual pressure can fold or break. Geologists

explain that rocks can fold if they are hot enough

to act like bendable plastic. The soft rock may

bend into curves.

Some of these sedimentary rocks can be changed to metamorphic rock due to the ____________

and ______________.

Anticline:

____________________: the bottom of the fold

Ages of Mountains

Young mountains: Old mountains:

Tse Science 7 Name: _______________________

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Unit 4: Topic 8

Fossils

Fossils are able to provide clues about when life began

and when plants and animals first lived on land.

Fossils tell us when certain organisms, such as

dinosaurs, flourished and disappeared.

Fossils can also tell us how that organism lived and

behaved.

Fossils:

There are different types of fossils:

1. Petrified

2. Carbonaceous Film

Original remains:

Trace fossils:

These can be evidence of animal activity.

Tse Science 7 Name: _______________________

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Fossil Mold and Cast Formation

When an organism falls into sediment, the sediment

turns into rock over a long period of time. Water and

air pass through pores in the rock, which reaches the

organism. Its hard parts dissolve which leaves a

cavity in the rock.

This is called a _______________________.

Other sediments or minerals may fill this hole, which causes the rocks to harden and produce a

______________ of the original subject.

Tse Science 7 Name: _______________________

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Unit 4: Topic 9

Geologic Time

Geologists use this principle to infer the relative ages of

different layers of rock.

Principle of Superposition:

Another term for these sedimentary layers of rock is

_________________.

Geologists also used _______________________ to find the order in which events occur. They

determine the relative age of rocks by examining their position in the strata. If a crack or a fault

runs through a layer, it must have happened after the layer was in place, so the rock is older than

the fault.

Some fossils can be used to determine the age of the layer of rock in which they are found.

Index Fossil:

To determine the ages of rocks, geologists examine the amount of elements in a rock. Over billion

of years, some elements can change into other.

For example, over 4.5 billion years, half of the uranium in a rock will turn into lead.

Half-life:

Diagram example:

Tse Science 7 Name: _______________________

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Scientists also use a technique called ________________________ to find out when recent

events in Earth’s history occurred.

This uses carbon-14, which is a rare form of carbon.

Definition:

This method is used to find the age of fossils, bones, and wood.

Geologic Time Scale

A geologic time scale is a division of Earth’s history into smaller units based on the appearances

of different life forms.

It stars 4.5 billion years ago when Earth was formed.

__________ are divided into __________ which are then divided into _____________.

Precambrian is what the first 4 billion years of Earth is called.

The supercontinent, ___________________, was formed during this time. Rodinia spilt

apart 750 million years ago which formed the ocean basins.

The next three eras are Paleozoic Era (ancient life), Mesozoic Era (middle life), and Cenozoic

Era (recent life).

The second supercontinent to form was ________________. This came together during

the Paleozoic Era and broke up during the Mesozoic Era.

Tse Science 7 Name: _______________________

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Tse Science 7 Name: _______________________

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Unit 4: Topic 10

Fossil Fuels

The source of most fuels used is ____________________. This is a naturally occurring mixture

of hydrocarbons such as bitumen, coal, oil and gas.

Petroleum is often found in sedimentary rock basins. These basins were formed from the

sediments of tiny plants and animals deposited in the mud. The basins were under heat and

pressure for millions of years.

During this time, the soft parts of plants and animals were transformed into solid, liquid,

or gas hydrocarbons called __________________.

How do earth scientists know where to find oil and gas?

They study surface rocks and samples from deep within the ground to identify traps

where oil and gas have accumulated within rock formations.

Bitumen:

Some bitumen deposits are found near the surface and can be mined. Hot water is used to

separate the bitumen from the sand at the processing plant.

Tse Science 7 Name: _______________________

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