Chapter 5 Study Guide for Test on Thursday, January 5th!!!!!

Chapter 5 Study Guide

Volcanoes

Where do volcanic belts form?

Answer:  Volcanic belts form along the boundaries of Earth’s plates.

What is the difference between magma and lava?

Answer:  Magma is a molten mixture of rock-forming substances, gases, and water from the mantle.  When magma reaches the SURFACE of the Earth, it is called lava. 

True or False---

After magma and lava cool, they form solid rock.     TRUE!!!!

What is the Ring of Fire?

Answer:  It is one major belt of volcanoes that includes the many volcanoes that rim the Pacific Ocean including those along the coasts of North and South America and those in Japan and the Phillipines.

What is a string of islands created by volcanoes formed from converging boundaries?

Answer:  an island arc

What is another way that volcanoes can form other than along plate boundaries?

Answer:  A volcano forms above a HOT SPOT (an area where material from deep within Earth’s mantle rises through the crust and melts to form magma). 

List and explain the parts of a volcano (a system of passageways through which magma moves).

1.      Magma chamber-All volcanoes have a pocket of magma beneath the surface.  Beneath a volcano, magma collects in a magma chamber.  During an eruption, the magma forces its way through one or more cracks in Earth’s crust.

2.      Pipe-Magma moves through a pipe, a long tube that extends from Earth’s crust up through the top of the volcano, connecting the magma chamber to Earth’s surface.

3.      Vent-Molten rock and gas leave the volcano through an opening called a vent.  Some volcanoes have a single central vent at the top.  But volcanoes often have vents on the sides also.

4.      Lava flow-a lava flow is the spread of lava as it pours out of a vent.

5.      Crater-a crater is a bowl-shaped area that may form at the top of a volcano around the central vent.

True or False---

When a volcano erupts, the force of the expanding gases pushes magma from the magma chamber through the pipe until it flows or explodes out of the vent.  TRUE!!!!

What is silica?

Answer:  Silica is a material found in magma that forms from the elements oxygen and silicon.

Name two types of volcanic eruptions:

1.      Quiet eruptions-a volcano erupts quietly if its magma is hot or low in silica.  Hot, low silica is thin and runny and flows easily.  The gases in the magma bubble out gently.  Low-silica lava oozes quietly from the vent and can flow for many kilometers.

Quiet eruptions can produce different types of lava:

Pahoehoe (pah HOH ee hoh ee) forms from fast-moving, hot lava that is thin and runny.  The surface of pahoehoe looks like a solid mass of ropelike coils.

Aa (AH ah) forms from lava that is cooler and thicker.  The lava that aa forms from is also slower-moving.  It has a rough surface consisting of jagged lava chunks.

Example of a quiet eruption: the Hawaiian Islands

2.      Explosive eruptions-a volcano erupts explosively if its magma is high in silica.  High-silica magma is thick and sticky.  It can build up in the volcano’s pipe, plugging it like a cork in a bottle.  Dissolved gases cannot escape from the thick magma.  The trapped gases build up pressure until they explode.  Lava is powerfully thrown into the air where it breaks into fragments of different sizes.  The smallest pieces are volcanic ash, and the larger pieces, called bombs, may range from the size of a golf ball to the size of a car.

Example of an explosive eruption:  Mount St. Helens in Washington State (1980)

What is a pyroclastic flow?

Answer:  It is a mixture of hot gases, ash, cinders, and bombs that flow down the sides of a volcano when it erupts explosively.  Landslides of mud, melted snow, and rock can also form from an explosive eruption.

What are the stages of volcanic activity?

Answer: 

1-      Dormant—a sleeping volcano that scientists expect to awaken in the future and become active.

2-      Extinct---a dead volcano that is unlikely to ever erupt again.

3-      Active---a live volcano is one that is erupting, or has shown signs that it may erupt, in the near future.

What is a caldera?

Answer:  A caldera is a huge hole left by the collapse of volcanoes.

What landforms do VOLCANIC ERUPTIONS create?

Answer:

1-      Calderas—large holes at the top of volcanoes formed when the roof of a volcano’s magma chamber collapses.

2-      Shield Volcanoes---wide, gently sloping mountains made of layers of lava and formed by quiet eruptions.

Example of a shield volcano:  Mauna Loa in Hawaii

3-      Cinder Cone Volcanoes---steep, cone-shaped hills or small mountains made of volcanic ash, cinders, and bombs piled up around a volcano’s opening.

Example of a cinder cone volcano:  Paricutín in Mexico

4.      Composite Volcanoes---tall, cone-shaped mountains in which layers of lava alternate with layers of ash and other volcanic materials.

Example of a composite volcano:  Mount Fuji in Japan & Mount St. Helens in Washington State

5.      Lava Plateaus---thin, runny lava flows out of several long cracks in an area and travels before cooling and solidifying.  After millions of years, repeated floods of lava can form high, level plateaus.  These are called lava plateaus.

Example of a lava plateau:  Columbia Plateau—covers parts of Washington State, Oregon, and Idaho

What landforms does MAGMA create?

*Sometimes magma cools and hardens into rock before reaching the surface.  Over time, forces such as flowing water, ice, or wind may strip away the layers above the hardened magma and expose it.

1.      Volcanic Necks---form when magma hardens in a volcano’s pipe and the surrounding rock later wears away.

2.      Dikes---form when magma forces itself across rock layers and hardens.

3.      Sills---form when magma squeezes between horizontal rock layers and harden.

4.      Dome Mountains---form when uplift pushes a large body of hardened magma toward the surface. The hardened magma forces the layers of rock to bend upward into a dome shape.

5.      Batholiths---masses of rock formed when a large body of magma cools inside the crust.

Chapter 4 Study Guide Test on Tuesday, December 7th!!!!

Study Guide

Chapter 4 Test

Know all of your vocabulary!  Take your Vocab Folder home to study.

What is stress?

Answer:  Stress is a force that acts on rock to change its shape or volume.

What works over millions of years to change the shape and volume of rock?

·         Tension-the stress force that pulls on the crust and thins rock in the middle.

·         Compression-the stress force that squeezes rock until it folds or breaks.

·         Shearing-the stress that pushes a mass of rock in two opposite directions.

What is a fault?

Answer:  A fault is a break in the rock of the crust where rock surfaces slip past each other.

How do faults form?

Answer:  When enough stress builds up in rock, the rock breaks, creating a fault.

Name and describe the 3 main types of faults.

o   Normal Fault-the fault cuts through rock at an angle, so one block of rock sits over the fault, while the other block lies under the fault.

*The hanging wall moves down!

o   Reverse Fault-this fault has the same structure as a normal fault, but the blocks move in the reverse direction.

*The hanging wall moves up!

o   Strike-Slip Fault-the rocks on either side of the fault slip    past each other sideways, with little up or down motion. (transform boundary)

How does plate movement create new landforms?

o   Anticlines-a fold in a rock that bends upward into an arch.

o   Syncline-a fold in rock that bends downward to form a V-shape.

o   Folded mountains-the collision of two plates can cause compression and folding of the crust over a wide area.  Folding produced some of the world’s largest mountain ranges—The Himalayas in Asia  AND The Alps in Europe.

o   Fault-block mountains-two plates move away from each other and tension forces create many normal faults.  As the hanging wall of each normal fault slips downward, the block in between now stands above the surrounding valleys, forming a fault-block mountain.

o   Plateau-the forces that raise mountains can also uplift, or raise, plateaus (large areas of the land elevated high above sea level).

What causes earthquakes?

Answer:  The forces of plate movement produce stress in Earth’s crust, adding energy to rock and forming faults. Eventually the stress increases along a fault until the rock slips or breaks, causing an earthquake.

What are seismic waves?

Answer:  Seismic waves are vibrations that are similar to sound waves.  They travel through Earth carrying energy released by an earthquake.

What is the focus?

Answer:  The focus is the area beneath Earth’s surface where rock that was under stress begins to break or move.  This action triggers the earthquake.

What is the epicenter?

Answer:  The point on the surface directly above the focus is the epicenter.

Types of seismic waves:

1)   P Waves—The first waves to arrive are primary waves, or P Waves.  These waves compress and expand the ground like an accordion.

2)   S Waves—The secondary waves that come after the P Waves are S Waves.  These waves vibrate from side-to-side or up and down.

3)   Surface Waves—When P Waves and S Waves reach the surface, some of them become Surface Waves.  These move more slowly that P and S Waves, but they can produce severe ground movements.

How are earthquakes measured?

Answer:  Geologists measure earthquakes in two ways. 

1)   The amount of earthquake damage or shaking that is felt is rated using the Modified Mercalli Scale.

*The Modified Mercalli Scale rates the amount of shaking from an earthquake.  It is rated by people’s observations, without the use of instruments.  This scale is used in regions where there aren’t many instruments to measure an earthquake.  It uses Roman numerals to rate the damage and shaking at any given location.

2)   The magnitude (SIZE) of an earthquake is measured on a seismograph using the Richter Scale or the Moment Magnitude Scale.

*An earthquakes magnitude (size) is a single number that geologists assign to an earthquake based on the earthquake’s size. 

*THE EARLIEST MAGNITUDE SCALE IS CALLED THE RICHTER SCALE.

*The Moment Magnitude Scale rates the total energy an earthquake releases.

A magnitude of below 5 is a small earthquake and causes little damage.

A magnitude above 6 is a large earthquake and can cause great damage.

The most powerful earthquakes, with a magnitude of 8 or above, are rare and cause tremendous damage.

How is an epicenter located?

Answer:  Geologists use seismic waves to locate an earthquake’s epicenter using data from thousands of seismograph stations set up all over the world.

How do seismographs work?

Answer:  Seismic waves cause a simple seismograph’s drum to vibrate, which in turn causes the pen to record the drum’s vibrations.  The suspended weight with the pen attached moves very little.  This allows the pen to stay in place and record the drum’s vibrations.  The rest of the seismograph is anchored to the ground and vibrates when seismic waves arrive.

What is a seismogram?

Answer:  The pattern of lines, called a seismogram, is the record of an earthquake’s seismic waves produced by a seismograph.

What patterns do seismographic data reveal?

Answer:  Geologists have created maps, by using seismographic data, of where earthquakes occur around the world to show that earthquakes often occur along plate boundaries.

Where in the United States are the possibilities of major earthquakes more likely?

Answer:  Plates meet along the Pacific coast in California, Washington state, and Alaska, causing many faults. 

Chapter 3 Study Guide Covering "Plate Tectonics"---TEST WILL BE ON TUESDAY, NOVEMBER 15TH!!!!!

Chapter 3 – Plate Tectonics – Study Guide

·        Know all your vocabulary.  Be able to match each definition to the word it defines.

·        Describe Alfred Wegener’s hypothesis about the continents.

Answer:  Wegener’s hypothesis was that all the continents were once joined together in a single landmass and have since drifted apart.  Wegener was a German scientist, and his hypothesis was formulated in 1910.

·        What name did Wegener give the supercontinent, or single landmass, that existed about 300 million years ago?

Answer:  Pangaea

·        What evidence did Wegener suggest supported his hypothesis?

Answer:  He pieced together maps of Africa and South America, and noticed that mountain ranges on the continents line up.  He also noticed that coal fields in Europe and North America also match up.  Also, Wegener used fossils to support the hypothesis because they contained fernlike plants and freshwater reptiles found in places now separated by oceans.  The plants couldn’t have grown today in some of the places the fossils were discovered, and the reptiles couldn’t have swum the distance across the oceans.

·        More evidence confirming the hypothesis of the continental drift was published in 1957 by geologist Marie Tharp.  What evidence did she present?

Answer:  Data taken from ships showed how the height of the ocean floor varied, and that in certain places the floor of the ocean appeared to be stitched together like the seams of a baseball.  The seams formed mountain ranges that ran along the middle of some ocean floors.  These were called mid-ocean ridges.

·        What device using sound waves to measure the distance to an object was used in the mid-1900s by scientists to map mid-ocean ridges?

Answer:  sonar

·        Describe the process of sea-floor spreading.

Answer:  Sea-floor spreading begins at a mid-ocean ridge, which forms along a crack in the oceanic crust.  Along the ridge, new molten material from inside Earth rises, erupts, cools, and hardens to form a solid strip of rock.  More crust is added to the ocean floor.  At the same time, older strips of rock move outward from either side of the ridge.

·        Name 3 types of evidence that geologists have found for sea-floor spreading.

Answer: 

1-Ocean-floor Material shows rocks shaped like pillows that only form when molten material hardens quickly after erupting under water.

2-Magnetic Stripes-as magma erupts, cools, and hardens, magnetic minerals inside the rock line up in the direction of Earth’s magnetic poles.  The pattern of magnetic stripes on one side of a mid-ocean ridge is usually a mirror image of the pattern on the other side of the ridge.

3-Drilling Samples-Rock samples from the ocean floor show that the farther away from a ridge a rock sample was taken, the older the rock was.  The youngest rocks were always found at the center of the ridges.

·        What happens at deep-ocean trenches?

Answer:  In a process taking tens of millions of years, part of the ocean floor sinks back into the mantle at deep-ocean trenches.

·        Explain subduction.

Answer:  Crust closer to a mid-ocean ridge moves away from the ridge and toward a deep-ocean trench.  The new oceanic crust is hot, but as it moves away from the mid-ocean ridge, it cools.  As it cools, it becomes more dense.  Eventually, as it moves, the cool, dense crust might collide with the edge of a continent.  Gravity then pulls the older, denser oceanic crust down beneath the trench and back into the mantle.  This is called subduction.

·        Earth’s plates meet at boundaries.  What are the three types of boundaries?  Explain each.

Answer:

1.   Divergent Boundary-plates that move apart, or diverge from each other;

2.   Convergent Boundary-plates that come together, or converge;

3.    Transform Boundary-plates that slip past each other, moving in opposite directions.  The sides of the plates are rocky and jagged, so the two plates can grab each other and “lock” in place.  Forces inside the crust can cause the two plates to unlock.  Earthquakes often occur when this happens.  Crust is neither created or destroyed at transform boundaries!!!!!

·        What is the ‘theory of plate tectonics’?

Answer:  It states that Earth’s plates are in slow, constant motion, driven by convection currents in the mantle.

Making and Eating Edible Igneous, Sedimentary, and Metamorphic Rocks!

Study Guide for Chapter 2 "Rocks and Minerals"---Test on Tuesday, October 18th

Hello Parents and Students!

Today a hard copy of the Study Guide was sent home with the students in our class.  Please use it to prepare for the test covering Chapter 2 "Rocks and Minerals" on Tuesday, October 18th!  Good luck!  Mrs. Stafford

Study Guide – Chapter 2 Test—Minerals and Rocks

KNOW ALL OF YOUR VOCABULARY!!!  TAKE HOME YOUR VOCABULARY FOLDER!!!

THERE WILL BE A MATCHING OR SHORT ANSWER QUESTION FOR THESE WORDS!!!

Minerals—natural occurring solids that can form by inorganic (not living) processes and that have a crystal structure and a definite chemical composition!

For a substance to be a mineral, it must have all five of these characteristics:

1-naturally occurring

2-solid

3-crystal structure

4-forms by inorganic processes

5-definite chemical composition

QUARTZ is a mineral!

How are minerals identified?

Answer:  Each mineral has characteristic properties that can be used to identify it.  These properties are:

1-color

2-streak-the color of its powder

3-luster-how light is reflected from a mineral’s surface

Types of luster are:

-metallic

-silky

-waxy, greasy, earthy, or pearly

-glassy

4-hardness

THE HARDEST MINERAL IS A DIAMOND!

5-density—mass in a given space

6-crystal structure

8-cleavage and fracture

9-special properties—Examples:  Calcite bends light to produce double images!  Some minerals conduct electricity, glow when placed under ultraviolet light, or are magnetic.

How do minerals form?

1-organic materials

2-minerals from solutions

3-minerals from magma and lava

How do geologists classify rocks?

Answer:  To study a rock sample, geologists observe the rock’s mineral composition, color, and texture.

What are the three major groups of rocks?

1-igneous—forms from the cooling of magma or lava—Magma hardens underground to form rock.  The lava erupts, cools, and hardens to form rock on the Earth’s surface.

2-sedimentary--forms when small particles of rocks or the remains of plants and animals are pressed and cemented together—Forms in layers that are buried below the surface.

3-metamorphic—forms when a rock is changed by heat or pressure, or by chemical reaction.  Most metamorphic rocks form deep underground!

How do geologists classify igneous rocks?

Answer:  Igneous rocks are classified by their:

1-origin—Igneous rocks may form on (extrusive igneous rock) or beneath (intrusive igneous rock) the Earth’s surface!

BASALT IS THE MOST COMMON EXTRUSIVE ROCK!

GRANITE IS THE MOST ABUNDANT TYPE OF INTRUSIVE ROCK IN CONTINENTAL CRUST!

2-texture—the texture depends on the size and shape of its mineral crystals (except the different types of volcanic glass—igneous rocks that lack a crystal structure).

3-mineral composition—The silica content of magma and lava can vary.  Lava that is low in silica usually forms dark-colored rocks such as basalt!  Magma that is high in silica usually forms light-colored rocks such as granite!

How are igneous rocks used?

Answer:  Igneous rocks are used as tools and building materials.

How do sedimentary rocks form?

Answer:  Most sedimentary rocks are formed through a sequence of processed:

1-weathering

2-erosion

3-deposition

4-compaction

5-cementation

What are the three major types of sedimentary rocks?

1-clastic rocks-formed when rock fragments are squeezed together

2-organic rocks-formed where the remains of plants and animals are deposited in layers

3-chemical rocks-formed when minerals dissolved in a water solution crystallize

How are sedimentary rocks used?

Answer:  Sedimentary rocks have been used throughout history for tools and building.

What are metamorphic rocks?

Answer:  Any rock that forms from another rock as a result of changes in heat or pressure (or both heat and pressure) is a metamorphic rock.

How are metamorphic rocks classified?

Answer:  Geologists classify metamorphic rocks according to the arrangement of the grains making up the rocks.

Foliated rocks—describes the thin, flat layering found in most metamorphic rocks.

Examples of foliated rocks:  gneiss and slate

Nonfoliated rocks—the mineral grains in these rocks are arranged randomly.

Examples of nonfoliated rocks:  marble and quartzite

How are metamorphic rocks used?

Answer:  The metamorphic rocks marble and slate are important materials for building and sculpture.

What is the rock cycle?

Answer:  The rock cycle is a series of processes that occur on Earth’s surface and in the crust and mantle that slowly change rocks from one kind to another.

Example:  Weathering can break down granite into sediment that later forms sandstone!

Chapter 1 Study Guide for Test on Tuesday, September 20th

Study Guide

Earth Science

Chapter 1

Describe the inner core.

Answer:     The inner core occupies the center of the Earth.  It is iron and nickel and is also extremely hot.  However, pressure within the inner core is so great that it remains a solid.

Describe the outer core.

Answer:  The outer core is hot, molten iron and nickel under extreme pressure.  Convection currents cause movements in the liquid outer core.  Scientists hypothesize (assume or guess) that these movements cause Earth’s magnetic field.  The outer core surrounds the inner core, which occupies the center of the Earth.

Explain why a topographical map has a key.

Answer:  The key lists the symbols used on the map and their meanings.  Symbols are used to show features on Earth’s surface.  Without the key, a person does not know what the symbols on the map stand for.  An important part of the key on a topographic map is the statement of the map’s contour interval.  The contour interval enables the map user to determine elevation, relief, and slope based on the contour lines.

Compare and contrast maps and globes.

Answer:  Maps and globes both show the shape, size, and position of the features on Earth’s surface.  Both are drawn to scale and use symbols to represent topography and other features.  A globe is a sphere that represents Earth’s entire surface.  A map is a flat model of all or part of Earth’s surface as seen from above.  Maps distort the shape or size of features because they are projections of Earth’s curved surface onto a flat surface.

Explain how heat is transferred inside Earth through convection currents.

Answer:  Large amounts of heat are transferred to Earth’s mantle from Earth’s core and the mantle itself.  Heat and pressure inside the mantle cause solid mantle rock to warm and slowly rise toward the lithosphere.  When the rising rock cools, it becomes denser (packed tightly together) and sinks back through the mantle.

Which layer of the Earth is made up partly of cruse and partly of mantle material?

Answer:  the lithosphere

Holes drilled several kilometers into Earth’s crust provide DIRECT EVIDENCE about the Earth’s interior in the form of rock samples.

Starting from the surface, what is the correct order of Earth’s layers?

Answer:  crust, mantle, outer core, inner core

What is the transfer of energy through empty space called (like the sun transferring light and heat through the air)?

Answer:  radiation

It would always be easy to walk up a slope represented by contour lines that are?

Answer:  far apart

What units do scientists use to locate positions on the Earth’s surface?

Answer:  degrees

The feature of a map that relates a distance on the map to a distance on Earth’s surface is called?

Answer:  scale

Using one or more of your senses to gather information, such as examining a rock to see what minerals it contains, is called what?

Answer:  observing

Which part of the Earth contains plates?

Answer:  lithosphere

What term describes the difference in elevation between the highest and lowest parts of an area?

Answer:  relief

Other than using rock samples through direct evidence, how do geologists learn about Earth’s interiors through INDIRECT EVIDENCE?

Answer:  seismic waves

What is the diverse way scientists study the natural world and propose explanations based on the evidence they gather called?

Answer:  scientific inquiry

What is the latitude of the North Pole?

Answer:  90 degrees north

What is a spherical model of Earth’s entire surface called?

Answer:  a globe

An area’s topography is determined by?

Answer:  the area’s elevation, relief, and landforms

Suggestions:

·        Study your definitions in your science folder. 

·        Review elevation, relief, and landforms.  Pages 22-23

·        Review latitude and longitude, and how the equator and Prime Meridian determine locations. Pages 34 and 35

·        Review contour lines, index contour, and contour intervals.  Page 37

·        Remember, too, that a depression on a map is marked with a closed loop with dashes inside.  This means there is a hollow in the ground (low ground area).  Page 39