Chapter 13 Science

Question 1

Explain the Big Bang Theory

Answer 1

Theory of how the Earth was made from materials in space colliding and where more dense materials went to the center and less dense materials floated to the top.

Question 2

Who are Alfred Wegener & Harry Hess?

Answer 2

Alfred Wegener is a scientist who proposed the theory of continental drift and plate tectonics. He theorized that the continents were “one big piece of land” and are slowly drifting away from each other. Harry Hess was a geological scientist who first proposed the theory of sea-floor spreading.

Question 3

What is Pangea?

Answer 3

A supercontinent

Question 4

What are the FOUR pieces of evidence of continental drift?

Answer 4

• The continents fit together like a puzzle
• Fossils of land or non-swimming organisms found on different continents
• Glacial deposits on warm continents/ warm weather plant fossils in the Arctic.
• Matching rocks and mountain ranges were found on different continents.

Question 5

What is SONAR?

Answer 5

Sound waves are produced and echoed off the ocean floor. The longer it takes the sound waves to return to the ship, the deeper the body of water.

Question 6

What are hydrothermal vents and how are they related to
chemosynthesis?

Answer 6

Hydrothermal vents are openings where magma forces up heat and chemicals. These vents are used for organisms that can’t get sunlight to use the chemicals to make their own food.

Question 7

What are TWO pieces of evidence of seafloor spreading?

Answer 7

• Older rock is found further away from the mid ocean ridge and younger rocks are
  closer
• Rock patterns show changes in magnetic poles

Question 8

What is the theory of plate tectonics?

Answer 8

The theory of plate tectonics is that the Earth’s crust and upper mantle are broken into plates that move along the asthenosphere and are caused by convection currents.

Question 9

What are the 3 different ways plates move?

Answer 9

Plates can move towards each other (convergent), away from each other (divergent), or slide past each other (transform).

Question 10

What are convection currents?

Answer 10

Hot magma from the center of the Earth rises to the surface of the Earth causing the plates to move. As the magma cools, it becomes more dense and it sinks back into the mantle.

Question 11

What are the tension and compression forces?

Answer 11

Tension forces are caused by continental plates moving away from each other.
Compression forces are caused when two continental plates move towards each other and push up.

Question 12

What are subduction zones?

Answer 12

Areas where an oceanic plate and a continental plate move towards each other and the oceanic plate subducts underneath the continental plate due to the difference in
densities

Question 13

Explain the difference between an earthquake, a seismic wave & a tsunami.

Answer 13

An earthquake is caused when energy is built up from heat and pressure under the
Earth’s surface and is released causing vibrations in the Earth’s crust. Seismic waves are earthquake waves that we feel. A tsunami is a wave caused by an earthquake that occurs on the ocean floor.

Question 14

What is the difference between an epicenter and focus?

Answer 14

The focus is a point inside the Earth where movement first occurs and energy is released.
The epicenter is the same point as the focus just located directly above it on the Earth’s surface.

Question 15

Explain the difference between the THREE types of waves measured in an earthquake.

Answer 15

Primary waves (P-waves) are the fastest type of waves that travel underground causing rocks to move back and forth. Secondary waves (S-waves) are slower arriving waves that travel underground causing rocks to move up and down. Surface waves (L-waves) are slower and larger waves that occur on the surface and cause the most destruction.

Question 16

What is a fault and explain the difference between the THREE types of faults.

Answer 16

A fault is a break that occurs when rocks break and results in movement of the land. A normal fault is when sections of rocks break from being pulled apart and move down due to divergent plate boundaries. A reverse fault is when sections of rocks break
from being squeezed together and move up due to convergent plate boundaries. A strike-slip fault is when sections of rocks break from shearing together and move back and forth due to transform plate boundaries.

Question 17

What is the difference between the Richter & Mercalli scale?

Answer 17

The Richter scale uses NUMBERS to measure the magnitude or strength of an earthquake by showing how much energy is released and is determined by the amplitude of the seismic wave. The Mercalli scale uses ROMAN NUMERALS to measure the amount of damage that has occurred depending on: the strength of the earthquake; the material the building is made of; the design of the structure and the distance from the
epicenter.

Question 18

What is the difference between plains, plateaus and mountains?

Answer 18

Plains are the most common landform with large, flat areas ideal for agriculture and have thick fertile soils and abundant grass for wildlife. Plateaus are flat, raised areas of land made up of rocks, cut through by river valleys and canyons. Mountains have the highest elevation of all the landforms and vary how they form.

Question 19

Explain the difference between the TWO types of plains.

Answer 19

Coastal plains are known as lowlands and are found near the ocean. Interior plains are known as the Great Plains that are found in the center of the U.S. and are flat, grassy, dry areas with trees.

Question 20

Explain the difference between FOUR types of mountains.

Answer 20

Folded mountains are formed when forces inside the Earth’s crust squeeze rock, causing them to fold like a rug pushed up against a wall. Upwarped mountains form when blocks in the Earth are pushed up by forces that can cause high peaks and sharp ridges. Fault-block mountains are made up of huge, tilted blocks that resemble steps and have majestic peaks and steep slopes. Volcanic mountains are formed when pressure from the heat causes lava to enter through a weak area in the Earth’s crust and layers of ash pile on
top of it.

Question 21

What are the parts of a volcano?

Answer 21

Magma is molten rock found inside the Earth’s surface. A crater is the hole at the top of a volcano. Lava is molten rock found outside of the Earth’s surface.

Question 22

What is tephra?

Answer 22

Tephra is rock or solidified lava that drops from the air in small pieces as ash and cinders or in large pieces as bombs or blocks.

Question 23

Explain the difference between THREE types of volcanoes.

Answer 23

Shield volcanoes are the largest type of volcanoes with a wide crater and gentle slopes formed from basaltic lava rich in iron and magnesium, found deep within the Earth, at divergent plate boundaries. Cinder-cone volcanoes are tall-standing, small cone volcanoes that have moderate to violent eruptions that do not last long, with lava shooting high into the air and stopping after all the gas is gone. Composite volcanoes are formed at subduction zones of converging plate boundaries resulting in steep slopes. They have violent tephra eruptions but quiet lava eruptions.

Question 24

What are hot spots?

Answer 24

Hot spots are large bodies of magma that are forced upward through the Earth’s mantle and crust producing active volcanoes. They help scientists identify plate movements including their speed and direction.