Earth's Changing Surface

Question 1

Comet

Answer 1

A comet is a ball of dust and ice that orbits the sun. 🌞☄

Question 2

Continental drift

Answer 2

The process of continents moving very slowly because of forces inside Earth is called continental drift. 🌍

Question 3

How did Earth change over hundreds of millions of years ?

Answer 3

Ref

Question 4

How long ago Earth formed

Answer 4

Earth formed roughly 4.6 billion years ago.🌎

Question 5

The Atmosphere

Answer 5

This was Earth’s second atmosphere. It was mainly composed of carbon dioxide, nitrogen,and water vapor. Collisions with comets added other gases. The ice in a comet consists of water and frozen gases, such as carbon dioxide. Volcanic eruptions released carbon dioxide, water vapor, nitrogen ,and other gases. ☄🗻

Question 6

Oceans

Answer 6

Water arrived to Earth through meteors that carried minute drops of water (over 20 million years). Earth’s surface was way too hot for water to remain there. All water evaporated into water vapor. When temperatures went down and the surface cooled, rainwater began to accumulate to make the first oceans. 🌊🌧

Question 7

Continents

Answer 7

More and more of Earth’s rock cooled and hardened. Less than 500 million years after Earth’s formation, the less dense rock at the surface formed large land masses called continents. 🌏

Question 8

How our planet got oxygen

Answer 8

About 2.5 billion years ago, many organisms began to using energy from the sun to make their own food(photosynthesis). One waste product of photosynthesis is oxygen. The amount of oxygen started to increase as more organisms began to release oxygen. Processes in the atmosphere changed some of this oxygen into a form of ozone. It blocked out some of the sun’s deadly UV rays, so animals could live on land.🌫🌬

Question 9

Convergent boundary

Answer 9

Because plates come together at the trenches, the trenches are called convergent boundaries.

Question 10

Subduction

Answer 10

When the denser plate of the two moves down into the interior of the Earth.

Question 11

Divergent boundaries

Answer 11

Because the plates move apartment at mid ocean ridges, the ridges are called divergent boundaries.

Question 12

Transform boundary

Answer 12

Boundaries formed by lateral faults are called transform boundaries.In this case, two plates grind together and slip past each other horizontally.

Question 13

Plate boundary

Answer 13

The boundary at which plates move past each other, collide, or diverge from one another.

Question 14

Compression

Answer 14

A type of stress that involves rocks being pushed together. 🌏🌰

Question 15

Tension

Answer 15

The type of stress that involves rocks being pushed away from one another.

Question 16

Shearing

Answer 16

The type of stress that involves rocks pushing past one another.

Question 17

Crust

Answer 17

The crust is the surface, or outermost, layer of the Earth.

Question 18

Lithosphere

Answer 18

The topmost solid part of the Earth that is made of a number of plates. The plates contain a little of the crust and a relatively large part of the mantle.

Question 19

Mantle

Answer 19

Mantle is the thick part that is located underneath the crust.

Question 20

Core

Answer 20

The center section of the Earth

Question 21

Convection current

Answer 21

A convection current is the movement of material caused by differences in temperature.

Question 22

Stress

Answer 22

The forces that are inside Earth that push and pull on the Earth’s crust.

Question 23

Deformation

Answer 23

The breaking, twisting, and folding of rocks is called deformation.

Question 24

Fracture

Answer 24

These stresses can also cause the rocks to fracture, or crack.

Question 25

Fault

Answer 25

A break or crack along which rocks move is called a fault.

Question 26

Rift Valley

Answer 26

Some valleys are formed when the block of land between two normal faults slides downward. Valleys created in this way are called rift valleys.

Question 27

Plate

Answer 27

The moving, irregularly-shaped slabs that fit together like paving stones to form the crust.

Question 28

The theory of plate tectonics

Answer 28

The theory of plate tectonics, which links together the ideas of continental drift and ocean-floor spreading, explains how the Earth has evolved over time. It helps to explain the formation, movements, collisions, and destruction of the Earth’s crust.