Science Test- Movements On The Earths Surface

Question 0

Characteristics of the earths crust?

Answer 0

It is 7-50 km thick and is made up of rocks and minerals. It is 70% covered by oceans. It is not smooth because it has hills, mountains valleys and deserts.

Question 1

Composition of the earths crust?

Answer 1

Crust, mantle, outer core and inner core

Question 2

Characteristics of the mantle?

Answer 2

It is 2800m thick and the temperatures near the crust are 500 degrees but further down near the Core is 3000 degrees. Near the crust it is slowly moving due to convection currents and the bottom is solid.

Question 3

Characteristics of the core?

Answer 3

The core is the centre of the earth and it consists of the inner core and outer core. The outer core is made mainly of metals; not rock which is iron with some nickel. Temperatures rage from 4000-6000 degrees. The inner cores temperature is almost 10000 degrees and is solid.

Question 4

Characteristics of Continental crust?

Answer 4

Continental crust is less dense than oceanic crust, but is considerably thicker (ranging from 35-40 km). The type of rock which makes up the crust is granite and is covered by hills, mountains, valleys and deserts.

Question 5

Characteristics of oceanic crust?

Answer 5

Oceanic crust is more dense than continental but is less thicker ranging from 7-10 km. it is made up of basalt covered by oceans.

Question 6

What is the age of the earth?

Answer 6

It is about 4.54 billion years old.

Question 7

What is the continental drift?

Answer 7

The continental drift is the theory that all the continents were once joined forming a super continent called Pangea. It is proposed that it is to have existed about 220 million years ago.

Question 8

Who developed this theory?

Answer 8

Alfred Wenger.

Question 9

What is the evidence supporting the continental drift?

Answer 9

1. Continents appear as if they would fit together like a jigsaw puzzle (particularly South America and Africa)
2. Fossils of the same species that could not fly/walk/swim that distance were found on separate continents.
3. Evidence of coal (created from debris of rainforest over millions of years) found in dry areas.
4. Evidence of glacier scratches on rocks found in now dry snow-free areas.

Question 10

Movements of continents throughout time (Pangea, Gondwana and Laurasia?

Answer 10

250 million years ago
-Pangea , super continent
180 million years ago
-Pangea begins to break up to form Laurasia and Gonwanaland
135 million years ago
-South America and Africa begin to move away from Australia and Antarctica. India begins to move away as well.
65 million years ago
Australia and Antartica begins to move apart

Question 11

What is the tectonic plate theory? How does it relate to the continental drift theory.

Answer 11

Combination of two theories: continental drift and sea floor spreading. It means the earths crust is broken up into large plates which are slowly moving , leading the continents on them to move.

Question 12

What are tectonic plates.

Answer 12

They are large areas of the earths crust that may include continent and/or sea floors. They are slowly moving as the float on the semi-liquid magma at the top of the mantle.

Question 13

Types of plate boundaries?

Answer 13

Transform-when two plates slide past each otherwhich can potentially cause an earthquake is plates become jammed.
Converging- when two plates move towards each other. Continental&continental edge of plates crumble and push up to form mountains. Oceanic and continental, oceanic crust returns to the mantle and forms a line of volcanoes and mountains. Oceanic and oceanic, the older denser crust subducts under the newer crust, creating an ocean trench and a line of undersea volcanoes which can form an island arc.
Diverging-when two plates spread apart which can occur in the middle of the ocean causing sea floor spreading and oceanic trenches, or in the middle of last causing a Rift Valley of mid ocean ridge. Sometimes associated with volcanoes

Question 14

What is subduction

Answer 14

When one tectonic plate is pushed downwards towards the mantle under another.

Question 15

What is sea-floor spreading?

Answer 15

Proposed by Harry Hess- convection currents deep inside the mantle caused spreading plates to move apart.it occurs mid ocean ridges where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.

Question 16

Convection currents?

Answer 16

Movement in liquids or gases caused by the rising of hot materials.

Question 17

Australia’s location tectonic plate wise?

Answer 17

We are pretty much in the middle of the I do-Australian plate meaning we would have minimal volcanic or earthquake action

Question 18

What is magma?

Answer 18

A hit semi-liquid Rock that comes up from the mantle.

Question 19

What is lava?

Answer 19

Hot molten of semi-liquid Rock that erupted from a volcano of fissure.

Question 20

Organisms that spent the longest and shortest time on earth?

Answer 20

Longest- bacteria, algae and fungi

Shortest- humans

Question 21

Recent to oldest era?

Answer 21

Pre-Cambrian-570+
Paleozoic- 245-570
Mesozoic-65-245
Cainozoic-0-65

Question 22

What is a fossil?

Answer 22

A remain or imprint of animals or plants preserved in rocks.

Question 23

How are fossils created?

Answer 23

Usually found in sedimentary rocks and formed by the deposition of layers in the sediments such as mud silt or Sand.

Question 24

How to date fossils?

Answer 24

Rocks with simple animals are older and more complex or more recent.

Question 25

What is comparative dating?

Answer 25

Where geologists place rocks and date fossils based on surrounding fossils fossils in the lower/higher bands of sediments.

Question 26

What is radioactive dating?

Answer 26

It is a more accurate measure of the age of fossils as we measure the amount of radioactivity in the fossil by comparing the amounts of lead and uranium are in it

Question 27

What is a petrified fossil?

Answer 27

Chemicals which make up bones shells and other hard parts of ancient organisms are often replaced by minerals from surrounding rock. This happens over millions of years. The fossil is usually harder than surrounding rocker and is considered petrified. When the rocks erodes the fossil is exposed.

Question 28

Carbonised fossils?

Answer 28

Rocks in which dead organisms are trapped are subjected to extreme heat and pressure causing chemical changes to occur and all of the materials in organisms body except carbon convert to gases. Usually the fossil is black

Question 29

Unaltered fossils

Answer 29

Unaltered fossil

Question 30

Moulds and casts

Answer 30

Remains of an organisms trapped in sediments decompose over a long time inside a rock leaving a cavity inside the rock called a mould in the exact shape of the organism. Sometimes surrounding liquids seep in and refill it hardening and forming a cast

Question 31

What is a Rift Valley?

Answer 31

A steep sided valley formed by the downward displacement of a block of the earths surface between nearly parallel faults or fault systems.

Question 32

What is an ocean trench?

Answer 32

A long, narrow deep depression in the ocean bed, typically one running parallel to a plate boundary and marking a subduction zone

Question 33

What is a mid-ocean ridge?

Answer 33

A long, seismically active submarine ridge system situated I’m the middle of an ocean basin and marking the site of the upwelling of magma associated with sea floor spreading