Changes In The Earth's Atmosphere

Question 1

The earth’s crust and the upper part of the mantle are cracked into…

Answer 1

Large pieces (tectonic plates)

Question 2

What doe convection currents cause?

Answer 2

Convection currents with in the earth’s mantle driven by heat released by natural radioactive processes cause that plates to move at relative speeds of a few centimetres per year?

Question 3

What can the movement of tectonic plated cause?

Answer 3

The movements can be sudden and disastrous. Earthquakes and/or volcanic eruptions occur at the boundaries between tectonic plates

Question 4

For 200 million years, the proportions of different gases in the at ostphere have been the same as they are today, which are:

Answer 4

Nitrogen-80%
Oxygen-20%
Small portions of various other gasses, including CO2, water vapour and nobel gases

Question 5

What happened during the first billion years of the earth’s existence?

Answer 5

There was intense volcanic eruptions. This activity released the gases that formed the early atmosphere and water vapour that condensed form the oceans

Question 6

Give one theory if how the atmosphere was formed.

Answer 6

One theory suggests that during this period the earth’s atmosphere was mainly CO2 and there would have been little or no oxygen gas (like the atmosphere of Mars and Venus today). There may also have been water vapour and small proportions of methane and ammonia

Question 7

What is Miller-Urey’s theory of how life was formed?

Answer 7

2 scientist sealed a mixture of H2O, ammonia, hydrogen and methane in a sterile flask. The mixture was heated to evaporate the water to produce water vapour and gases, simulating lighting. After a week, contents were analysed. Amino acids, the building black of proteins were found.

Question 8

How is oxygen produces in our atmosphere today?

Answer 8

Plant and algae produce oxygen through the process of photosynthesis

Question 9

What happened to most of the carbon from carbon dioxide in the air?

Answer 9

They gradually c

Become locked up in sedimentary rock as carbonates or fossil fuels

Question 10

What do oceans act as?

Answer 10

They act as a reservoirs for CO2 but increases amounts of CO2 absorbed by the ocean has an impact on the marine environment

Question 11

How is CO2 released nowadays?

Answer 11

By burning fossil fuels increases the level of CO2 in the atmosphere

Question 12

What is air?

Answer 12

It is a mixture of gases with different boiling points and can be fractionally distiller to provide a source of raw materials used in a variety of industrial processes

Question 13

What does the eath’s crust consist of?

Answer 13

Core
Mantle
Crust
And is surrounded by the atmosphere

Question 14

What is locked up carbon?

Answer 14

Carbon dioxide from the air/atmosphere forms rocks or fossils in sedimentary rocks

Question 15

Why do tectonic plates move?

Answer 15

Radioactive decay in the earth’s crore heats the mantle and causes convections currents (in the mantle) as a result the tectonic plates move which are found on the earth’s crust

Question 16

How are earthquakes/tsunamis formed?

Answer 16

Plates moving passed each other due to convection currents

Question 17

Why can we not predict earthquakes?

Answer 17

We cannot monitor activity below the earth’s crust

Not every plate movement leads to an earthquake

Question 18

Why has oxygen levels gone up?

Answer 18

Plants have developed and carry out more photosynthesis

Question 19

Why has carbon dioxide levels gone down?

Answer 19

Absorbed by the ocean

Taken in in photosynthesis

Question 20

Why has nitrogen levels gone up?

Answer 20

Ammonia out of volcanoes

Question 21

Why has levels of water vapour decreased?

Answer 21

Condensed into oceans as temperature goes down

Question 22

Who are gases obtained from the air?

Answer 22

They are obtained from the air by fractional distillation because they cool down and they will condense at their own boiling point