Change to the world and its atmosphere


HideShow resource information
  • Created by: Srilanka
  • Created on: 28-03-11 21:10
Preview of Change to the world and its atmosphere

First 312 words of the document:

Changes to the Earth and its atmosphere
The Earth has a layered structure, including the core, mantle and crust. The crust and Comment [M1]: The Core is the
innermost part of the Earth.
upper mantle are cracked into large pieces called tectonic plates. These plates move slowly, but
Comment [M2]: The mantle is a zone
can cause earthquakes and volcanoes where they meet. The Earth's atmosphere has changed over of hot rock in the interior of the Earth,
located between the outer crust and the
billions of years, but for the past 200 million years it has been much as it is today. molten core.
Comment [M3]: The outer layer of
the Earth, on top of the mantle. It is
The structure of the Earth between 6 and 48 kilometres thick and
includes the continents and the ocean
Cross Section showing structure of the Earth
The Earth is almost a sphere. These are its main layers, starting with the outermost:
1. Crust:- relatively thin and rocky
2. Mantle:- has the properties of a solid, but can flow very slowly
3. Outer core:- made from liquid nickel and iron
4. Inner core:- made from solid nickel and iron
! Note that the radius of the core is just over half the radius of the Earth. The core itself consists of
a solid inner core and a liquid outer core.
Plate tectonics
The Earth's crust and upper part of the mantle are broken into large pieces called tectonic
plates. These are constantly moving at a few centimetres each year. Although this doesn't sound
like very much, over millions of years the movement allows whole continent to shift thousands of
kilometres apart. This process is called continental drift.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

The plates move because of convection currents in the Earth's mantle. These are driven by
the heat produced by the decay of radioactive elements and heat left over from the formation of the
Where the tectonic plates meet, Earth's crust becomes unstable as the plates push against
each other, or ride under or over each other. Earthquakes and volcanic eruptions happen at the
boundaries between plates, and the crust may `crumple' to form mountain ranges.…read more

Page 3

Preview of page 3

Here's a taster:

It is clear that the main gas is nitrogen. Oxygen- the gas that allows animals and plants to
respire, and fuels to burn- is the next most abundant gas. These two gases are both elements and Comment [M4]: To engage in
respiration- the energy- producing
account for about 99% of the gases in the atmosphere. process inside living cells.
The remaining gases, such as carbon dioxide, water vapour and noble gases such as argon,
are found in much similar proportions.…read more

Page 4

Preview of page 4

Here's a taster:

The main uses of the noble gases
Noble Gas Main Use
Helium Used in balloons and airships. It is much less
dense than air, so balloons filled with it float
Helium balloons
Neon Used in advertising signs, it glows when
electricity is passed through it. Different
coloured neon lights can be made by coating the
inside of the glass tubing of the lights with other
Neon tube
Argon Used in light bulbs.…read more

Page 5

Preview of page 5

Here's a taster:

The early atmosphere:-
Scientists believe that the Earth was formed about 4.5 billion years ago. Its early
atmosphere was probably formed from the gases given out by volcanoes. It is believed that there
was intense volcanic activity for the first billion years of the Earth's existence.
The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There
were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most
of the water vapour condensed and formed the oceans .…read more


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »