GCSE: Changing Materials - The Earth and its Atmosphere
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Key things you need to know about the atmosphere
- 1 The air around us is composed of 70% nitrogen, 29% oxygen and 1% other gases (mostly noble gases and 0.04% carbon dioxide)
- 2 Two of the best ways now being used to reduce carbon dioxide emissions are: “capture and storage”- where we capture the CO2 and trap it in abandoned oil wells. And “sequestration”- where we react the CO2 with CaO to make CaCO3 (CaO + CO2 = CaCO3)
- 3 The layer of atmosphere that we live in is called the troposphere. Above that is the stratosphere, followed by the mesosphere, then the thermosphere and finally the exosphere. The ozone layer is located in the lower stratosphere.
- 4 The ozone layer is a layer of O3 molecules that absorb harmful ultraviolet radiation that would otherwise kill most human life on Earth (by giving us cancer).
- 5 Gases like CFC’s (chlorofluorocarbons) destroy the ozone layer. It takes decades for CFC’s to be removed from the atmosphere once they are up there- and all the time they are constantly destroying more ozone. There is currently a hole in the ozone layer caused by gases like CFC’s that is as big as the arctic (north) pole…and growing.
Five top tips on pollution
- 1 Carbon monoxide is a toxic gas as it blocks the haemoglobin in our blood from transporting oxygen around our body…if you take in too much carbon monoxide you will suffocate even if you keep on breathing!
- 2 Nitrogen oxide and nitrogen dioxide gases in the atmosphere cause acid rain. This destroys trees and makes lakes too acidic for fish to live in. It is also responsible for corroding buildings.
- 3 Carbon dioxide is the biggest cause of global warming and if its levels are not reduced, it could cause the melting of the polar ice caps. This will flood an estimated minimum of 30% of England. It is the biggest worry of atmospheric scientists of our time.
- 4 Particulates, mainly found in car exhausts, get stuck in our lungs and cause cancer.
- 5 Low level ozone (O3) is incredibly dangerous, especially for people who have asthma.
What is global warming?
- 1 Global warming is caused by greenhouse gases absorbing infrared radiation emitted from the Earth and scattering it back down to Earth. As infrared radiation is basically heat, this heats the surface of the Earth up.
- 2 As well as carbon dioxide, other greenhouse gases include water and methane. They absorb the infrared radiation by making their bonds vibrate.
- 3 As global warming causes the polar ice caps to melt, clathrate deposits (huge amount of trapped methane gas) are released. This causes further global warming in a positive feedback loop.
- 4 As the average temperature on land raises, many crops will not be able to grow. Almost all scientists agree that this will cause widespread famine on a scale never seen before. This will affect all countries, not just developing countries.
- 5 A common mistake students make is to confuse the greenhouse effect with the hole in the ozone layer. Ozone has nothing to do with the greenhouse effect. Keep these two topics clearly separated in your mind.
239 GCSE Changing Materials - The Earth and its Atmosphere essays
- Marked by Teachers essays 6
- Peer Reviewed essays 19
This is a very detailed and comprehensive answer. An attempt has been made to evaluate the alternatives to fossil fuels and the writer has described how…
- Essay length: 1778 words
- Submitted: 21/02/2013
- Marked by teacher: Kathryn Bradley 06/06/2013
- Awarding body: Edexcel (for GCSEs)
A 4 star essay with good detailed scientific knowledge of a fertiliser. Some more general information would improve the introduction but there is a good balance of advantages and disadvantages…
- Essay length: 928 words
- Submitted: 13/07/2012
- Marked by teacher: Patricia McHugh 08/04/2013
An investigation to see how voltage affects The electrolysis in a copper Sulphate solution using copper electrodes.4 star(s)
This is a good experiment write-up. It has produced a good set of results and given valid reasons why the method was 'careless'. The evaluation was well done …
- Essay length: 1825 words
- Submitted: 19/02/2004
- Marked by teacher: Louise Star 21/06/2013
Why is Aluminium utilised in the contemporary world, for the construction of aircraft and rockets, more so than other metals and substances?3 star(s)
This essay has excellent features: a lot of material has been referenced and sourced correctly, and a good understanding of key chemical principles has been illustrated.
- Essay length: 1248 words
- Submitted: 25/02/2013
- Marked by teacher: Kathryn Bradley 06/06/2013
- Awarding body: Not known/Not applicable
This report has a very good introduction and a detailed, if poorly laid out method. However, there is no conclusion and the evaluation is very poor
Overall, this piece…
- Essay length: 1343 words
- Submitted: 21/02/2010
- Marked by teacher: Brady Smith 10/04/2013
This report has some interesting and useful information. However it also has some mistakes and is missing key pieces of information particularly surrounding the process of electrolysis itself.
- Essay length: 388 words
- Submitted: 19/08/2003
- Marked by teacher: Cornelia Bruce 01/12/2012
#1# The response is well laid out with excellent care taken to lay the essay out in a logical manner with care taken to explain the effects of each gas…
The response to the question is explicit and well thought out, the fact that the student has thought logically about the reasoning behind the argument for using bio-degradable plastics. Planning…
- Essay length: 731 words
- Submitted: 28/06/2009
- Reviewed by: cheekymokeyxxx 01/07/2012
Response to the question is done well and explains a variety of scientific principles well. The candidate could have included scientific equations and a diagram to show what is…
- Essay length: 688 words
- Submitted: 25/01/2005
- Reviewed by: skatealexia 03/08/2012