about one-fifth (approximately 20%) oxygen proportions of various other gases, including carbon dioxide, water vapour and noble gases. 4.9.1.2 Theories about what was in the Earth’s early atmosphere, and how the atmosphere was formed, have changed and developed over time. Evidence for the early atmosphere is limited because of the time scale of 4.6 billion years. One theory suggests that during the first billion years of the Earth’s existence there was intense volcanic activity that released gases that formed the early atmosphere and water vapour that condensed to form the oceans. At the start of this period the Earth’s atmosphere may have been like the atmospheres of Mars and Venus today, No knowledge of other theories is required. appropriate information, interpret evidence and evaluate different theories about the Earth’s early atmosphere. WS 1.1, 1.2, 1.3, 3.5, 3.6, 4.1 1 Extended writing: describe the theory of the evolution of the Earth’s early atmosphere. Extended writing: explain why the composition of the atmosphere has changed over billions of years. Compare the Earth’s atmosphere to that of Mars and Venus. Video clips YouTube: YouTube: about ancient volcanoes, climate etc:
4.9.2.1 Greenhouse in the atmosphere maintain temperatures on Earth high enough to support life. Water vapour, carbon dioxide and methane are greenhouse gases. Describe the greenhouse effect in terms of the interaction of short and long wavelength radiation with matter. WS 1.2 2 Describe the effect of greenhouse on wavelength. Grade 9: explain why the wavelength changes due to greenhouse gases. Video clips YouTube: YouTube: (long video) 4.9.2.2 Some activities increase the amounts of greenhouse gases in the atmosphere. These include: carbon dioxide methane Based on peer-reviewed evidence, many scientists believe that human activities will cause the temperature of the Earth’s atmosphere to increase at the surface and that this will result in global climate change. However, it is difficult to model such complex systems as global climate change. This Recall two human activities that increase the amounts of each of the greenhouse gases carbon dioxide and methane. Evaluate the quality of evidence in a report about global climate change given appropriate information. Describe uncertainties in the evidence base. Recognise the importance of peer review of results and of communicating results to a wide of audiences. 1 Describe how greenhouse gases are produced. Evaluate the use of models for predicting climate change. Use the internet to obtain data for concentrations of greenhouse gases. Evaluate the reliability of the data available on the internet. Research the process of peer review in reporting results/data. Video clip YouTube:
cycle of a product, service or event. The carbon footprint can be reduced by reducing emissions of carbon dioxide and methane. Give reasons why actions may be limited. WS 1.3 reductions on the atmosphere and everyday life. A person’s carbon footprint can be calculated using a variety of sites such as: and calculated carbon footprint. 4.9.3 Common atmospheric pollutants and their sources Spec ref. Summary of the specification content Learning outcomes What most candidates should be able to do Suggested timing (hours) Opportunities to develop Scientific Communication skills Opportunities to develop and apply practical and enquiry skills Self/peer assessment opportunities and resources Reference to past questions that indicate success 4.9.3.1 The combustion of fuels is a major source of atmospheric pollutants. Most fuels, including coal, contain carbon and/or hydrogen and may also contain some sulfur. Describe how carbon monoxide, soot (carbon particles), sulfur dioxide and oxides of nitrogen are produced by burning 2 Write word equations for complete and incomplete combustion. Use equations to describe the reactions in terms of reactants, Video clips YouTube: YouTube:
The released into the atmosphere when a fuel is burned may include carbon dioxide, water vapour, carbon monoxide, sulfur dioxide and oxides of nitrogen. Solid particles and unburned hydrocarbons may also be released that form particulates in the atmosphere. Predict the products of combustion of a fuel given appropriate information about the composition of the fuel and the conditions in which it is used. WS 1.2 products made and number of each present. Explain why the following can be produced in combustion: carbon dioxide carbon monoxide soot water vapour sulfur dioxide oxides of nitrogen. 4.9.3.2 Carbon monoxide is a toxic gas. It is colourless and odourless and so is not easily detected. Sulfur dioxide and oxides of nitrogen cause respiratory problems in humans and cause acid rain. Particulates global dimming and health problems for humans. Describe and explain the problems caused by increased amounts of pollutants in the air. WS 1.4 1 Describe the effect of the following products: Carbon monoxide on the body. Sulfur dioxide and oxides of nitrogen on acidity of rain water. Sulfur dioxide and oxides of nitrogen on respiratory system. Particulates on global dimming. Particulates on human health problems.