Science at key stage 3    (Year 9)

• Use secondary sources, eg photographs, video clips, to remind pupils about sedimentation and ask them what else they think plays a role in soil formation. Establish that vegetation and soil animals are also important.
• Present pupils with information about different soils and show them soil-testing kits. Ask them to use secondary sources to find out why soils are acidic or alkaline, and to identify problems that this might cause and suggest possible cures.
• Ask pupils to use the kits to test local and other soils. Use secondary sources to identify plants often found in particular soil types, eg in the locality of the school, the implications of soil type for agriculture and effects on some plants, eg hydrangea colour. Help pupils to summarise what they have found out in a database and use this to produce an information sheet.

• As a quick introductory activity, remind pupils of earlier work on local rocks and building materials and ask them to describe changes and compile a list of possible causes. Reinforce by showing video clips and/or photographs of a wide range of non-local weathered buildings and/or rocks and ask pupils to suggest a range of factors affecting weathering, eg nature of rock, climate, local conditions of air, water, soil, position, vegetation cover.
• Ask pupils to identify factors that lead to extensive chemical weathering.

• Ask pupils what they know about the importance of carbon dioxide in the air to plants and animals from their work on photosynthesis, and remind them that the atmosphere contains carbon dioxide from natural sources. Provide pupils with a range of solutions, eg rainwater, water with dissolved carbon dioxide, water with dissolved sulphur dioxide, and ask them to carry out tests to rank them according to pH.
• Help pupils make a summary of the processes involved, eg as a flow diagram. Use video clips to illustrate how sulphur dioxide and oxides of nitrogen get into the air, eg through volcanic eruptions, burning of fossil fuels, and are transported away.

• Provide pupils with named samples of a number of rocks, including some sandstones and some carbonates, eg chalk, marble, and metals, eg zinc, iron, lead, together with a very dilute solution of sulphuric acid (to represent acid rain), and ask pupils to investigate the effect of the acid on the materials. Ask them to suggest how to make and record careful observations of small changes over a period of time. Ask pupils to contribute results to a class record and bring together all the results.

• Ask pupils to use reference materials to identify the effect of acid rain on plants and animals in a particular location, and to identify the source(s) of the acid rain.
• Ask them also to find out about ways, eg catalytic converters, sulphur precipitators, in which acidic emissions can be reduced. Summarise both sets of information in a class display or set of information cards.

• Invite an adult responsible for environmental matters, eg an environmental health officer, to talk about their work. Ask pupils to prepare questions to ask, eg about the way in which air quality and water pollution are monitored, how the information is made public, what is done when air pollution rises. Using the information from the talk and other sources, ask pupils to compile a summary sheet of what is done to protect their local environment, eg the air and water quality.

• Review with pupils ways in which quality of air and/or water is monitored or controlled and ask them whether they think there is more pollution, eg of air or of water, now than there was at a specific time in the past. Ask them to suggest the basis for their answers and then to think what evidence might be collected, eg photographs, public records, paintings, individual medical records showing outbreaks of disease, descriptions of domestic and working environments, Clean Air Act and other legislation. Consider a selection of available evidence and compare it with today's evidence. Ask pupils to decide whether the evidence is good enough to come to a firm conclusion, and to explain their decisions.

• Present pupils with selected and simplified information, eg on video, about global changes in climate and ask groups to use it to prepare answers to questions, eg
• Have there been climate changes in the past?
• What were the effects of these?
• Is the Earth warming up? What evidence is there for this?
• If the Earth is warming, what are the possible causes of this? What role does the burning of fossil fuels play? What evidence is there?
• Ask pupils to make brief presentations of their answers to the questions, making clear the evidence on which they are based. Ask other pupils to ask questions about the evidence.
• Discuss pupils' presentations with them and examine the ways in which fuel is used and the impact of this on the environment and ways in which fuel consumption might be usefully limited.

• Provide pupils with summary sheets about ways in which the environment is monitored and ask them to check their understanding using a series of prepared questions.
• Consolidate key points with pupils.