Science at key stage 3    (Year 7)

• Review pupils' understanding of the word 'fuel'.
• Ask pupils What fuels can you name and what do we use them for? This leads to a general statement that when fuels burn they make things happen. Introduce the definition of 'energy' as what burning fuels release to make things happen.

• Demonstrate and then instruct pupils in the safe use of the Bunsen burner and associated heating equipment. Tell pupils they are going to explore the output from natural gas fuel with the Bunsen burner set at different flames by measuring the temperature rise of a fixed volume of water in a beaker. Ask pupils to decide which factors they should keep the same in order to make a fair comparison.

• Ask for examples of uses of different fuels. Discuss with pupils how to carry out a fair test of which is the best fuel, eg liquid fuels (alcohols) in 'spirit burners', or solid fuels for camping stoves. Burn the fuel and record the temperature rise of water as a cooperative whole-class demonstration. Ask pupils to discuss how good they think the results are. Encourage pupils to consider factors which have not been controlled that may affect the results, and to consider possible errors of measurements.

• Show pupils fossil fuels, eg pieces of coal, sealed samples of artificial crude oil, and ask them what they know of their origins and that of natural gas. Build on this by:
• providing appropriate resources, eg video of how fossil fuels were formed, their extraction and present-day uses; a range of secondary sources including ICT (CD-ROM or internet)
• setting a clear task to present some aspects of the topic, eg a poster on the formation of fossil fuels or how our use of fossil fuels has changed; a simple drama or narrative such as 'From trees and T-Rex to fossil fuels', based on information from the video or other secondary sources
• discussing a question about the future use of fuel, eg As these fuels are non-renewable, will there be enough fuel in the future? Discuss what could be done and how pupils can contribute to conserving fuel supplies. Focus on what that could mean for pupils' lifestyles, eg walking to school, wearing warmer clothes, going to bed at dusk. Ask pupils to prepare a leaflet to explain the issues to year 6 pupils

• Some pupils will probably have suggested renewable resources in the previous discussion. Ask pupils what they know, and support this, eg show a video of the range of types of renewable energy resources.
• Demonstrate the use of a device and discuss the role of the renewable resource, eg solar cells transform solar energy into electrical energy by driving a small motor, solar panels transfer solar energy to water, running water on a turbine, etc.

• Show pupils images of solar panels and help them to identify key features, eg large surface, black colour, contain water.
• Tell them they are going to use black and silver trays of various sizes, eg aluminium 'takeaway' containers, containing the water and covered with clingfilm, to see which rises in temperature by the greatest amount over the length of the lesson if left in the sun. Use a microscope bench lamp if there is no sunlight. A datalogger could be connected in order to look at the relative changes in temperatures dynamically. Ask pupils to decide what factors they need to control to make a fair comparison and to predict which of their containers will show the greatest temperature rise, giving their reasons. Discuss their results with them and ask them to think again about the predictions they made and, if appropriate, why they weren't supported by the evidence.

• Provide pupils with access to up-to-date resources on energy provision and the work of scientists in developing these. Ask them to propose a useful device for the future. Encourage creative approaches, but based on science, eg giant windmills, solar collectors in space. This work could then be used to generate discussion on the pros and cons of renewable energy sources. The discussion could be extended to compare the needs and current energy use of western and less-developed nations.

• Brainstorm pupils' understanding of the word 'energy', or ask them to work in pairs to write an answer to What is energy? Summarise the contributions by associating energy with changes.
• Help pupils construct a spider diagram, or concept map, covering the range of renewable and non-renewable fuels, their uses, advantages and disadvantages.

• Review with pupils their ideas about food as the energy resource for plants and animals. This will have been covered at key stage 2, although the word 'energy' will not have been used. Link this use of the word 'energy' to its use in situations they have just studied.
• Use pupils' knowledge of 'calorie counts' for slimming or body-building to introduce the idea of measuring energy input. Introduce the joule as the unit of energy. Demonstrate that it is quite a small unit, eg lifting an apple by 1 metre takes about 1 joule of energy. Look at the energy ratings of food, eg a chocolate bar. Ask pupils to consider the question If you ate the chocolate bar how high would you have to lift the apple before all the energy is used up? Tell them about the famous physicist John Tyndall, who worked out that the energy he needed to climb the Matterhorn was contained in a ham sandwich, so that was all the food he took with him.

• Ask pupils in groups to investigate the energy resource in foods, eg breakfast cereals, snack foods, crispbread and marshmallow, by burning them and measuring the rise in temperature of some water. To help pupils plan, remind them of the fuel enquiry at the beginning of this unit.
• Draw together results from different groups and ask pupils to suggest how results could be presented so that those of different groups could be compared. Ask pupils for results which do not fit the overall pattern and to suggest reasons for this.

• Ask pupils where the plants that produced the burnt foods get their energy from. Remind them of plants' need for light to grow. This will help elicit pupils' knowledge of how plants acquire energy for growth. Pupils will probably recall exceptions, eg carnivorous plants, fungi. Reinforce this by devising food chains for typical habitats and trace the energy source back to sunlight.

• Consolidate the learning of this unit by:
• setting up a class debate introducing the moral and social issues of energy use in the context of application of their scientific understanding. This could involve the use of 'role cards', eg the views of scientists of different specialisms, of consumers, members of conservation organisations and those concerned with developing countries , or
• extending the 'energy story' from key stage 2 by asking pupils to develop food chain diagrams so that they can show the network of energy from the Sun to a wide range of foods, fuels and devices and to all aspects of pupils' lives