Energy Resources
Overview
Somebody, somewhere, had to decide what would be burnt or turned or heated to light the room you are sitting in. That decision was not made by a physicist alone. It weighed how much a kilogram of the stuff carries, whether it can be kept safely in a tank behind a building, what it does to the air of the town, what it leaves behind when the plant is dismantled in forty years, and whether it will still be there for your grandchildren. Every one of those questions has a physics answer underneath a political argument, and this lesson is about the physics.
You will learn to read a fuel as a store with a price tag: so many megajoules in every kilogram, kept in a particular way, dangerous in a particular way. You will keep an honest account of where those megajoules end up: so many reaching the job that was worth paying for, so many warming the neighbourhood instead, the two always adding back to what was burnt. You will see why two stoves burning different fuels can need six times as much mass for the same hot pot. Then you will step up to the national scale: what separates a renewable source from one that runs out, why renewable and harmless are not the same word, and what wave, solar and geothermal schemes are genuinely good and genuinely bad at.
Objectives
- Fuels are a useful store of energy; different fuels are suitable for different situations and are selected according to a range of factors, such as ease of storage, energy content and safety.
- When a fuel is used, some energy is transferred to the surroundings. Some fuels are more efficient than others.
- There is a range of energy sources used on a national and global scale. Their use has implications for society in terms of factors including renewability and the environmental impacts of extraction, use and disposal.
- A range of technologies have been developed to provide energy in a renewable way, such as wave power, solar power and geothermal power. Students should be aware of these and other examples and be able to identify advantages and drawbacks with their use.
Mind map
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Lesson Note
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Lesson Evaluation
Congratulations on completing the lesson on Energy Resources. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which of these is a renewable energy source? A. Coal B. Natural gas C. Geothermal D. Oil Answer: C
- A burner releases 40 MJ from each kilogram of its fuel and gets 12 MJ of that into the pot. How much energy reaches the pot when 2.0 kg of the fuel is burnt? A. 12 MJ B. 24 MJ C. 80 MJ D. 240 MJ Answer: B
- A hospital must have electricity all night. What is the main drawback of supplying it from solar panels alone? A. Solar panels release sulfur dioxide B. The output falls to zero at night, so storage or a second source is needed C. Solar panels can only be built where the rock below is hot D. Solar panels destroy the mudflats in an estuary Answer: B
- Hydrogen holds about 120 MJ per kilogram and diesel about 45 MJ per kilogram. Why is diesel still chosen for a standby generator? A. Burning diesel releases no carbon dioxide B. Diesel is a liquid at ordinary pressure, so far more energy fits into a plain tank C. Each kilogram of diesel releases more energy than each kilogram of hydrogen D. Hydrogen cannot be burnt in an engine Answer: B
- Which renewable source gives an output that can be predicted years in advance? A. Wind B. Solar C. Tidal D. Wave Answer: C
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Work through these questions in the app
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