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Learning outcomes

After studying this unit you should be able to:

  • list the six key nutrient groups and explain their role in a healthy diet;

  • understand and calculate body mass index (BMI), and use such calculations to predict desirable weight ranges for individuals;

  • explain the importance of a balanced diet in terms of energy intake;

  • explain how genetic and environmental variables may interact to produce variability in human body weight and adiposity b
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2.4 Summary of Section 2

  1. The water cycle involves the movement of water, in all its forms, over, on and through the rocks near the surface of the Earth in a cycle. This cycle is driven by the Sun's energy and the Earth's gravity. The total volume of water in the cycle is virtually co
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2.2 Precipitation

Water that transfers from the atmosphere to the Earth's surface is called precipitation. It may be in the form of rain, snow or hail. Water vapour may also precipitate by condensing as dew or hoar frost. Water in the atmosphere, although one of the smallest reservoirs, is the most imp
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1.2 The economics of water

Water has traditionally been regarded as a free resource in the sense that there is nothing to stop anybody collecting their own supply of water from rainfall. Even water from the public supply is very cheap. Although sand and gravel only cost around £12 a tonne in the UK in 2004 (Argles, 2005), the average of £0.80 per tonne (a cubic metre) for supply of mains water in England and Wales is even cheaper. However, some regions of the world are less fortunate. For example, in Kuwait most fres
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Learning outcomes

By the end of this unit you should be able to:

Introduction

Most of us are probably more familiar with the Earth’s physical resources than we realise. They are basically those non-biological parts of our natural world that we can put to good use. In this unit we will help you to appreciate aspects of one particular physical resource - water use and the w
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9 Glossary

Click on the link below to open the unit glossary.

Open glossary now...


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7 Renewable and non-renewable energy supplies

Energy resources can be considered in a completely different way from their energy density
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6 Concentrating, storing and transporting energy

The Earth is awash with energy from sources other than fossil fuels; thousands of times as much a
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5 Nuclear energy

Einstein's famous equation E = mc2 shows that mass (m) and energy (E) are proportional to one another. The constant c2 linking the two is the square of the speed of light c (3 × 108 m s−1). Implicit in the equat
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4.1 Natural stores of carbon

The major natural stores of carbon (called ‘reservoirs’) are shown below in Figure 1.9.

2.3 Global power demand

In Section 2.2 we calculated a value of 14.3 TW for the average global requirement for primary power in 2002
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An introduction to energy resources

Understanding energy resources involves considering all types of energy source from various scientific
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Acknowledgements

The material acknowledged below is contained in Chapter 3 of An Introduction to Galaxies and Cosmology (eds Mark H Jones and Robert J Lambourne), published by the Press Syndicate of The University of Cambridge  in association with The Open University. Copyright © The Open University, 2003, 2004.

This publication forms part of an Open University course S282 Astronomy.


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