中学生活与科学 2 学生用书PDF电子书下载

4 Energy 2

4.1 Different Forms of Energy 2

4.2 Energy Changes 7

4.3 Fuels 15

4.4 Generating Electricity 24

4.5 Energy and Us 36

Summary 41

Glossary 41

Key Points 42

Test yourself 44

5 Water 52

5.1 Water Purification 52

5.2 Further Treatment of Water 62

5.3 The Water Cycle 67

5.4 Water Conservation and Pollution 75

5.5 Dissolving 88

5.6 Growing Crystals 97

5.7 Solvents Other than Water 101

Summary 104

Glossary 104

Key Points 105

Test yourself 108

6 Matter 115

6.1 States of Matter 115

6.2 Particle Theory of Matter 125

6.3 The Particle Model 133

6.4 Gas Pressure 139

6.5 Density 145

6.6 Expansion and Contraction 153

Summary 164

Glossary 164

Key Points 165

Test yourself 168

Index 172