《新综合科学 牛津原版 3》

Unit 13 Food and TransportSubstances in food2

Food tests3

Functions of food8

Balanced diet13

Storing food19

More about food chains and food webs25

Teeth27

Tooth decay32

Digestion36

Absorption of food　41

Digestive juices43

A closer look at the digestive system44

More about enzymes45

Transport system in mammals48

Pulse and pulse rate56

Blood pressure58

Water balance58

The kidneys and their functions61

Nutrients for plant growth64

Absorption and transport of water in plants68

Xylem and phloem72

The main uses of water in plants72

Summary73

Difficult words79

Unit 14　Materials from the EarthThe Earth82

The soil91

Building materials96

Metals from the Earth's crust101

The pollution problem107

Coal111

Crude oil or petroleum117

Materials from the sea124

Water pollution129

More materials from the sea131

Chalk,limestone and marble135

Summary137

Difficult words142

Unit 15　Electricity and ElectronicsElectrostatics144

The Van de Graaff generator146

Looking at atoms-a revision150

Pushing charges152

Voltage and the voltmeter154

Safety with the mains voltage158

Dynamo effect159

Alternating current and direct current166

Transmitting electrical energy166

Transformers171

Power transmission173

Using electricity174

Power and energy176

Current in gas179

Lightning180

Fluorescent lamps185

Current in a vacuum185

Diode187

C.R.O.and TV197

Some useful electronic components197

Switches205

Electronic logic212

Applications of the AND gate　219

Summary　222

Difficult words　227

Index　228