Contents 1
1．The Size of the Universe 1
2．The Stages of a Rocket 4
3．Mathemagic 7
4．Light 10
5．What Is It ？ 13
6．How Does Water Help Make Our Weather？ 17
7．The Speed of Sound 20
8．Expansion and Contraction of Solids 23
9．Solar Energy 27
10．Volcanoes 30
11．The English of Science 34
12．Sonar 38
13．Where Is Tomorrow？ 43
14．An Ocean of Air 47
15．Wind 51
16．Time and Calendar 54
17．Our Food 57
18．Carbon Dioxide and Respiration 61
19．Measuring Temperature 65
20．The Importance of Rivers 70
21．Why Roses Are Red 74
22．A Trip to the Moon（Ⅰ） 78
23．A Trip to the Moon（Ⅱ） 82
24．You Push It，It Pushes You 86
25．Gravitation Everywhere 90
26．Heat 94
27．Living in the Atomic Age 97
28．Dangers in Space 102
29．A Blanket for the Earth 106
30．Weight and Mass 110
31．The Sun 113
32．The Food Factory 117
33．Fresh Water Factories 122
34．The Cell，the Body'S Building Material 126
35．What Holds a Satellite in Orbit 133
36．A Ruler to the Stars 136
37．Molecules，Atoms and Particles 142
38．Atoms Work for You 146
39．The Limits of the Environment 150
40．Collecting Heat from the Sun 157