CHAPTER II 

 MATTER AND ITS PROPERTIES 



OUR previous study of geography has given us some 

 ideas of the material or matter of which the world is com- 

 posed. Matter is defined as anything which occupies 

 space. A substance is any particular kind of matter. 

 The earth is composed of many different substances 

 rocks and soils, water, air, and various forms of animal life 

 that use the soil, the water, and the air to sustain their 

 lives. 



Matter exists in three different forms, namely : solids, 

 liquids, and gases, and all the substances of the earth exist 

 in one or more of these forms. Many solids may be 

 changed to liquids by the application of heat. Metals 

 are the best examples of this phenomenon. Water exists 

 in all three states, solid, liquid, and gaseous ; as ice, water, 

 and steam. 



A solid has a definite volume and a definite shape, as a 

 stone or a piece of wood. A liquid has definite volume, 

 but the shape is that of the containing vessel. A gas has 

 neither definite volume nor definite shape, but expands 

 indefinitely as the pressure on it decreases. 



Constitution of Matter. To know that a certain sub- 

 stance is called wood, and that one article is made of glass 

 while another is made of iron, is not enough to satisfy the 

 inquiring mind. We want to know what these substances 

 are composed of. 



26 



