MATTER AND ITS MEASUREMENT 



FIG. 1. 

 Flask with 

 a glass-stop- 

 pered tube. 



one who wants to understand and to use scientific methods and 

 apparatus in the home, in the shop or store, on the farm in short, 

 anywhere in his daily life. 



4. Matter. Suppose we examine a number of objects, 



such as pieces of marble, sulphur, wood, lead, etc. They 

 are certainly unlike in color, size, and shape. 

 Are they alike in any particulars? In the first 

 place, they all take up room, or occupy space. 

 We cannot think of a body that does not. A 

 second way in which objects are alike is that all 

 of them have weight (cf. 20). We accept these 

 statements readily when we think of lead, of 

 marble, of water, of rock. These are solids or 

 liquids, and are readily seen and handled. But 

 even invisible gases, like the air, take up room 

 and have weight, just as solid and liquid objects 



do. A vessel, such as a flask (Fig. 1), 



from which the air may be removed, is 



lighter when empty than when full of air. 



Again, a vessel full of air cannot be filled 



with water unless the air is allowed to 



escape. We see this when we try to pour 



water rapidly into a narrow-mouth bottle; 



the water can enter only a little at a time, 



as bubbles of air come out to make room 



for it. Another illustration is seen in the 



construction of a kerosene can (Fig. 2). The can has 



an opening at the top not only to allow the can to be 



filled with kerosene, but also to permit air to enter in 



a steady stream as the kerosene is poured out of the 



spout. 



Fio. 2. 



As kerosene comes out 

 air enters. 



