MATTER AND ITS PROPERTIES 53 



People are standing, and while the car moves in a straight 

 line with nearly uniform or gradually changing velocity, all 

 is well. But if the car suddenly stops, people are thrown 

 forward. Their feet stop when the car does, because the 

 weight of the body presses the feet firmly to the floor. From 



FIG. 18. MEASURES OF CAPACITY 



k 



Measures of liquids and small solids are usually in the form of a cylinder. 

 A cylinder which holds as much liquid as a cu. dm. box is called a liter (1.). 

 It holds about 1 qt. 1. To how many cu. cm. is 1 1. equivalent? 

 2. 250 cu. cm. is what part of 1 1? 



inertia, the upper part of the body continues in motion for- 

 ward, as the result shows. 



The effect of the sudden starting of a car in which people 

 are standing shows the inertia of bodies at rest; that is, 

 their tendency to remain at rest. 



52. Special Properties. Extension, weight, and inertia 

 are the only properties which belong to all matter. Different 

 kinds of matter have different special properties. Some of 

 the special properties are: 



Hardness, ability to resist being scratched. A diamond 

 cannot be scratched by steel. 



