i PHYSICAL PROPERTIES AND STATES OF MATTER 19 



of a vessel, it at once flows. This power of flowing is not perfect in 

 liquids, or we may say, liquids are not perfectly mobile. They all 

 possess a certain degree of viscosity. 



Other Properties of Liquids. They find their level. They com- 

 municate pressure equally in all directions. They can be separated 

 into drops which will run together again. 



Distinctive Characters of Gases. They possess fluidity to a much 

 more marked degree than liquids. Unlike liquids they can easily 

 be compressed into a much smaller space. A gas, however small its 

 volume, will spread out and do its best to fill a vessel, however 

 large. Expressed shortly we say, gases are easily compressible and 

 expand indefinitely. 



Constancy of Weight in different States. When a solid is converted 

 into a liquid, or a liquid into a vapour, no change of weight is 

 experienced. 



Matter is Indestructible. There is a certain fixed amount of 

 matter in the universe which never gets any less and never any 

 greater. Whatever changes may occur in the composition of matter 

 there is never any loss of weight. 



QUESTIONS ON CHAPTER I. . 



1. What do you understand by "matter," or, a "material 

 thing" ? 



2. Give some of the properties which are possessed by all kinds of 

 matter and explain in your own words what is meant by a 

 property. 



3. Describe experiments which prove : 



(a) That solids are porous. 



(b) That liquids, too, contain pores. 



4. What experiment could you perform to show that a solid, say 

 a billiard ball, is elastic ? Explain as well as you can what you 

 mean by elasticity. 



5. The same portion of matter can, under suitable conditions, 

 assume different states. Describe fully some experiment which 

 illustrates this statement. 



6. What evidence can you give that the different states of matter 

 gradually shade into one another ? 



7. What properties are generally associated with matter in the 

 solid form ? Give a definition of a solid which includes the chief of 

 these. 



8. In what respects are liquids different from solids ? 



9. How do gases and liquids differ ? 



10. What property in particular is possessed by liquids and not 

 by solids ? And what character has a gas which neither liquids nor 

 solids possess ? 



11. What property is it which liquids possess which enables them 

 to form drops ? Describe another experiment which also shows the 

 possession of this property by liquids. 



12. Give in the form of a definition the distinctive properties of a 



c 2 



