CHEMISTRY OF COMMON THINGS n 



when the water is boiling. When water boils steam is 

 formed. Steam consists of water molecules which are 

 moving so fast, and in every direction, that if they 

 should bump against one another they would bounce 

 apart again like two flying baseballs. If they should 

 strike a wall or any other object, the molecules would 

 rebound the same as a baseball does when thrown 

 against an object. 



The molecules composing steam are free to move in 

 every direction. Steam is a gas. The molecules of 

 gases are very active. If illuminating gas is turned on 

 in the house without lighting it, you can soon smell it 

 because the molecules spread all through the house. 

 When perfume and ammonia bottles are opened, some of 

 the molecules escape and travel through the air with 

 great speed. They can easily be detected by the smell. 



In solids the molecules move slowly and within a very 

 limited space. In liquids the molecules move with greater 

 speed than in solids, and they move around and over 

 one another with ease. In gases the molecules move with 

 very high speed, much greater than in liquids, and re- 

 bound from one another or from any object that they may 

 strike. 



10. Atoms. Molecules of most substances such as 

 water, sugar, salt, and chalk are not simple molecules 

 but complex ones. These complex molecules can be 

 divided into more simple forms. But when the water 

 molecule is broken up into its more simple forms, these 

 simpler forms do not have the properties of water as the 

 molecule does. The same is true of all other complex 

 molecules. The simpler forms do not have the same 

 properties as the molecules. These simpler forms or 

 divisions of- the complex molecules are called atoms,. 



