COMBUSTION 5 



4. COMBUSTION 



We have seen that in explosions the burning took place 

 rapidly, and throughout the whole mass at the same time. 

 Explosions are, however, only one kind of chemical action 

 which is called combustion. We are all familiar with the 

 combustion which occurs in fireplaces, stoves, and lamps. 

 This is called ordinary combustion, because we are familiar 

 with it, but the most common sort of combustion is not 

 generally recognized. 



Before considering the kinds of combustion it might be 

 well to understand what this phenomenon really is. 



Experiment i . Ordinary Combustion. 



Apparatus : Argand lamp chimney, cork stopper to fit bot- 

 tom of chimney and one to fit top of chimney, ' wire nail 

 about one inch long, small pan or saucer. 



Materials : Piece of candle about two inches long, matches. 



a. Cut notches on side of larger cork so that the amount 

 removed is about one third of the cork, push nail through 

 the center of the cork and stick the candle on it. Then light 

 candle and let it burn in the open air. 



Note waviness of the flame and the tendency to smoke. 

 Why is the flame wavy? 



6. While the candle is burning, lower the Argand chimney 

 over it, and push the chimney down over half the length of the 

 cork. 



Is the flame different now ? Describe the difference. What 

 makes the difference ? 



c. Push the chimney down over the whole of the cork, so 

 that the bottom of the chimney rests on the table, and then 

 put the other cork into the top of the chimney. 



