96 



Our Surroundings 



Fill the wide-mouthed bottle three-fourths full of the solution 

 of bicarbonate of soda. Nearly fill the test tube with sulphuric 

 acid and place it in the wide-mouthed bottle, in such a way that 

 the liquids will not mix when the bottle is upright. Insert the 

 glass tube in the stopper. Attach the rubber 

 tube to the upper end of the glass tube. Place 

 the stopper in the wide-mouthed bottle. Then 

 tip the bottle so as to empty the contents of the 

 test tube into the bicarbonate solution. Notice 

 that a gas is formed. It is carbon dioxide, 

 which forces the soda solution through the tube. 

 Play this solution upon a small fire made in 

 the tin can, and note the result. 



Fire extinguishers should be placed at 

 danger points in home or school. They should 

 be inspected and refilled every year. 



Fire and Fire Fighting. The fire losses 

 in the United States total more than one-half 

 billion dollars per year. A large percentage 

 of these fires is caused by carelessness. The 

 smoker throws away a lighted match, the 

 painter leaves an oily rag where there is poor 

 circulation of air around it, or an electrician 

 does a poor job of wiring. Most fires could 

 be prevented with proper precaution. 



There are two general methods of fighting 

 a fire. One method is to blanket it, thereby 

 shutting out the air and thus smothering the 

 fire. The old-time method of throwing dirt 

 over burning material is an example of the 

 blanketing method. The other method is to 

 cool the burning material below the tempera- 

 ture at which it takes fire. The most common 

 extinguisher used in the cooling process is 

 water. When the water strikes the burning material it instantly 

 turns to steam and in so doing uses up much of the heat that 

 is necessary to keep the fire going. Extinguishers containing 



A SIMPLE FIRE 

 EXTINGUISHER 



