i6 



EXPERIMENT 6. VENTILATION 



(a) Put a short piece of candle on the table. Light 

 the candle and allow it to burn until the flame becomes 

 steady, then put a beaker 

 over the candle. Is the flame 

 extinguished at once ? Why ? 



(b) Rem ove the beaker and 

 relight the candle. When the 

 flame is steady place over it 

 a lamp chimney (Fig. 10), 

 instead of the beaker. Al- 

 though the top of the chim- 

 ney is open, the flame is soon 

 extinguished. Why ? 



(c) Remove the chimney 

 and again light the candle. 

 When the flame is steady 

 replace the chimney but, in- 

 stead of allowing it to rest on the table, 

 support it on a couple of wooden blocks 

 about one inch high. Is the candle ex- 

 tinguished or does it continue to burn ? Why ? Fig- 

 ure II. 



EXPERIMENT 7. LAW OF MIXTURES 



When two bodies of unequal temperatures are near to 

 each other or are touching each other, the warm body 

 gradually loses heat and the cold body gradually gains heat 

 until both have the same temperature. If 100 gm. of water 

 at 40 is mixed with 100 gm. at 80, we obtain 200 gm. of 

 water at 60 C. The warm water has lost 20 C. and the 



FIG. 10. The 

 candle does not 

 burn well. 



FIG. ii. The 

 candle burns 

 brightly when 

 the chimney is 

 supported on 

 blocks. 



