CONVECTION 25 



6. 3802:286. Convection. 



c. 1804:296-298. Convection. 



d. 1805:325-326. Convection. 



e. 1806:305-306. Convection. 

 /. 1807:166-167. Convection. 



g. 1808 : 217. Convection in Gases. 



h. 1809 : 160. Convection. 



Experiment 9. Convection in Gases. 

 Apparatus: Chalk box and cover, piece of window glass 

 to fit as a sliding cover in chalk box. 



Materials: Candle not over 2" long, matches, touch paper.* 



a. Cut a hole one inch square in one side of the box close 

 to one end and another hole in the same side of the box, but 

 close to the other end. Opposite this latter hole'cut a third, in 

 the other side of the box. Place the box on the table with the 

 end having two holes near it at the top. Light a candle and 

 place it near the bottom hole. Take the wooden cover of the 

 box and make a partition of it, dividing the box lengthwise 

 into two equal parts. In this partition, cut a hole near the 

 bottom. Slide the glass cover in place and apply smoking 

 touch paper near the lower hole. Where does the smoke go ? 

 Why? 



b. Close lower hole and place touch-paper near upper hole 

 of other side. Describe and explain. 



Experiment 10. Convection in Water. 

 Apparatus : Test tube, test-tube holder, lamp. 

 Materials: Sawdust. 



a. Fill a test tube nearly full of water and mix in it a very 

 small pinch of fine sawdust. Hold the test tube vertically 



* To make touch-paper : Soak blotting paper in a water solution of po- 

 tassium nitrate (saltpeter) containing all of the potassium nitrate which will 

 dissolve. Dry and cut into strips j inch wide. 



