62 LABORATORY MANUAL 



CHAPTER X 

 WATER AND AIR 



Exercise 36. A Simple Electric Cell.* 

 Object: To show how a current of electricity is 

 produced. 



Apparatus 



Strip of amalgamated zinc, 4x1 



(Strip of copper 4x1) 



Two pieces of copper wire, each 12 in. long 

 A block of wood about 4x1x1 

 Dilute sulphuric acid, about 5 C / C . 

 A compass or magnetic needle 



Note : On one side, at the mid-point of the long axis 



of the block of wood, tack 

 the strip of zinc perpen- 

 dicularly with one inch of 

 the zinc projecting above 

 the wood and two inches 

 extending below. On the 

 opposite side of the wood, 

 similarly fasten the strip 

 of copper. To the upper- 

 ends of the metallic strips 

 attach the copper wires. 



Directions : Fill the 

 Flg 21 glass about f full of the 



*This exercise is given here for those teachers who wish to 

 present to their classes some preliminary facts about electricity 

 before performing Exercise 37. 



