22 FIRST YEAR COURSE IN GENERAL SCIENCE 



case, steam is formed, and it is liable to push out and scatter 

 the mixture. Even weak acid is injurious to the skin and 

 clothing. 



Record what happens in each of the following cases. If 

 no visible action occurs at once, continue to watch closely 

 for half a minute. Note differences in degree as well as in 

 kind of changes. 



Place in the add solution Observation 



1. A strip of copper alone. 



2. A strip of zinc alone. 



3. Copper and zinc together with- 



out contact outside or in the 

 acid. 



4. Copper and zinc together con- 



nected by a wire outside. 



5. Remove the metals from the 



liquid; wind the wire twice 

 around a compass from N to 

 S. Note any effect on the 

 needle. 



6. With the compass in the coiled 



wire, replace the metal strips 

 in the liquid and observe the 

 position of the needle. 



RESULTS 



1. Upon which of the two metals used does the weak acid 

 act more readily? 



2. What effect upon the position of a magnetic needle is 

 produced by an electric current passing around the needle? 



3. How do you know that it was the current and not the 

 wire that produced the effect? 



4. Name, in order, all the substances which made the 

 circuit for the current in Case 6. 



6. Name a case in which the circuit was broken. 



