22 GETTING ACQUAINTED WITH THINGS 



3. Which of the following actions are chemical changes and 

 which are physical changes? Why? 



a. Melting of lead d. Boiling of water 



6. Burning of wood e. Rusting of iron 



c. Making a pencil mark on paper /. Souring of milk 



4. How can you train yourself in observation? 



REPORTS ON OUTSIDE THINGS I HAVE READ, 

 DONE, OR SEEN 



1. Report upon an article related to some topic discussed in 

 this unit. The article may be from a current number of a science 

 magazine or from some popular science book you have read. 



2. My home environment (in one of the following localities : 

 a farm, a city, a mining town). 



3. Compare the environments of the American Indian and the 

 early cliff dwellers. 



4. What superstitions do your friends have that actually 

 influence their behavior in any degree? 



5. How some important elements are obtained from compounds. 



SCIENCE RECREATION 



1. Chemical and Physical Changes. Making a smoked sun 

 glass with which one may safely look at the sun to view sun spots 

 (through a telescope) or at an eclipse. 



When a candle is lighted, notice the melting of the wax some 

 wax runs down the sides and hardens. Bring the glass down over 

 the flame. Keep it moving so that the glass will not break. Try 

 to get an even deposit of black carbon over the surface of the glass. 

 The molecules of the wax of the candle contain hydrogen and 

 carbon. When the flame is cooled, the hydrogen burns, but all the 

 carbon does not burn. This unburned carbon is deposited over 

 the surface of the glass. List the kinds of changes melting 

 wax, solidifying wax, burning wax, separation of carbon, deposit 

 of carbon on the glass. 



2. Are You Superstitious? Make a list of superstitions that 

 have to do with the number 13, broken mirrors, salt, black cats, 

 ladders, posts, moon, umbrellas, warts, etc. Tell how you could 

 subject some one of these superstitions to a scientific test to see 

 if they have any foundation of truth. 



3. How Is Your Second Sight? Place 10 pairs of objects on 

 a table. They may be of the following nature : a pair of scissors 



