452 GENERAL SCIENCE 



48. Why do automobiles tear up the surface of a road? 



49. Why do cream separators remove the cream from the milk? 

 0. Why does cloth shrink when it is wet? 



51. Why is it not possible to write on blotting paper? 



52. What is done to paper which is to be used as writing paper? 



53. Why will camphor dissolve in alcohol and not in water? 



54. Why will clothes lines tighten up during a rain storm? 



55. Why is it possible to mark on the blackboard with chalk? 



56. Why cannot one write as well on glass? 



57. Why is there a slit in a pen point? 



58. Why does a rough towel dry the body more quickly than 

 a smooth one? 



59. Why is it possible to paint wood and iron? 



60. Why is it possible to make a mark on paper with a lead 

 pencil? 



61. Why is it not possible to write on paper with a slate pencil? 



62. Why does salt become damp? 



63. Why must pails and tubs made from wood be kept damp? 



64. Why do some people place flour on a fresh ink stain on the 

 tablecloth? 



65. Why is it almost impossible to remove kerosene or ink stains 

 from marble? 



66. Why are lips put on pitchers? 



67. Why is it almost impossible to wash greasy hands with water 

 alone? 



68. Why is it difficult to untie a wet knot? 



69. Why does oil float on water and alcohol mix with water, 

 both liquids being lighter than water? 



70. Why does molasses stick to things? 



71. Why does glue make things stick together? 



72. Why does heating iron make it possible to weld it? 



GENERAL QUESTIONS FOR INVESTIGATION AND DISCUSSION 



1. Why does one lean forward when climbing a steep hill and 

 backward when descending? 



2. When carrying a heavy package in one hand why does one 

 lean toward the opposite si'de? 



