178 EXPERIMENTAL GENERAL SCIENCE 



18. Why can one whirl a bucket of water in a perpendicular circle 

 without spilling it? 



19. In large laundries, the clothes are often dried by being placed in 

 a cylinder having many openings and revolved rapidly. How does this 

 dry the clothes? 



20. The cream separator used in dairies is essentially a rapidly revolv- 

 ing bowl into which the milk is run. Do you infer that the cream goes 

 to the center or to the outer part of the bowl. Why? 



21. Where does a stream run faster, near the banks or in midstream? 

 Why? 



22. Would an increase in the friction between the wheels of a loco- 

 motive and the rails be advantageous or not? Why? 



23. Explain the use of sand on the rails when the track is slippery. 



24. A sheet of paper flutters to the ground but the same paper made 

 into a ball falls more rapidly. Why? 



25. Why will a coin fall to the ground more quickly than a feather? 



26. Why do ball bearings make machines run more easily? 



27. Why are the shafts of fine watches set in bearings made of precious 

 stones? 



28. On which would a marble roll farther, a bare floor or one covered 

 with carpet? Why? 



29. Why is it more difficult to walk against a stiff breeze than against 

 a light one? 



