58 JUNIOR GRADE SCIENCE 



QUESTIONS ON CHAPTERS IX., X., AND XI. 



31. How would you. test the accuracy of the readings of a burette ? 



32. Enumerate the different methods by which you have found the 

 specific gravity of a liquid, and mention any difficulties which you have 

 had with any two of them. 



33. Describe fully how to determine the density of milk without using 

 any form of hydrometer. 



34. Enumerate any special properties which distinguish water from mer- 

 cury, and illustrate your statements from results of your own experiments 

 or observation. 



35. A bottle when filled with water weighs 211 gm. Fifty gm. of a 

 solid are then added to the bottle, and the water which flows over is removed, 

 leaving the bottle still filled. The bottle then weighs 255 gm. Find the 

 specific gravity of the solid. 



36. How would you verify by experiment that when a body floats in 

 water the upward pressure on the body is equal to the weight of the dis- 

 placed water ? 



37. How would you prove that the weight of methylated spirit displaced 

 by a floating body is equal to the weight of the body ? 



38. On what does the apparent change in the weight of a body when 

 immersed in a liquid depend How would you verify your answer by 

 experiment ? 



A piece of wood weighs 215 gm., and when fastened to a piece of metal 

 and both immersed in water the joint weight is 166 gm. The metal alone 

 weighs 280 gm. when immersed in water. Calculate the specific gravity 

 of the wood, explaining your method. 



30. Describe fully an accurate method of determining the volume of a 

 small piece ot metal of irregular shape. 



40. Describe carefully how you would determine accurately the volume 

 of a small piece of cork. 



41. How woUld you find the volume of a piece of cork of irregular shape ? 

 What sources of error might affect the measurement ? 



42. The specific gravity of cork is 0'25, of iron 7*5. Find what weight of 

 iron can be supported in water by 1 Ib. of cork, (1) when the iron is on top 

 of the cork and entirely out of the water ; (2) when the iron is fastened 

 below the ^ork. 



43. A gold coin i,s counterpoised on a balance by means of brass weights. 

 The whole balance is then lowered into water. How will the equilibrium 

 be effected ? Explain your answer. 



44. A vessel containing water is placed on the scale pan of a balance, 

 and equilibrium produced by weights on the other pan. A solid suspended 

 from a string is lowered into the water, but not allowed to touch the vessel, 

 and it is found that 5-3 grams added to the other pan restore equilibrium. 



