4 LABORATORY EXERCISES 



EXERCISE 3 

 THE MEASURING OF VOLUME AND CAPACITY 



Apparatus. Two cubical blocks, metric rule, a marble about 1 in. 

 in diameter, graduated cylinder, half-pint measuring cup with vertical 

 sides. 



a. The Volume of a Marble. Place two cubical blocks 

 tightly against the edge of a metric rule (Fig. 4), and between 

 the blocks place a spherical marble. By measuring the dis- 

 tance between the two blocks get the diameter of the marble 

 in centimeters and tenths. Mathematics teaches us that the 

 volume of a sphere is very nearly ^X^X the cube of the 



Fio. 4. 



diameter. Suppose that the marble is 2 cm. in diameter; the 

 volume of the marble would be -JX^XS, or 4.19+ cu. cm. 

 In the same way calculate the volume of the marble given 

 you, and record it, together with all your work. 



Volume by Displacement. We can also get the volume of 

 the marble by finding out how much water the marble can push 

 out of the way, or displace, (Fig. 5 of text) . Half fill a graduated 

 cylinder with water, and read the water level accurately. To 

 do this, have your eye on a level with the water, and read the 

 mark at the under edge of the curved surface (meniscus). Put 

 down the reading. Now put the marble into the water, and 

 read the new level. Subtract the first from the second reading. 

 What is the volume of the marble by this method? Compare 

 the two results. 



Record your results systematically, as in Exercise 2. 



