Page 88 - Physics

Physics for Secondary Schools

Acti vity 4.3 Initial volume of water,V = 60 cm 3
Aim: To determine the density of 1
an irregular shaped object. Final volume of water, V = 70 cm 3
2
Materials: Eureka can, beaker, Volume of water displaced, V = V − V
measuring cylinder, string, 2 1
triple beam balance, or volume of the solid = volume of water
digital beam balance and displaced
3
stones of different shapes Volume of a solid = 70 cm − 60 cm 3

3

Procedure Volume of a solid = 10 cm .
1. Measure the mass of irregular stones But, ρ = m
using a beam balance and record s V
your results in Table 4.3. 50 g
2. Measure the volume of each stone ρ = 10 cm 3
s
and record in Table 4.3.
Table 4.3 = 5 g/cm 3

Stone Mass, Volume, Density, Therefore, the density of the irregular
3
identity m V ρ solid X is 5 g/cm .

Task 4.2

If you want to determine the density of
3. determine the density of each stone. stone:
4. compare the densities of different
stones. (a) Suggest the suitable instruments/
apparatus you may need to carry out
Question this task.
What can you conclude from your (b) If some of the apparatus are not there
observation? in your home environment, what
alternative you may use to carry out
the activity?
Example 4.4

An irregular solid X has a mass of Density of insoluble granules
50 g. When it is totally immersed in Determination of the density of small
the water of volume 60 cm , the fi nal insoluble particles such as sand grains
3
water volume is 70 cm . Calculate the is also possible. Unlike other solids,
3
density of the irregular solid X.
granules must be held in some type of
Solution container while being measured. This
Mass of irregular solid, m = 50 g could be realised by using a density bottle.

82
Student’s Book Form One

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