Understanding the concept of density

Sink

Float

Mass

Density

Volume

X

kgm3

SI unit = kg/m3

What is the density of mercury if

5 cm3 of mercury has a mass of 68g ?

= 13.6 g/cm3

A solid has a density of 2.5 g/cm3. If it occupies a volume of 20 cm3, what is its mass?

= 50 g

If a substance has a density that is higher than a liquid’s density, then it will sink

If a substance has a density that is lower than the liquid’s density, then it will float

The stone and glass stopper sink in water because it has a higher density than water

The ice cube and cork floats in water because it is less dense than water

ConclusionCork & ice cube have the lowest densityStone & glass stopper have highest density

Float = less dense

Sink = more denser

Table 4 shows four substances with their densities.

Substances Density (g/cm3)

W 0.25

X 0.95

Y 0.55

Z 1.50

Which of the following substances will float in petrol of density 0.75 g/cm3 ?

A.W and XB.W and YC.X and YD.X and Z