Page 118 - Innovator's Science-8

Density is the mass of an object or substance divided by its volume. The
formula to find density is: Density = Mass/Volume

This means if two objects are the same size but one is heavier, the heavier
one has more density. For example, a metal block and a piece of wood can
be the same size, but the metal block feels heavier because it has a higher

density. Density helps us understand why some things float in water and
others sink — objects with less density than water float, while those with
higher density sink. Density is an important property used to identify

substances and understand their behaviour.
The density of a substance is independent of its shape or size. However, it is
dependent on temperature and pressure. Pressure primarily affects the

density of gases, while its effect on solids and liquids is negligible.
Science Density is the measure of how much mass is packed into a certain volume of
Bytes

a substance. It tells us how heavy something is for its size. The units used for
Testimony
A huge steel ship floats density depend on the units of mass and volume. In the International
on water even though System of Units (SI), mass is measured in kilograms (kg) and volume in cubic
steel is heavier than
water! This happens meters (m³). Therefore, the SI unit of density is kilogram per cubic meter
because the ship's shape (kg/m³). For liquids and smaller samples, density is often expressed in
traps a large volume of grams per milliliter (g/mL) or grams per cubic centimeter (g/cm³) for
air, making it overall
density less than that of convenience. These units help us compare how dense different materials
water. are and understand their properties in everyday life and scientific work.

Conversion Factor For Density

1 kg/m³ = 1000 g/m³ = 1000 g/1000 L = 1 g/L = 1 g/1000 mL = 1 g/1000cm³

Water is one of the most common substances on Earth and has some
special properties. At room temperature, 1 mL of water has a mass of
nearly 1 gram. This means that the amount of space, water takes up is
almost equal to its weight. For the measurement of the mass of water, we
generally consider the volume in mL and it’s mass in g. Hence, 10 mL of

water would be approximately 10 g. Similarly, 100 mL of water would be
approximately 100 g.

Suppose the mass of an aluminium block is 27 g and its volume is 10 cm³, its
density is 2.7 g/cm³.

From this, it can be said that aluminium is 2.7 times denser than water. We
express this fact by saying that the relative density of aluminium with
respect to water is 2.7. It is a number without any units.

Relative density of any substance with respect to water= Density of that
substance /Density of water at that temperature

118
Science-8