Water is an odourless, tasteless, transparent, and colourless chemical substance, which is the main constituent of this planet’s lakes, oceans, streams, and the fluids of most living organisms. Density is the mass per unit volume of a substance.
Some poperties of water is given in the table below:
What is the Density of Water?
As discussed, the density of a material is defined as its mass per unit volume. It’s a measurement of how tightly matter is packed together. The density of a substance can be explained as the relationship between the mass of the substance and volume it takes up.
The Density of Water can be defined as:
It is the weight of the water per its unit volume, which depends on the temperature of the water.
Factors Affecting Water Density
There are several factors which can affect the density of a substance. Some factors which affect the density of water is given in the points below.
- The density of water is around approximately about 1 gram/ cubic centimetre (1 g/cm3).
- It is temperature dependent, but this relation is said to be non- linear and also it is unimodal in nature rather than monotonic.
- When it is cooled from the room temperature, the liquid water tends to become increasingly dense, as with another kind of substances, but approximately at about 4°C, pure water is said to reach its maximum density.
- As it gets cooled further, it tends to expand and becomes less dense. This kind of unusual negative thermal expansion is related to strong, intermolecular forces, orientation-dependent, or interactions and it is observed in the form of molten silica.
Density VS Temperature
Water does not have an absolute density as its density varies with temperature. It has a higher density in the liquid state than the solid. Check the Density VS Temperature Graph given below to understand how density changes with temperature.
Density of Water at Various Temperature Scales
The water density varies for different temperature. The density (in kg/m3) of water for different temperature scale (ranging from 100 °C to -30 °C) is given in the table below.
|Temperature||Density in kg/m3|
Density of Water Experiment
To understand the density of water, let’s do a small experiment. We will need a tall glass cup, honey, water, coconut oil and food colouring,
Step 1: Pour a one-quarter cup of honey,
Step 2: Pour a one-quarter cup of coloured water gently on top of the honey.
Step 3: pour a one-quarter cup of coconut oil on top of the coloured water.
Now, you will notice that different substance has different density, which means for the same volume different substances weigh differently, as they weigh differently heavier substances tend to settle at the bottom, like honey and lighter material like oil tend to float at the top.
Density of several liquids with different specific gravities
Let’s extend our experiment further for more liquids, this time, we will use several liquids with different specific gravities, use the table given below for reference.
If you wish to learn more physics concepts with the help of interactive video lessons, download BYJU’S – The Learning App.
Frequently Asked Questions on Density Of Water
Why does ice float in water?
The maximum density of water occurs around 4° Celsius. The density of ice is less than liquid water, so it floats. Upon freezing, the ice density decreases by about 9%.
What is the density of sea water?
At the sea surface, the density of ocean water is about 1027 kg/m3.
Why does water never has an absolute density?
As its density varies with temperature, water never has an absolute density.