Physical and chemical changes
Liquid water and ice are both composed of water molecules. Melting the ice cube doesn't change the chemical composition of the molecules.
Measuring jar (cup)
To transfer a desired volume of liquid, a measuring jar is used. As the composition of water is not effected during the process, volume is a physical property
As we look at our surroundings, we observe a large variety of things with different shapes, sizes and textures. How can we distinguish or characterize those substances? Every substance has its own set of properties or characteristics that allow us to distinguish it from other substance. In chemistry we can view the substances on both the macroscopic level and the microscopic level. On macroscopic level we can directly observe the substance with our naked eye and we can feel it all over. But microscopic level is the level of small particles like atoms and molecules.
For example, at macroscopic level solids possesses definite shape and size but at microscopic level there is a regular frame work of atoms and molecules in a crystal lattice. We express the properties of matter in both of these levels. The important macroscopic properties of matter are length, area, mass, volume, weight and density. The important microscopic properties are mass, speed, kinetic energy of atoms or molecules that make up a substance.
These properties of substances are also classified into − physical properties and chemical properties. Physical properties are those properties which can be measured or observed without changing the identity or the composition of the substance. Some examples of physical properties are mass, volume, weight, density, color, odor, melting point, boiling point, density etc.
A chemical reaction should be carried out between the substances to measure or observe the chemical properties of a substance. Chemical properties are characteristic reactions of different substances which include acidity, basicity, combustibility etc.
Many physical properties of matter such as length, area, volume are quantitative in nature. A quantitative property can be measured and represented by a number, followed by units in which it is measured. For example, volume of a liquid can be represented as 5l. Here 5 is the number and ' l 'denotes litre – the unit in which the volume is measured.