What is an insoluble substance?

An insoluble substance is a material that does not dissolve or dissolves only in a very small amount in a particular solvent. In general science, the term is commonly used for substances that do not dissolve in water.

Examples of insoluble substances include sand, oil, wood, chalk powder, and some minerals when mixed with water. When an insoluble substance is added to a liquid, its particles do not spread uniformly throughout the liquid and may settle at the bottom or form a separate layer.

The solubility of a substance depends on factors such as the nature of the substance, the solvent, and temperature. Learning about soluble and insoluble substances helps students understand mixtures, separation methods, solutions, and many everyday processes such as filtering impurities from water.