Mixtures can be separated into their components by understanding and using the differences in the physical properties of the components. What are "physical properties"?
Physical properties are the properties of matter that deal with the measurable or describable state. Examples are weight, color, shape, density, area and many more. Applying the physical properties on separation of compounds is very much needed since we are relying on that property as a proof that a mixture has been separated into its components. For example, a mixture of sand and water: You know that pure water is clear and sand can be grey or dark. Since you know their physical properties, your end products should rely on that. Once you tried separating them and see that the water is not clear, you will know that the mixture has not effectively separated.
Physical properties can be observed or measured without changing the composition of matter. Physical properties are used to observe and describe matter.
Physical properties include: appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity, and many others.
The three states of matter are: solid, liquid, and gas. The melting point and boiling point are related to changes of the state of matter. All matter may exist in any of three physical states of matter.