Which method can be used to separate a mixture of sand and water?

The method of filtration is appropriate for separating a mixture of sand and water because it takes advantage of the different physical states of the components. In this mixture, sand is a solid and water is a liquid. When the mixture is poured through a filter paper placed in a funnel, the solid sand particles are unable to pass through the small pores of the filter paper. As a result, the sand remains on the paper, while the water passes through as a filtrate. This method is effective because it relies on the size difference between the solid and the liquid, making it a straightforward physical separation technique.

Evaporation is not suitable here, as it would remove the water by turning it into vapor, leaving the sand behind, but it is not the most immediate or effective method for simply separating these two substances. Chromatography is used for separating mixtures of different substances, especially in solutions based on differences in their movement through a medium, which is not applicable here. Crystallisation is a technique typically used to purify solids from solutions and is not appropriate for separating a solid from a liquid in a straightforward manner. Thus, filtration is the most efficient method for this scenario.