Screening (or sieving) is a method typically used to separate solid particles based on size. Therefore, it will be used to separate a mixture in the situation where if the components have different colors.
While screening is not primarily based on color, if you are visually separating solids of different colors (like grains or sand of different colors), it can be performed as a screening process. However, if you strictly define screening, the best fit would generally be based on size differences rather than color.
For clarity:
- If the mixture is a solid suspended in a gas: This situation often requires filtration rather than screening.
- If the components have different boiling points: This would typically involve distillation.
- If the mixture is a solid dissolved in a liquid: This would require filtration or evaporation.
- If the components have different colors: This could involve screening if they can be physically separated by visual identification.
Overall, screening is best for separating solids based on size rather than color.