What is the most rapid and accurate way to reduce the size of a sample?

The most rapid and accurate way to reduce the size of a sample is through splitting. This method involves dividing a larger sample into smaller, equal portions without changing the sample's composition. Splitting ensures that each smaller portion remains representative of the whole, making it an effective way to manage sample size for testing or analysis.

In contrast, grinding involves physically reducing the particle size of the material, which can introduce variability or alter the original characteristics of the sample. Sifting, on the other hand, serves to separate particles based on size rather than evenly reducing the sample size. Mixing combines different components together and does not effectively reduce sample size or maintain its representativeness. Therefore, splitting stands out as the most efficient and accurate approach to reduce the size of a sample while preserving its integrity for further analysis.