Understanding Sieving
Sieving is a physical separation technique widely used to separate particles based on size. It is particularly effective in various applications, including cooking, construction, and laboratory settings.

How Sieving Works
- A sieve consists of a mesh or perforated material that allows smaller particles to pass through while retaining larger ones.
- When a mixture is poured onto the sieve, the larger particles remain on the surface, while the smaller particles fall through the openings.

Applications of Sieving
- **Culinary Use:** In cooking, sieving is used to separate flour from lumps or to remove larger particles from sugar.
- **Construction:** In construction, sieving is essential for separating different sizes of aggregates used in concrete.
- **Laboratory:** In laboratories, sieving helps in analyzing soil or other granular materials for research purposes.

Comparison with Other Techniques
- **Filtration:** Unlike sieving, which separates based on size alone, filtration is used primarily for separating solids from liquids using a filter medium.
- **Winnowing:** This technique separates lighter materials from heavier ones using air currents, often used in agriculture for grain separation.
- **Churning:** Churning is a process used to separate cream from milk and is not related to particle size.

Conclusion
In summary, sieving is the correct answer as it specifically employs a sieve to separate particles based on their size, making it a fundamental method in various fields. Understanding this technique enhances one’s ability to analyze and manipulate materials effectively.

Sieving involves using a sieve to separate particles based on size.