Final Answer:
To separate gravel from powder, you could use a sieve or a mesh screen.
Step-by-step explanation:
A sieve is a tool designed for separating particles based on size. In the context of separating gravel from powder, a sieve with appropriately sized openings can be employed. The sieve, typically a mesh screen or perforated surface, allows smaller particles like powder to pass through while retaining larger particles such as gravel. This process is based on the principle of particle size segregation.
By shaking or agitating the mixture on the sieve, the separation occurs, and the gravel and powder are sorted into distinct fractions. This method is widely used in various industries, including construction, agriculture, and material processing, where the need for particle size classification is essential.