How is the mixture of wheat flour and sand separated?

1. Sieving:

* Principle: Flour particles are much smaller than sand grains.

* Method: Use a fine-mesh sieve. Pour the mixture through the sieve. The flour will pass through, leaving the sand behind.

2. Using a Strong Wind or Air:

* Principle: Flour is lighter than sand.

* Method: Spread the mixture on a flat surface. Blow a strong gust of air or use a hair dryer on a high setting. The wind will carry away the lighter flour particles, leaving the sand behind.

3. Water and Sedimentation:

* Principle: Flour dissolves in water, while sand does not.

* Method:

1. Add water to the mixture and stir well.

2. Allow the mixture to settle.

3. Carefully pour off the water, which will contain the dissolved flour.

4. The sand will settle at the bottom.

4. Using a Magnet:

* Principle: Sand does not contain iron, but some types of flour might have small iron particles (for example, from grinding equipment).

* Method: Use a strong magnet to remove any iron particles that might be present in the flour. This method might not be very effective for separating all of the flour and sand.

Important Note: No method will achieve a 100% perfect separation. Some very fine sand particles might pass through the sieve, and some flour might remain attached to the sand grains.