Fine particles are separated from the bigger particles by using a sieve. Since flour is in powdered form and husk are solid particles, so sieving is used to separate them.

In threshing, the mixture is beaten in order to separate, but this principle cannot be applied here. Dried leaves are very light in weight and can be easily flown out by air. So, they can be easily separated from the sand by winnowing.

In a fixed amount of water, different amounts are dissolved for different substances. This is so because different substances are made from different atoms, ions or molecules, which interact with water in different ways.
For example, amount of salt dissolved is different from the amount of sugar dissolved in the same amount of water.

Tea leaves are unwanted substances in the tea. So they are filtered out. But after separating them, even the filtered leaves are used as manure.

In both the processes - filtration and sieving, the principle employed to separate the components is 'difference in the size'. The smaller particles or liquid passes through the sieve or filter paper. Whereas, larger particles or insoluble solid is collected on the sieve or the filter paper.