A certain factory has waste products of large wood chips, large rocks, and sand. These materials are all mixed together. Large amounts of this mixture are produced every day. The materials need to be separated from each other so that they can be reused for other purposes. Four suggested methods for separating the mixture are shown below. Each method uses a tank full of water.

Method 1
Place the mixture in water.
Remove everything that floats on top of the water.
Allow the water to evaporate.
Method 2
Remove the rocks from the mixture by hand.
Place the remaining mixture in water.
Remove everything that floats on top of the water.
Method 3
Place the mixture in water.
Remove anything that is not dissolved in the water.
Allow the water to evaporate.
Method 4
Pass the mixture through a screen.
Place what does not pass through the screen in water.
Remove everything that floats on top of the water.

Which method would be most effective for separating the mixture?