Why is the sample size important?

Test tubes are useful for handling small volumes of solution. In a beaker, a small volume is spread out over a large area, and mixing is ineffective.

Video: Mixing a small quantity in a small vs. large container ( 4.84 M )

Conversely, large volumes are inappropriate for test tubes, because liquid at the top of the test tube may never come in contact with the liquid at the bottom, resulting in incomplete mixing.

Video: Attempt to mix larger volume in test tube ( 2.25 M )