Sampling probes, which are like giant syringes, take samples from waste tanks at the Hanford site in Washington.

(Source: DOE photo)

 A part or quantity selected from a larger group of items or quantity of material for inspection or analysis. The term has two meanings:

• In statistical sampling, a sample is a subset of items selected by some deliberate process from a defined group (population) of items and evaluated to gain information about the whole group (population).
• In material sampling for analysis, a sample is a small quantity of material taken from one item or container for measurement. A composite sample is obtained by taking several quantities from one or more containers, mixing them together and then selecting one or more aliquots for measurement.