In general, a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing(s). The things could be countable objects such as individual items available as units for sale, or an uncountable material. Even though the word "sample" implies a smaller quantity taken from a larger amount, sometimes full biological or mineralogical specimens are called samples if they are taken for analysis, testing, or investigation like other samples. They are also considered samples in the sense that even whole specimens are "samples" of the full population of many individual organisms. An act of obtaining a sample is called "sampling," which can be performed manually by a person or via an automated method. Samples of material can be taken or provided for testing, analysis, investigation, quality control, demonstration, or trial use. Sometimes, sampling may be continuously ongoing.
In the field of science, a representative liquid sample taken from a larger amount of liquid is sometimes called an "aliquot."
The material may be solid, liquid, gas; a material of some intermediate characteristics such as gel or sputum, tissue, and organisms; or a combination of these. Even if a material sample is not countable as individual items, the quantity of the sample may still be describable in terms of its volume, mass, size, or other such dimensions. A solid sample can come in one or a few discrete pieces, or it can be fragmented, granular, or powdered. A section of a rod, wire, cord, sheeting, or tubing may be considered a sample. Samples which are not a solid piece are commonly kept in a container of some sort.
- O'Toole, M.T., ed. (2011). Mosby's Medical Dictionary (9th ed.). Elsevier Mosby. p. 1592. ISBN 9780323085410.
- Elliott, J.E. (1984). "Collecting and Archiving Wildlife Specimens in Canada". In Lewis, R.A.; Stein, N.; Lewis, C.W. (eds.). Environmental Specimen Banking and Monitoring as Related to Banking. Martinus Nijhoff Publishers. pp. 45–66. ISBN 0898386217.
- Department of Defense; Environmental Protection Agency; Nuclear Regulatory Commission (2000). "Chapter 7: Sampling and Preparation for Laboratory Measurements". Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) (PDF). Nuclear Regulatory Commission. p. 7-1. Retrieved 5 July 2018.
Sampling is the process of collecting a portion of an environmental medium as representative of the locally remaining medium.
- Gruiz, K.; Meggyes, T.; Fenyvesi, É., eds. (2016). Engineering Tools for Environmental Risk Management - 3: Site Assessment and Monitoring Tools. CRC Press. p. 43. ISBN 9781315778761.
- Hazelton, C. (1998). "Variations between Continuous and Spot‐Sampling Techniques in Monitoring a Change in River‐Water Quality". Water and Environment Journal. 12 (2): 124–9. doi:10.1111/j.1747-6593.1998.tb00161.x.
- McNaught, A.D.; Wilkinson, A., eds. (2008). "aliquot". Compendium of Chemical Terminology (2nd ed.). Blackwell Scientific Publications. p. A00218. doi:10.1351/goldbook.A00218. ISBN 0967855098. Retrieved 5 July 2018.
- Cullum, B.M.; Vo-Dinh, T. (2014). "Chapter 1: Preparation of Liquid and Solid Samples". In Gauglitz, G.; Moore, D.S. (eds.). Handbook of Spectroscopy (2nd, Enlarged ed.). Wiley. pp. 3–14. doi:10.1002/9783527654703.ch1. ISBN 9783527654703.