Many students do not clearly distinguish between irradiation and contamination of an object

Quantum and Nuclear


They may also believe that radiation is radioactive and that when absorbed, the radiation can cause objects to become radioactive or that radiation can be re-emitted from objects which have previously absorbed it. For example, this may present itself as "irradiation of food results in radioactive food".

Resources to Address This

  • Use this set of diagnostic question and answers to assess students understanding of ionisation by irradiation. The questions can be useful in discussing how radiation can affect objects, leading to damage through ionisation but not contamination.

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  • Questions 8 and 9 in this set of diagnostic questions are useful in assessing students understanding of the difference between contamination and irradiation.  

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  • The context of killing bacteria on food can be used to identify whether irradiation is dangerous and has any lasting effect once the source of irradiation is removed.

    Discuss the safety of the food after the irradiation process, leading to the idea that ‘radiation’ does not stay in the food as it has not been contaminated while the irradiation process can damage cells and kill bacteria.

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  • A useful discussion about the difference between contamination and irradiation through a dialogue and through examples.

    It can be used to explain the difference between the two terms and discuss the nature of ‘radioactive material’, identifying that contamination will involve some radiative material being present.

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  • This resource aims to discuss the underlying meaning of the language used when discussing ‘radiation’, clarifying the different meanings of some of the key terms.

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  • Prather, E. and Harrington, R. () Student understanding of ionizing radiation and radioactivity, Journal of College Science Teaching.

  • Millar, R. () School students’ understanding of key ideas about radioactivity and ionizing radiation, Public Understanding of Science, 3, UK,


    DOI: 10.1088/0963-6625/3/1/004

  • Eijkelhof, H. M. C. () Radiation and risk in physics education.

  • Boyes, E. & Stanisstreet, M., () Children's Ideas about Radioactivity and Radiation: sources, mode of travel, uses and dangers, Research in Science & Technological Education, 12 (2) 145-160.

    DOI: 10.1080/0263514940120204

  • Millar, R. and Gill, J. S., () School students' understanding of processes involving radioactive substances and ionizing radiation, Physics Education, 31 (27)

    DOI: 10.1088/0031-9120/31/1/019.

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