People are exposed to sources of radiation in all aspects of everyday life. Radioactive sources can be very useful but need handling carefully to ensure safety.
Shining visible radiationEnergy carried by particles from a radioactive substance, or spreading out from a source. from a torch beam onto a hand, lights the hand up because the hand has been exposed to light.
Exposing objects to beams of radiation is called irradiationProcess of exposing an object to a source of radiation. Eg fruit exposed to gamma rays in order to destroy bacteria is said to have been irradiated.. The term applies to all types of radiation including radiation from the nucleiNuclei is the plural of nucleus. The nucleus is the central part of an atom. It contains protons and neutrons, and has most of the mass of the atom. of atomAll elements are made of atoms. An atom consists of a nucleus containing protons and neutrons, surrounded by electrons..
Irradiation from radioactive decayThe process in which unstable atomic nuclei break apart or change, releasing radiation as they do so. can damage living cells. This can be put to good use as well as being a hazard.
Irradiation for sterilisation
Irradiation can be used to preserve fruit sold in supermarkets by exposing the fruit to a radioactiveWhen unstable atoms give off particles that can be harmful to humans. source - typically cobalt-60. The gamma rayThe shortest wavelength and highest energy part of the EM spectrum. Produced by radioactive materials. emitted by the cobalt will destroy any bacteria on the fruit but will not change the fruit in any significant way. The process of irradiation does not cause the irradiated object to become radioactive.
Advantages and disadvantages of irradiation
Advantages
sterilisation can be done without high temperatures
it can be used to kill bacteria on things that would melt
Disadvantages
it may not kill all bacteria on an object
it can be very harmful - standing in the environment where objects are being treated by irradiation could expose people’s cells to damage and mutationA random and spontaneous change in the structure of a gene, chromosome or number of chromosomes.
